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Posted to commits@cassandra.apache.org by sl...@apache.org on 2013/09/05 16:38:29 UTC
svn commit: r1520330 [2/2] - in /cassandra/site/publish/doc/cql3:
CQL-1.2.html CQL-2.0.html
Modified: cassandra/site/publish/doc/cql3/CQL-2.0.html
URL: http://svn.apache.org/viewvc/cassandra/site/publish/doc/cql3/CQL-2.0.html?rev=1520330&r1=1520329&r2=1520330&view=diff
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--- cassandra/site/publish/doc/cql3/CQL-2.0.html (original)
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-<?xml version='1.0' encoding='utf-8' ?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><title>CQL</title></head><body><p><link rel="StyleSheet" href="CQL.css" type="text/css" media="screen"></p><h1 id="CassandraQueryLanguageCQLv3.1.0">Cassandra Query Language (CQL) v3.1.0</h1><span id="tableOfContents"><ol style="list-style: none;"><li><a href="CQL.html#CassandraQueryLanguageCQLv3.1.0">Cassandra Query Language (CQL) v3.1.0</a><ol style="list-style: none;"><li><a href="CQL.html#CQLSyntax">CQL Syntax</a><ol style="list-style: none;"><li><a href="CQL.html#Preamble">Preamble</a></li><li><a href="CQL.html#Conventions">Conventions</a></li><li><a href="CQL.html#identifiers">Identifiers and keywords</a></li><li><a href="CQL.html#constants">Constants</a></li><li><a href="CQL.html#Comments">Comments</a></l
i><li><a href="CQL.html#statements">Statements</a></li><li><a href="CQL.html#preparedStatement">Prepared Statement</a></li></ol></li><li><a href="CQL.html#dataDefinition">Data Definition</a><ol style="list-style: none;"><li><a href="CQL.html#createKeyspaceStmt">CREATE KEYSPACE</a></li><li><a href="CQL.html#useStmt">USE</a></li><li><a href="CQL.html#alterKeyspaceStmt">ALTER KEYSPACE</a></li><li><a href="CQL.html#dropKeyspaceStmt">DROP KEYSPACE</a></li><li><a href="CQL.html#createTableStmt">CREATE TABLE</a></li><li><a href="CQL.html#alterTableStmt">ALTER TABLE</a></li><li><a href="CQL.html#dropTableStmt">DROP TABLE</a></li><li><a href="CQL.html#truncateStmt">TRUNCATE</a></li><li><a href="CQL.html#createIndexStmt">CREATE INDEX</a></li><li><a href="CQL.html#dropIndexStmt">DROP INDEX</a></li></ol></li><li><a href="CQL.html#dataManipulation">Data Manipulation</a><ol style="list-style: none;"><li><a href="CQL.html#insertStmt">INSERT</a></li><li><a href="CQL.html#updateStmt">UPDATE</a></li>
<li><a href="CQL.html#deleteStmt">DELETE</a></li><li><a href="CQL.html#batchStmt">BATCH</a></li></ol></li><li><a href="CQL.html#queries">Queries</a><ol style="list-style: none;"><li><a href="CQL.html#selectStmt">SELECT</a></li></ol></li><li><a href="CQL.html#types">Data Types</a><ol style="list-style: none;"><li><a href="CQL.html#usingdates">Working with dates</a></li><li><a href="CQL.html#counters">Counters</a></li><li><a href="CQL.html#collections">Working with collections</a></li></ol></li><li><a href="CQL.html#functions">Functions</a><ol style="list-style: none;"><li><a href="CQL.html#tokenFun">Token</a></li><li><a href="CQL.html#timeuuidFun">Timeuuid functions</a></li><li><a href="CQL.html#blobFun">Blob conversion functions</a></li></ol></li><li><a href="CQL.html#appendixA">Appendix A: CQL Keywords</a></li><li><a href="CQL.html#changes">Changes</a><ol style="list-style: none;"><li><a href="CQL.html#a3.1.0">3.1.0</a></li><li><a href="CQL.html#a3.0.5">3.0.5</a></li><li><a href="C
QL.html#a3.0.4">3.0.4</a></li><li><a href="CQL.html#a3.0.3">3.0.3</a></li><li><a href="CQL.html#a3.0.2">3.0.2</a></li><li><a href="CQL.html#a3.0.1">3.0.1</a></li></ol></li><li><a href="CQL.html#Versioning">Versioning</a></li></ol></li></ol></span><h2 id="CQLSyntax">CQL Syntax</h2><h3 id="Preamble">Preamble</h3><p>This document describes the Cassandra Query Language (CQL) version 3. CQL v3 is not backward compatible with CQL v2 and differs from it in numerous ways. Note that this document describes the last version of the languages. However, the <a href="#changes">changes</a> section provides the diff between the different versions of CQL v3.</p><p>CQL v3 offers a model very close to SQL in the sense that data is put in <em>tables</em> containing <em>rows</em> of <em>columns</em>. For that reason, when used in this document, these terms (tables, rows and columns) have the same definition than they have in SQL. But please note that as such, they do <strong>not</strong> refer to the co
ncept of rows and columns found in the internal implementation of Cassandra and in the thrift and CQL v2 API.</p><h3 id="Conventions">Conventions</h3><p>To aid in specifying the CQL syntax, we will use the following conventions in this document:</p><ul><li>Language rules will be given in a <a href="http://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form">BNF</a> -like notation:</li></ul><pre class="syntax"><pre><start> ::= TERMINAL <non-terminal1> <non-terminal1>
+<?xml version='1.0' encoding='utf-8' ?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><title>CQL</title></head><body><p><link rel="StyleSheet" href="CQL.css" type="text/css" media="screen"></p><h1 id="CassandraQueryLanguageCQLv3.1.1">Cassandra Query Language (CQL) v3.1.1</h1><span id="tableOfContents"><ol style="list-style: none;"><li><a href="CQL.html#CassandraQueryLanguageCQLv3.1.1">Cassandra Query Language (CQL) v3.1.1</a><ol style="list-style: none;"><li><a href="CQL.html#CQLSyntax">CQL Syntax</a><ol style="list-style: none;"><li><a href="CQL.html#Preamble">Preamble</a></li><li><a href="CQL.html#Conventions">Conventions</a></li><li><a href="CQL.html#identifiers">Identifiers and keywords</a></li><li><a href="CQL.html#constants">Constants</a></li><li><a href="CQL.html#Comments">Comments</a></l
i><li><a href="CQL.html#statements">Statements</a></li><li><a href="CQL.html#preparedStatement">Prepared Statement</a></li></ol></li><li><a href="CQL.html#dataDefinition">Data Definition</a><ol style="list-style: none;"><li><a href="CQL.html#createKeyspaceStmt">CREATE KEYSPACE</a></li><li><a href="CQL.html#useStmt">USE</a></li><li><a href="CQL.html#alterKeyspaceStmt">ALTER KEYSPACE</a></li><li><a href="CQL.html#dropKeyspaceStmt">DROP KEYSPACE</a></li><li><a href="CQL.html#createTableStmt">CREATE TABLE</a></li><li><a href="CQL.html#alterTableStmt">ALTER TABLE</a></li><li><a href="CQL.html#dropTableStmt">DROP TABLE</a></li><li><a href="CQL.html#truncateStmt">TRUNCATE</a></li><li><a href="CQL.html#createIndexStmt">CREATE INDEX</a></li><li><a href="CQL.html#dropIndexStmt">DROP INDEX</a></li></ol></li><li><a href="CQL.html#dataManipulation">Data Manipulation</a><ol style="list-style: none;"><li><a href="CQL.html#insertStmt">INSERT</a></li><li><a href="CQL.html#updateStmt">UPDATE</a></li>
<li><a href="CQL.html#deleteStmt">DELETE</a></li><li><a href="CQL.html#batchStmt">BATCH</a></li></ol></li><li><a href="CQL.html#queries">Queries</a><ol style="list-style: none;"><li><a href="CQL.html#selectStmt">SELECT</a></li></ol></li><li><a href="CQL.html#types">Data Types</a><ol style="list-style: none;"><li><a href="CQL.html#usingdates">Working with dates</a></li><li><a href="CQL.html#counters">Counters</a></li><li><a href="CQL.html#collections">Working with collections</a></li></ol></li><li><a href="CQL.html#functions">Functions</a><ol style="list-style: none;"><li><a href="CQL.html#tokenFun">Token</a></li><li><a href="CQL.html#timeuuidFun">Timeuuid functions</a></li><li><a href="CQL.html#blobFun">Blob conversion functions</a></li></ol></li><li><a href="CQL.html#appendixA">Appendix A: CQL Keywords</a></li><li><a href="CQL.html#changes">Changes</a><ol style="list-style: none;"><li><a href="CQL.html#a3.1.1">3.1.1</a></li><li><a href="CQL.html#a3.1.0">3.1.0</a></li><li><a href="C
QL.html#a3.0.5">3.0.5</a></li><li><a href="CQL.html#a3.0.4">3.0.4</a></li><li><a href="CQL.html#a3.0.3">3.0.3</a></li><li><a href="CQL.html#a3.0.2">3.0.2</a></li><li><a href="CQL.html#a3.0.1">3.0.1</a></li></ol></li><li><a href="CQL.html#Versioning">Versioning</a></li></ol></li></ol></span><h2 id="CQLSyntax">CQL Syntax</h2><h3 id="Preamble">Preamble</h3><p>This document describes the Cassandra Query Language (CQL) version 3. CQL v3 is not backward compatible with CQL v2 and differs from it in numerous ways. Note that this document describes the last version of the languages. However, the <a href="#changes">changes</a> section provides the diff between the different versions of CQL v3.</p><p>CQL v3 offers a model very close to SQL in the sense that data is put in <em>tables</em> containing <em>rows</em> of <em>columns</em>. For that reason, when used in this document, these terms (tables, rows and columns) have the same definition than they have in SQL. But please note that as such,
they do <strong>not</strong> refer to the concept of rows and columns found in the internal implementation of Cassandra and in the thrift and CQL v2 API.</p><h3 id="Conventions">Conventions</h3><p>To aid in specifying the CQL syntax, we will use the following conventions in this document:</p><ul><li>Language rules will be given in a <a href="http://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form">BNF</a> -like notation:</li></ul><pre class="syntax"><pre><start> ::= TERMINAL <non-terminal1> <non-terminal1>
</pre></pre><ul><li>Nonterminal symbols will have <code><angle brackets></code>.</li><li>As additional shortcut notations to BNF, we’ll use traditional regular expression’s symbols (<code>?</code>, <code>+</code> and <code>*</code>) to signify that a given symbol is optional and/or can be repeated. We’ll also allow parentheses to group symbols and the <code>[<characters>]</code> notation to represent any one of <code><characters></code>.</li><li>The grammar is provided for documentation purposes and leave some minor details out. For instance, the last column definition in a <code>CREATE TABLE</code> statement is optional but supported if present even though the provided grammar in this document suggest it is not supported. </li><li>Sample code will be provided in a code block:</li></ul><pre class="sample"><pre>SELECT sample_usage FROM cql;
</pre></pre><ul><li>References to keywords or pieces of CQL code in running text will be shown in a <code>fixed-width font</code>.</li></ul><h3 id="identifiers">Identifiers and keywords</h3><p>The CQL language uses <em>identifiers</em> (or <em>names</em>) to identify tables, columns and other objects. An identifier is a token matching the regular expression <code lang="a-zA-Z">[a-zA-Z0-9_]</code><code>*</code>.</p><p>A number of such identifiers, like <code>SELECT</code> or <code>WITH</code>, are <em>keywords</em>. They have a fixed meaning for the language and most are reserved. The list of those keywords can be found in <a href="#appendixA">Appendix A</a>.</p><p>Identifiers and (unquoted) keywords are case insensitive. Thus <code>SELECT</code> is the same than <code>select</code> or <code>sElEcT</code>, and <code>myId</code> is the same than <code>myid</code> or <code>MYID</code> for instance. A convention often used (in particular by the samples of this documentation) is to use u
pper case for keywords and lower case for other identifiers.</p><p>There is a second kind of identifiers called <em>quoted identifiers</em> defined by enclosing an arbitrary sequence of characters in double-quotes(<code>"</code>). Quoted identifiers are never keywords. Thus <code>"select"</code> is not a reserved keyword and can be used to refer to a column, while <code>select</code> would raise a parse error. Also, contrarily to unquoted identifiers and keywords, quoted identifiers are case sensitive (<code>"My Quoted Id"</code> is <em>different</em> from <code>"my quoted id"</code>). A fully lowercase quoted identifier that matches <code lang="a-zA-Z">[a-zA-Z0-9_]</code><code>*</code> is equivalent to the unquoted identifier obtained by removing the double-quote (so <code>"myid"</code> is equivalent to <code>myid</code> and to <code>myId</code> but different from <code>"myId"</code>). Inside a quoted identifier, the double-quote character can be repeated to escape it, so <code>"fo
o "" bar"</code> is a valid identifier.</p><h3 id="constants">Constants</h3><p>CQL defines the following kind of <em>constants</em>: strings, integers, floats, booleans, uuids and blobs:</p><ul><li>A string constant is an arbitrary sequence of characters characters enclosed by single-quote(<code>'</code>). One can include a single-quote in a string by repeating it, e.g. <code>'It''s raining today'</code>. Those are not to be confused with quoted identifiers that use double-quotes.</li><li>An integer constant is defined by <code>'-'?[0-9]+</code>.</li><li>A float constant is defined by <code>'-'?[0-9]+('.'[0-9]*)?([eE][+-]?[0-9+])?</code>.</li><li>A boolean constant is either <code>true</code> or <code>false</code> up to case-insensitivity (i.e. <code>True</code> is a valid boolean constant).</li><li>A <a href="http://en.wikipedia.org/wiki/Universally_unique_identifier">UUID</a> constant is defined by <code>hex{8}-hex{4}-hex{4}-hex{4}-hex{12}</code> where <code>hex</code> is an hexad
ecimal character, e.g. <code>[0-9a-fA-F]</code> and <code>{4}</code> is the number of such characters.</li><li>A blob constant is an hexadecimal number defined by <code>0[xX](hex)+</code> where <code>hex</code> is an hexadecimal character, e.g. <code>[0-9a-fA-F]</code>.</li></ul><p>For how these constants are typed, see the <a href="#types">data types section</a>.</p><h3 id="Comments">Comments</h3><p>A comment in CQL is a line beginning by either double dashes (<code>--</code>) or double slash (<code>//</code>).</p><p>Multi-line comments are also supported through enclosure withing <code>/*</code> and <code>*/</code> (but nesting is not supported).</p><pre class="sample"><pre>-- This is a comment
// This is a comment too
@@ -93,7 +93,7 @@ CREATE TABLE timeline (
other text,
PRIMARY KEY (k)
)
-</pre></pre><p>Moreover, a table must define at least one column that is not part of the PRIMARY KEY as a row exists in Cassandra only if it contains at least one value for one such column.</p><h4 id="createTablepartitionClustering">Partition key and clustering</h4><p>In CQL, the order in which columns are defined for the <code>PRIMARY KEY</code> matters. The first column of the key is called the <i>partition key</i>. It has the property that all the rows sharing the same partition key (even across table in fact) are stored on the same physical node. Also, insertion/update/deletion on rows sharing the same partition key for a given table are performed <i>atomically</i> and in <i>isolation</i>. Note that it is possible to have a composite partition key, i.e. a partition key formed of multiple columns, using an extra set of parentheses to define which columns forms the partition key.</p><p>The remaining columns of the <code>PRIMARY KEY</code> definition, if any, are called <i>clusteri
ng keys</i>. On a given physical node, rows for a given partition key are stored in the order induced by the clustering keys, making the retrieval of rows in that clustering order particularly efficient (see <a href="#selectStmt"><tt>SELECT</tt></a>).</p><h4 id="createTableOptions"><code><option></code></h4><p>The <code>CREATE TABLE</code> statement supports a number of options that controls the configuration of a new table. These options can be specified after the <code>WITH</code> keyword.</p><p>The first of these option is <code>COMPACT STORAGE</code>. This option is meanly targeted towards backward compatibility with some table definition created before CQL3. But it also provides a slightly more compact layout of data on disk, though at the price of flexibility and extensibility, and for that reason is not recommended unless for the backward compatibility reason. The restriction for table with <code>COMPACT STORAGE</code> is that they support one and only one column outside
of the ones part of the <code>PRIMARY KEY</code>. It also follows that columns cannot be added nor removed after creation. A table with <code>COMPACT STORAGE</code> must also define at least one <a href="createTablepartitionClustering">clustering key</a>.</p><p>Another option is <code>CLUSTERING ORDER</code>. It allows to define the ordering of rows on disk. It takes the list of the clustering key names with, for each of them, the on-disk order (Ascending or descending). Note that this option affects <a href="#selectOrderBy">what <code>ORDER BY</code> are allowed during <code>SELECT</code></a>.</p><p>Table creation supports the following other <code><property></code>:</p><table><tr><th>option </th><th>kind </th><th>default </th><th>description</th></tr><tr><td><code>comment</code> </td><td><em>simple</em> </td><td>none </td><td>A free-form, human-readable comment.</td></tr><tr><td><code>read_repair_chance</code> </td><td><e
m>simple</em> </td><td>0.1 </td><td>The probability with which to query extra nodes (e.g. more nodes than required by the consistency level) for the purpose of read repairs.</td></tr><tr><td><code>dclocal_read_repair_chance</code> </td><td><em>simple</em> </td><td>0 </td><td>The probability with which to query extra nodes (e.g. more nodes than required by the consistency level) belonging to the same data center than the read coordinator for the purpose of read repairs.</td></tr><tr><td><code>gc_grace_seconds</code> </td><td><em>simple</em> </td><td>864000 </td><td>Time to wait before garbage collecting tombstones (deletion markers).</td></tr><tr><td><code>bloom_filter_fp_chance</code> </td><td><em>simple</em> </td><td>0.00075 </td><td>The target probability of false positive of the sstable bloom filters. Said bloom filters will be sized to provide the provided probability (thus lowering this value impact the size of bloom filters in-memory an
d on-disk)</td></tr><tr><td><code>compaction</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>The compaction otpions to use, see below.</td></tr><tr><td><code>compression</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>Compression options, see below. </td></tr><tr><td><code>replicate_on_write</code> </td><td><em>simple</em> </td><td>true </td><td>Whether to replicate data on write. This can only be set to false for tables with counters values. Disabling this is dangerous and can result in random lose of counters, don’t disable unless you are sure to know what you are doing</td></tr><tr><td><code>caching</code> </td><td><em>simple</em> </td><td>keys_only </td><td>Whether to cache keys (“key cache”) and/or rows (“row cache”) for this table. Valid values are: <code>all</code>, <code>keys_only</code>, <code>rows_only</code> and <code>none</code>. </td
></tr></table><h4 id="compactionOptions"><code>compaction</code> options</h4><p>The <code>compaction</code> property must at least define the <code>'class'</code> sub-option, that defines the compaction strategy class to use. The default supported class are <code>'SizeTieredCompactionStrategy'</code> and <code>'LeveledCompactionStrategy'</code>. Custom strategy can be provided by specifying the full class name as a <a href="#constants">string constant</a>. The rest of the sub-options depends on the chosen class. The sub-options supported by the default classes are:</p><table><tr><th>option </th><th>supported compaction strategy </th><th>default </th><th>description </th></tr><tr><td><code>tombstone_threshold</code> </td><td><em>all</em> </td><td>0.2 </td><td>A ratio such that if a sstable has more than this ratio of gcable tombstones over all contained columns, the sstable will be compacted (with no other sstables) for
the purpose of purging those tombstones. </td></tr><tr><td><code>tombstone_compaction_interval</code> </td><td><em>all</em> </td><td>1 day </td><td>The mininum time to wait after an sstable creation time before considering it for “tombstone compaction”, where “tombstone compaction” is the compaction triggered if the sstable has more gcable tombstones than <code>tombstone_threshold</code>. </td></tr><tr><td><code>min_sstable_size</code> </td><td>SizeTieredCompactionStrategy </td><td>50MB </td><td>The size tiered strategy groups SSTables to compact in buckets. A bucket groups SSTables that differs from less than 50% in size. However, for small sizes, this would result in a bucketing that is too fine grained. <code>min_sstable_size</code> defines a size threshold (in bytes) below which all SSTables belong to one unique bucket</td></tr><tr><td><code>min_threshold</code> </td><td>SizeTieredCompac
tionStrategy </td><td>4 </td><td>Minimum number of SSTables needed to start a minor compaction.</td></tr><tr><td><code>max_threshold</code> </td><td>SizeTieredCompactionStrategy </td><td>32 </td><td>Maximum number of SSTables processed by one minor compaction.</td></tr><tr><td><code>bucket_low</code> </td><td>SizeTieredCompactionStrategy </td><td>0.5 </td><td>Size tiered consider sstables to be within the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose sizes diverges by at most 50%)</td></tr><tr><td><code>bucket_high</code> </td><td>SizeTieredCompactionStrategy </td><td>1.5 </td><td>Size tiered consider sstables to be within the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose si
zes diverges by at most 50%).</td></tr><tr><td><code>sstable_size_in_mb</code> </td><td>LeveledCompactionStrategy </td><td>5MB </td><td>The target size (in MB) for sstables in the leveled strategy. Note that while sstable sizes should stay less or equal to <code>sstable_size_in_mb</code>, it is possible to exceptionally have a larger sstable as during compaction, data for a given partition key are never split into 2 sstables</td></tr></table><p>For the <code>compression</code> property, the following default sub-options are available:</p><table><tr><th>option </th><th>default </th><th>description </th></tr><tr><td><code>sstable_compression</code> </td><td>SnappyCompressor </td><td>The compression algorithm to use. Default compressor are: SnappyCompressor and DeflateCompressor. Use an empty string (<code>''</code>) to disable compression. Custom compressor can be provided by specifying the full class name as a <a href="#constants">string con
stant</a>.</td></tr><tr><td><code>chunk_length_kb</code> </td><td>64KB </td><td>On disk SSTables are compressed by block (to allow random reads). This defines the size (in KB) of said block. Bigger values may improve the compression rate, but increases the minimum size of data to be read from disk for a read </td></tr><tr><td><code>crc_check_chance</code> </td><td>1.0 </td><td>When compression is enabled, each compressed block includes a checksum of that block for the purpose of detecting disk bitrot and avoiding the propagation of corruption to other replica. This option defines the probability with which those checksums are checked during read. By default they are always checked. Set to 0 to disable checksum checking and to 0.5 for instance to check them every other read</td></tr></table><h4 id="Otherconsiderations">Other considerations:</h4><ul><li>When <a href="#insertStmt/"updating":#updateStmt">inserting</a> a given row, not all column
s needs to be defined (except for those part of the key), and missing columns occupy no space on disk. Furthermore, adding new columns (see <a href=#alterStmt><tt>ALTER TABLE</tt></a>) is a constant time operation. There is thus no need to try to anticipate future usage (or to cry when you haven’t) when creating a table.</li></ul><h3 id="alterTableStmt">ALTER TABLE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><alter-table-stmt> ::= ALTER (TABLE | COLUMNFAMILY) <tablename> <instruction>
+</pre></pre><p>Moreover, a table must define at least one column that is not part of the PRIMARY KEY as a row exists in Cassandra only if it contains at least one value for one such column.</p><h4 id="createTablepartitionClustering">Partition key and clustering</h4><p>In CQL, the order in which columns are defined for the <code>PRIMARY KEY</code> matters. The first column of the key is called the <i>partition key</i>. It has the property that all the rows sharing the same partition key (even across table in fact) are stored on the same physical node. Also, insertion/update/deletion on rows sharing the same partition key for a given table are performed <i>atomically</i> and in <i>isolation</i>. Note that it is possible to have a composite partition key, i.e. a partition key formed of multiple columns, using an extra set of parentheses to define which columns forms the partition key.</p><p>The remaining columns of the <code>PRIMARY KEY</code> definition, if any, are called __clusterin
g columns. On a given physical node, rows for a given partition key are stored in the order induced by the clustering columns, making the retrieval of rows in that clustering order particularly efficient (see <a href="#selectStmt"><tt>SELECT</tt></a>).</p><h4 id="createTableOptions"><code><option></code></h4><p>The <code>CREATE TABLE</code> statement supports a number of options that controls the configuration of a new table. These options can be specified after the <code>WITH</code> keyword.</p><p>The first of these option is <code>COMPACT STORAGE</code>. This option is meanly targeted towards backward compatibility with some table definition created before CQL3. But it also provides a slightly more compact layout of data on disk, though at the price of flexibility and extensibility, and for that reason is not recommended unless for the backward compatibility reason. The restriction for table with <code>COMPACT STORAGE</code> is that they support one and only one column outside
of the ones part of the <code>PRIMARY KEY</code>. It also follows that columns cannot be added nor removed after creation. A table with <code>COMPACT STORAGE</code> must also define at least one <a href="createTablepartitionClustering">clustering key</a>.</p><p>Another option is <code>CLUSTERING ORDER</code>. It allows to define the ordering of rows on disk. It takes the list of the clustering key names with, for each of them, the on-disk order (Ascending or descending). Note that this option affects <a href="#selectOrderBy">what <code>ORDER BY</code> are allowed during <code>SELECT</code></a>.</p><p>Table creation supports the following other <code><property></code>:</p><table><tr><th>option </th><th>kind </th><th>default </th><th>description</th></tr><tr><td><code>comment</code> </td><td><em>simple</em> </td><td>none </td><td>A free-form, human-readable comment.</td></tr><tr><td><code>read_repair_chance</code> </td><td><
em>simple</em> </td><td>0.1 </td><td>The probability with which to query extra nodes (e.g. more nodes than required by the consistency level) for the purpose of read repairs.</td></tr><tr><td><code>dclocal_read_repair_chance</code> </td><td><em>simple</em> </td><td>0 </td><td>The probability with which to query extra nodes (e.g. more nodes than required by the consistency level) belonging to the same data center than the read coordinator for the purpose of read repairs.</td></tr><tr><td><code>gc_grace_seconds</code> </td><td><em>simple</em> </td><td>864000 </td><td>Time to wait before garbage collecting tombstones (deletion markers).</td></tr><tr><td><code>bloom_filter_fp_chance</code> </td><td><em>simple</em> </td><td>0.00075 </td><td>The target probability of false positive of the sstable bloom filters. Said bloom filters will be sized to provide the provided probability (thus lowering this value impact the size of bloom filters in-memory a
nd on-disk)</td></tr><tr><td><code>compaction</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>The compaction otpions to use, see below.</td></tr><tr><td><code>compression</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>Compression options, see below. </td></tr><tr><td><code>replicate_on_write</code> </td><td><em>simple</em> </td><td>true </td><td>Whether to replicate data on write. This can only be set to false for tables with counters values. Disabling this is dangerous and can result in random lose of counters, don’t disable unless you are sure to know what you are doing</td></tr><tr><td><code>caching</code> </td><td><em>simple</em> </td><td>keys_only </td><td>Whether to cache keys (“key cache”) and/or rows (“row cache”) for this table. Valid values are: <code>all</code>, <code>keys_only</code>, <code>rows_only</code> and <code>none</code>. </t
d></tr></table><h4 id="compactionOptions"><code>compaction</code> options</h4><p>The <code>compaction</code> property must at least define the <code>'class'</code> sub-option, that defines the compaction strategy class to use. The default supported class are <code>'SizeTieredCompactionStrategy'</code> and <code>'LeveledCompactionStrategy'</code>. Custom strategy can be provided by specifying the full class name as a <a href="#constants">string constant</a>. The rest of the sub-options depends on the chosen class. The sub-options supported by the default classes are:</p><table><tr><th>option </th><th>supported compaction strategy </th><th>default </th><th>description </th></tr><tr><td><code>tombstone_threshold</code> </td><td><em>all</em> </td><td>0.2 </td><td>A ratio such that if a sstable has more than this ratio of gcable tombstones over all contained columns, the sstable will be compacted (with no other sstables) fo
r the purpose of purging those tombstones. </td></tr><tr><td><code>tombstone_compaction_interval</code> </td><td><em>all</em> </td><td>1 day </td><td>The mininum time to wait after an sstable creation time before considering it for “tombstone compaction”, where “tombstone compaction” is the compaction triggered if the sstable has more gcable tombstones than <code>tombstone_threshold</code>. </td></tr><tr><td><code>min_sstable_size</code> </td><td>SizeTieredCompactionStrategy </td><td>50MB </td><td>The size tiered strategy groups SSTables to compact in buckets. A bucket groups SSTables that differs from less than 50% in size. However, for small sizes, this would result in a bucketing that is too fine grained. <code>min_sstable_size</code> defines a size threshold (in bytes) below which all SSTables belong to one unique bucket</td></tr><tr><td><code>min_threshold</code> </td><td>SizeTieredCompa
ctionStrategy </td><td>4 </td><td>Minimum number of SSTables needed to start a minor compaction.</td></tr><tr><td><code>max_threshold</code> </td><td>SizeTieredCompactionStrategy </td><td>32 </td><td>Maximum number of SSTables processed by one minor compaction.</td></tr><tr><td><code>bucket_low</code> </td><td>SizeTieredCompactionStrategy </td><td>0.5 </td><td>Size tiered consider sstables to be within the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose sizes diverges by at most 50%)</td></tr><tr><td><code>bucket_high</code> </td><td>SizeTieredCompactionStrategy </td><td>1.5 </td><td>Size tiered consider sstables to be within the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose s
izes diverges by at most 50%).</td></tr><tr><td><code>sstable_size_in_mb</code> </td><td>LeveledCompactionStrategy </td><td>5MB </td><td>The target size (in MB) for sstables in the leveled strategy. Note that while sstable sizes should stay less or equal to <code>sstable_size_in_mb</code>, it is possible to exceptionally have a larger sstable as during compaction, data for a given partition key are never split into 2 sstables</td></tr></table><p>For the <code>compression</code> property, the following default sub-options are available:</p><table><tr><th>option </th><th>default </th><th>description </th></tr><tr><td><code>sstable_compression</code> </td><td>SnappyCompressor </td><td>The compression algorithm to use. Default compressor are: SnappyCompressor and DeflateCompressor. Use an empty string (<code>''</code>) to disable compression. Custom compressor can be provided by specifying the full class name as a <a href="#constants">string co
nstant</a>.</td></tr><tr><td><code>chunk_length_kb</code> </td><td>64KB </td><td>On disk SSTables are compressed by block (to allow random reads). This defines the size (in KB) of said block. Bigger values may improve the compression rate, but increases the minimum size of data to be read from disk for a read </td></tr><tr><td><code>crc_check_chance</code> </td><td>1.0 </td><td>When compression is enabled, each compressed block includes a checksum of that block for the purpose of detecting disk bitrot and avoiding the propagation of corruption to other replica. This option defines the probability with which those checksums are checked during read. By default they are always checked. Set to 0 to disable checksum checking and to 0.5 for instance to check them every other read</td></tr></table><h4 id="Otherconsiderations">Other considerations:</h4><ul><li>When <a href="#insertStmt/"updating":#updateStmt">inserting</a> a given row, not all colum
ns needs to be defined (except for those part of the key), and missing columns occupy no space on disk. Furthermore, adding new columns (see <a href=#alterStmt><tt>ALTER TABLE</tt></a>) is a constant time operation. There is thus no need to try to anticipate future usage (or to cry when you haven’t) when creating a table.</li></ul><h3 id="alterTableStmt">ALTER TABLE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><alter-table-stmt> ::= ALTER (TABLE | COLUMNFAMILY) <tablename> <instruction>
<instruction> ::= ALTER <identifier> TYPE <type>
| ADD <identifier> <type>
@@ -108,7 +108,7 @@ ADD gravesite varchar;
ALTER TABLE addamsFamily
WITH comment = 'A most excellent and useful column family'
AND read_repair_chance = 0.2;
-</pre></pre><p><br/>The <code>ALTER</code> statement is used to manipulate table definitions. It allows to add new columns, drop existing ones, change the type of existing columns, or update the table options. As for table creation, <code>ALTER COLUMNFAMILY</code> is allowed as an alias for <code>ALTER TABLE</code>.</p><p>The <code><tablename></code> is the table name optionally preceded by the keyspace name. The <code><instruction></code> defines the alteration to perform:</p><ul><li><code>ALTER</code>: Update the type of a given defined column. Note that the type of the <a href="#createTablepartitionClustering">clustering keys</a> cannot be modified as it induces the on-disk ordering of rows. Columns on which a <a href="#createIndexStmt">secondary index</a> is defined have the same restriction. Other columns are free from those restrictions (no validation of existing data is performed), but it is usually a bad idea to change the type to a non-compatible one, unless no data
have been inserted for that column yet, as this could confuse CQL drivers/tools.</li><li><code>ADD</code>: Adds a new column to the table. The <code><identifier></code> for the new column must not conflict with an existing column. Moreover, columns cannot be added to tables defined with the <code>COMPACT STORAGE</code> option.</li><li><code>DROP</code>: Removes a column from the table. Dropped columns will immediately become unavailable in the queries and will not be included in compacted sstables in the future. If a column is readded, queries won’t return values written before the column was last dropped. It is assumed that timestamps represent actual time, so if this is not your case, you should NOT readd previously dropped columns. Columns can’t be dropped from tables defined with the <code>COMPACT STORAGE</code> option.</li><li><code>WITH</code>: Allows to update the options of the table. The <a href="#createTableOptions">supported <code><option></code></a> (an
d syntax) are the same as for the <code>CREATE TABLE</code> statement except that <code>COMPACT STORAGE</code> is not supported. Note that setting any <code>compaction</code> sub-options has the effect of erasing all previous <code>compaction</code> options, so you need to re-specify all the sub-options if you want to keep them. The same note applies to the set of <code>compression</code> sub-options.</li></ul><h3 id="dropTableStmt">DROP TABLE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><drop-table-stmt> ::= DROP TABLE ( IF EXISTS )? <tablename>
+</pre></pre><p><br/>The <code>ALTER</code> statement is used to manipulate table definitions. It allows to add new columns, drop existing ones, change the type of existing columns, or update the table options. As for table creation, <code>ALTER COLUMNFAMILY</code> is allowed as an alias for <code>ALTER TABLE</code>.</p><p>The <code><tablename></code> is the table name optionally preceded by the keyspace name. The <code><instruction></code> defines the alteration to perform:</p><ul><li><code>ALTER</code>: Update the type of a given defined column. Note that the type of the <a href="#createTablepartitionClustering">clustering columns</a> cannot be modified as it induces the on-disk ordering of rows. Columns on which a <a href="#createIndexStmt">secondary index</a> is defined have the same restriction. Other columns are free from those restrictions (no validation of existing data is performed), but it is usually a bad idea to change the type to a non-compatible one, unless no da
ta have been inserted for that column yet, as this could confuse CQL drivers/tools.</li><li><code>ADD</code>: Adds a new column to the table. The <code><identifier></code> for the new column must not conflict with an existing column. Moreover, columns cannot be added to tables defined with the <code>COMPACT STORAGE</code> option.</li><li><code>DROP</code>: Removes a column from the table. Dropped columns will immediately become unavailable in the queries and will not be included in compacted sstables in the future. If a column is readded, queries won’t return values written before the column was last dropped. It is assumed that timestamps represent actual time, so if this is not your case, you should NOT readd previously dropped columns. Columns can’t be dropped from tables defined with the <code>COMPACT STORAGE</code> option.</li><li><code>WITH</code>: Allows to update the options of the table. The <a href="#createTableOptions">supported <code><option></code></a>
(and syntax) are the same as for the <code>CREATE TABLE</code> statement except that <code>COMPACT STORAGE</code> is not supported. Note that setting any <code>compaction</code> sub-options has the effect of erasing all previous <code>compaction</code> options, so you need to re-specify all the sub-options if you want to keep them. The same note applies to the set of <code>compression</code> sub-options.</li></ul><h3 id="dropTableStmt">DROP TABLE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><drop-table-stmt> ::= DROP TABLE ( IF EXISTS )? <tablename>
</pre></pre><p><i>Sample:</i></p><pre class="sample"><pre>DROP TABLE worldSeriesAttendees;
</pre></pre><p>The <code>DROP TABLE</code> statement results in the immediate, irreversible removal of a table, including all data contained in it. As for table creation, <code>DROP COLUMNFAMILY</code> is allowed as an alias for <code>DROP TABLE</code>.</p><p>If the table does not exists, the statement will return an error, unless <code>IF EXISTS</code> is used in which case the operation is a no-op.</p><h3 id="truncateStmt">TRUNCATE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><truncate-stmt> ::= TRUNCATE <tablename>
</pre></pre><p><i>Sample:</i></p><pre class="sample"><pre>TRUNCATE superImportantData;
@@ -195,7 +195,7 @@ APPLY BATCH;
( LIMIT <integer> )?
( ALLOW FILTERING )?
-<select-clause> ::= <selection-list>
+<select-clause> ::= DISTINCT? <selection-list>
| COUNT '(' ( '*' | '1' ) ')' (AS <identifier>)?
<selection-list> ::= <selector> (AS <identifier>)? ( ',' <selector> (AS <identifier>)? )*
@@ -228,7 +228,7 @@ SELECT COUNT(*) FROM users;
SELECT COUNT(*) AS user_count FROM users;
-</pre></pre><p><br/>The <code>SELECT</code> statements reads one or more columns for one or more rows in a table. It returns a result-set of rows, where each row contains the collection of columns corresponding to the query.</p><h4 id="selectSelection"><code><select-clause></code></h4><p>The <code><select-clause></code> determines which columns needs to be queried and returned in the result-set. It consists of either the comma-separated list of <selector> or the wildcard character (<code>*</code>) to select all the columns defined for the table.</p><p>A <code><selector></code> is either a column name to retrieve, or a <code><function></code> of one or multiple column names. The functions allows are the same that for <code><term></code> and are describe in the <a href="#function">function section</a>. In addition to these generic functions, the <code>WRITETIME</code> (resp. <code>TTL</code>) function allows to select the timestamp of when the column was inserted (resp.
the time to live (in seconds) for the column (or null if the column has no expiration set)).</p><p>Any <code><selector></code> can be aliased using <code>AS</code> keyword (see examples). Please note that <code><where-clause></code> and <code><order-by></code> clause should refer to the columns by their original names and not by their aliases.</p><p>The <code>COUNT</code> keyword can be used with parenthesis enclosing <code>*</code>. If so, the query will return a single result: the number of rows matching the query. Note that <code>COUNT(1)</code> is supported as an alias.</p><h4 id="selectWhere"><code><where-clause></code></h4><p>The <code><where-clause></code> specifies which rows must be queried. It is composed of relations on the columns that are part of the <code>PRIMARY KEY</code> and/or have a <a href="#createIndexStmt">secondary index</a> defined on them.</p><p>Not all relations are allowed in a query. For instance, non-equal relations (where <code>IN</code>
is considered as an equal relation) on a partition key are not supported (but see the use of the <code>TOKEN</code> method below to do non-equal queries on the partition key). Moreover, for a given partition key, the clustering keys induce an ordering of rows and relations on them is restricted to the relations that allow to select a <strong>contiguous</strong> (for the ordering) set of rows. For instance, given</p><pre class="sample"><pre>CREATE TABLE posts (
+</pre></pre><p><br/>The <code>SELECT</code> statements reads one or more columns for one or more rows in a table. It returns a result-set of rows, where each row contains the collection of columns corresponding to the query.</p><h4 id="selectSelection"><code><select-clause></code></h4><p>The <code><select-clause></code> determines which columns needs to be queried and returned in the result-set. It consists of either the comma-separated list of <selector> or the wildcard character (<code>*</code>) to select all the columns defined for the table.</p><p>A <code><selector></code> is either a column name to retrieve, or a <code><function></code> of one or multiple column names. The functions allows are the same that for <code><term></code> and are describe in the <a href="#function">function section</a>. In addition to these generic functions, the <code>WRITETIME</code> (resp. <code>TTL</code>) function allows to select the timestamp of when the column was inserted (resp.
the time to live (in seconds) for the column (or null if the column has no expiration set)).</p><p>Any <code><selector></code> can be aliased using <code>AS</code> keyword (see examples). Please note that <code><where-clause></code> and <code><order-by></code> clause should refer to the columns by their original names and not by their aliases.</p><p>The <code>COUNT</code> keyword can be used with parenthesis enclosing <code>*</code>. If so, the query will return a single result: the number of rows matching the query. Note that <code>COUNT(1)</code> is supported as an alias.</p><h4 id="selectWhere"><code><where-clause></code></h4><p>The <code><where-clause></code> specifies which rows must be queried. It is composed of relations on the columns that are part of the <code>PRIMARY KEY</code> and/or have a <a href="#createIndexStmt">secondary index</a> defined on them.</p><p>Not all relations are allowed in a query. For instance, non-equal relations (where <code>IN</code>
is considered as an equal relation) on a partition key are not supported (but see the use of the <code>TOKEN</code> method below to do non-equal queries on the partition key). Moreover, for a given partition key, the clustering columns induce an ordering of rows and relations on them is restricted to the relations that allow to select a <strong>contiguous</strong> (for the ordering) set of rows. For instance, given</p><pre class="sample"><pre>CREATE TABLE posts (
userid text,
blog_title text,
posted_at timestamp,
@@ -323,4 +323,4 @@ UPDATE plays SET scores = scores - [ 12,
)
</pre></pre><p>then the <code>token</code> function will take a single argument of type <code>text</code> (in that case, the partition key is <code>userid</code> (there is no clustering key so the partition key is the same than the primary key)), and the return type will be <code>bigint</code>.</p><h3 id="timeuuidFun">Timeuuid functions</h3><h4 id="now"><code>now</code></h4><p>The <code>now</code> function takes no arguments and generates a new unique timeuuid (at the time where the statement using it is executed). Note that this method is useful for insertion but is largely non-sensical in <code>WHERE</code> clauses. For instance, a query of the form</p><pre class="sample"><pre>SELECT * FROM myTable WHERE t = now()
</pre></pre><p>will never return any result by design, since the value returned by <code>now()</code> is guaranteed to be unique.</p><h4 id="minTimeuuidandmaxTimeuuid"><code>minTimeuuid</code> and <code>maxTimeuuid</code></h4><p>The <code>minTimeuuid</code> (resp. <code>maxTimeuuid</code>) function takes a <code>timestamp</code> value <code>t</code> (which can be <a href="#usingdates">either a timestamp or a date string</a>) and return a <em>fake</em> <code>timeuuid</code> corresponding to the <em>smallest</em> (resp. <em>biggest</em>) possible <code>timeuuid</code> having for timestamp <code>t</code>. So for instance:</p> <pre class="sample"><pre>SELECT * FROM myTable WHERE t > maxTimeuuid('2013-01-01 00:05+0000') AND t < minTimeuuid('2013-02-02 10:00+0000')
-</pre></pre> <p>will select all rows where the <code>timeuuid</code> column <code>t</code> is strictly older than ‘2013-01-01 00:05+0000’ but stricly younger than ‘2013-02-02 10:00+0000’. Please note that <code>t >= maxTimeuuid('2013-01-01 00:05+0000')</code> would still <em>not</em> select a <code>timeuuid</code> generated exactly at ‘2013-01-01 00:05+0000’ and is essentially equivalent to <code>t > maxTimeuuid('2013-01-01 00:05+0000')</code>.</p><p><em>Warning</em>: We called the values generated by <code>minTimeuuid</code> and <code>maxTimeuuid</code> <em>fake</em> UUID because they do no respect the Time-Based UUID generation process specified by the <a href="http://www.ietf.org/rfc/rfc4122.txt">RFC 4122</a>. In particular, the value returned by these 2 methods will not be unique. This means you should only use those methods for querying (as in the example above). Inserting the result of those methods is almost certainly <em>a bad idea</em>.<
/p><h4 id="dateOfandunixTimestampOf"><code>dateOf</code> and <code>unixTimestampOf</code></h4><p>The <code>dateOf</code> and <code>unixTimestampOf</code> functions take a <code>timeuuid</code> argument and extract the embeded timestamp. However, while the <code>dateof</code> function return it with the <code>timestamp</code> type (that most client, including cqlsh, interpret as a date), the <code>unixTimestampOf</code> function returns it as a <code>bigint</code> raw value.</p><h3 id="blobFun">Blob conversion functions</h3><p>A number of functions are provided to “convert” the native types into binary data (<code>blob</code>). For every <code><native-type></code> <code>type</code> supported by CQL3 (a notable exceptions is <code>blob</code>, for obvious reasons), the function <code>typeAsBlob</code> takes a argument of type <code>type</code> and return it as a <code>blob</code>. Conversely, the function <code>blobAsType</code> takes a 64-bit <code>blob</code> argumen
t and convert it to a <code>bigint</code> value. And so for instance, <code>bigintAsBlob(3)</code> is <code>0x0000000000000003</code> and <code>blobAsBigint(0x0000000000000003)</code> is <code>3</code>.</p><h2 id="appendixA">Appendix A: CQL Keywords</h2><p>CQL distinguishes between <em>reserved</em> and <em>non-reserved</em> keywords. Reserved keywords cannot be used as identifier, they are truly reserved for the language (but one can enclose a reserved keyword by double-quotes to use it as an identifier). Non-reserved keywords however only have a specific meaning in certain context but can used as identifer otherwise. The only <em>raison d'être</em> of these non-reserved keywords is convenience: some keyword are non-reserved when it was always easy for the parser to decide whether they were used as keywords or not.</p><table><tr><th>Keyword </th><th>Reserved? </th></tr><tr><td><code>ADD</code> </td><td>yes </td></tr><tr><td><code>ALL</code> </td><td>no <
/td></tr><tr><td><code>ALTER</code> </td><td>yes </td></tr><tr><td><code>AND</code> </td><td>yes </td></tr><tr><td><code>ANY</code> </td><td>yes </td></tr><tr><td><code>APPLY</code> </td><td>yes </td></tr><tr><td><code>AS</code> </td><td>no </td></tr><tr><td><code>ASC</code> </td><td>yes </td></tr><tr><td><code>ASCII</code> </td><td>no </td></tr><tr><td><code>AUTHORIZE</code> </td><td>yes </td></tr><tr><td><code>BATCH</code> </td><td>yes </td></tr><tr><td><code>BEGIN</code> </td><td>yes </td></tr><tr><td><code>BIGINT</code> </td><td>no </td></tr><tr><td><code>BLOB</code> </td><td>no </td></tr><tr><td><code>BOOLEAN</code> </td><td>no </td></tr><tr><td><code>BY</code> </td><td>yes </td></tr><tr><td><code>CLUSTERING</code> </td><td>no </td></tr><tr><td><code>COLUMNFAMILY</code> </td><td>yes </td></tr><tr><td><code>COMPACT</code> </td><td>no </td></tr><tr><td><code>CONSI
STENCY</code> </td><td>no </td></tr><tr><td><code>COUNT</code> </td><td>no </td></tr><tr><td><code>COUNTER</code> </td><td>no </td></tr><tr><td><code>CREATE</code> </td><td>yes </td></tr><tr><td><code>DECIMAL</code> </td><td>no </td></tr><tr><td><code>DELETE</code> </td><td>yes </td></tr><tr><td><code>DESC</code> </td><td>yes </td></tr><tr><td><code>DOUBLE</code> </td><td>no </td></tr><tr><td><code>DROP</code> </td><td>yes </td></tr><tr><td><code>EACH_QUORUM</code> </td><td>yes </td></tr><tr><td><code>FLOAT</code> </td><td>no </td></tr><tr><td><code>FROM</code> </td><td>yes </td></tr><tr><td><code>GRANT</code> </td><td>yes </td></tr><tr><td><code>IN</code> </td><td>yes </td></tr><tr><td><code>INDEX</code> </td><td>yes </td></tr><tr><td><code>CUSTOM</code> </td><td>no </td></tr><tr><td><code>INSERT</code> </td><td>yes </td></tr><tr><td><code>INT</code> </td><td>no
</td></tr><tr><td><code>INTO</code> </td><td>yes </td></tr><tr><td><code>KEY</code> </td><td>no </td></tr><tr><td><code>KEYSPACE</code> </td><td>yes </td></tr><tr><td><code>LEVEL</code> </td><td>no </td></tr><tr><td><code>LIMIT</code> </td><td>yes </td></tr><tr><td><code>LOCAL_QUORUM</code> </td><td>yes </td></tr><tr><td><code>MODIFY</code> </td><td>yes </td></tr><tr><td><code>NORECURSIVE</code> </td><td>yes </td></tr><tr><td><code>NOSUPERUSER</code> </td><td>no </td></tr><tr><td><code>OF</code> </td><td>yes </td></tr><tr><td><code>ON</code> </td><td>yes </td></tr><tr><td><code>ONE</code> </td><td>yes </td></tr><tr><td><code>ORDER</code> </td><td>yes </td></tr><tr><td><code>PASSWORD</code> </td><td>no </td></tr><tr><td><code>PERMISSION</code> </td><td>no </td></tr><tr><td><code>PERMISSIONS</code> </td><td>no </td></tr><tr><td><code>PRIMARY</code> </td><td>yes </td></tr><tr><td><code>QUOR
UM</code> </td><td>yes </td></tr><tr><td><code>REVOKE</code> </td><td>yes </td></tr><tr><td><code>SCHEMA</code> </td><td>yes </td></tr><tr><td><code>SELECT</code> </td><td>yes </td></tr><tr><td><code>SET</code> </td><td>yes </td></tr><tr><td><code>STORAGE</code> </td><td>no </td></tr><tr><td><code>SUPERUSER</code> </td><td>no </td></tr><tr><td><code>TABLE</code> </td><td>yes </td></tr><tr><td><code>TEXT</code> </td><td>no </td></tr><tr><td><code>TIMESTAMP</code> </td><td>no </td></tr><tr><td><code>TIMEUUID</code> </td><td>no </td></tr><tr><td><code>THREE</code> </td><td>yes </td></tr><tr><td><code>TOKEN</code> </td><td>yes </td></tr><tr><td><code>TRUNCATE</code> </td><td>yes </td></tr><tr><td><code>TTL</code> </td><td>no </td></tr><tr><td><code>TWO</code> </td><td>yes </td></tr><tr><td><code>TYPE</code> </td><td>no </td></tr><tr><td><code>UPDATE</code> </td><td>yes
</td></tr><tr><td><code>USE</code> </td><td>yes </td></tr><tr><td><code>USER</code> </td><td>no </td></tr><tr><td><code>USERS</code> </td><td>no </td></tr><tr><td><code>USING</code> </td><td>yes </td></tr><tr><td><code>UUID</code> </td><td>no </td></tr><tr><td><code>VALUES</code> </td><td>no </td></tr><tr><td><code>VARCHAR</code> </td><td>no </td></tr><tr><td><code>VARINT</code> </td><td>no </td></tr><tr><td><code>WHERE</code> </td><td>yes </td></tr><tr><td><code>WITH</code> </td><td>yes </td></tr><tr><td><code>WRITETIME</code> </td><td>no </td></tr></table><h2 id="changes">Changes</h2><p>The following describes the addition/changes brought for each version of CQL.</p><h3 id="a3.1.0">3.1.0</h3><ul><li><a href="#alterTableStmt">ALTER TABLE</a> <code>DROP</code> option has been reenabled for CQL3 tables and has new semantics now: the space formerly used by dropped columns will now be eventually reclaimed
(post-compaction). You should not readd previously dropped columns unless you use timestamps with microsecond precision (see <a href="https://issues.apache.org/jira/browse/CASSANDRA-3919">CASSANDRA-3919</a> for more details).</li><li><code>SELECT</code> statement now supports aliases in select clause. Aliases in WHERE and ORDER BY clauses are not supported. See the “section on select”#selectStmt for details.</li><li><code>CREATE</code> statements for <code>KEYSPACE</code>, <code>TABLE</code> and <code>INDEX</code> now supports an <code>IF NOT EXISTS</code> condition. Similarly, <code>DROP</code> statements support a <code>IF EXISTS</code> condition.</li><li><code>INSERT</code> statements optionally supports a <code>IF NOT EXISTS</code> condition and <code>UDPATE</code> supports <code>IF</code> conditions.</li></ul><h3 id="a3.0.5">3.0.5</h3><ul><li><code>SELECT</code>, <code>UPDATE</code>, and <code>DELETE</code> statements now allow empty <code>IN</code> relations (see
<a href="https://issues.apache.org/jira/browse/CASSANDRA-5626">CASSANDRA-5626</a>).</li></ul><h3 id="a3.0.4">3.0.4</h3><ul><li>Updated the syntax for custom <a href="#createIndexStmt">secondary indexes</a>.</li><li>Non-equal condition on the partition key are now never supported, even for ordering partitioner as this was not correct (the order was <strong>not</strong> the one of the type of the partition key). Instead, the <code>token</code> method should always be used for range queries on the partition key (see <a href="#selectWhere">WHERE clauses</a>).</li></ul><h3 id="a3.0.3">3.0.3</h3><ul><li>Support for custom <a href="#createIndexStmt">secondary indexes</a> has been added.</li></ul><h3 id="a3.0.2">3.0.2</h3><ul><li>Type validation for the <a href="#constants">constants</a> has been fixed. For instance, the implementation used to allow <code>'2'</code> as a valid value for an <code>int</code> column (interpreting it has the equivalent of <code>2</code>), or <code>42</code> as
a valid <code>blob</code> value (in which case <code>42</code> was interpreted as an hexadecimal representation of the blob). This is no longer the case, type validation of constants is now more strict. See the <a href="#types">data types</a> section for details on which constant is allowed for which type.</li><li>The type validation fixed of the previous point has lead to the introduction of <a href="#constants">blobs constants</a> to allow inputing blobs. Do note that while inputing blobs as strings constant is still supported by this version (to allow smoother transition to blob constant), it is now deprecated (in particular the <a href="#types">data types</a> section does not list strings constants as valid blobs) and will be removed by a future version. If you were using strings as blobs, you should thus update your client code asap to switch blob constants.</li><li>A number of functions to convert native types to blobs have also been introduced. Furthermore the token function
is now also allowed in select clauses. See the <a href="#functions">section on functions</a> for details.</li></ul><h3 id="a3.0.1">3.0.1</h3><ul><li><a href="#usingdates">Date strings</a> (and timestamps) are no longer accepted as valid <code>timeuuid</code> values. Doing so was a bug in the sense that date string are not valid <code>timeuuid</code>, and it was thus resulting in <a href="https://issues.apache.org/jira/browse/CASSANDRA-4936">confusing behaviors</a>. However, the following new methods have been added to help working with <code>timeuuid</code>: <code>now</code>, <code>minTimeuuid</code>, <code>maxTimeuuid</code> , <code>dateOf</code> and <code>unixTimestampOf</code>. See the <a href="#usingtimeuuid">section dedicated to these methods</a> for more detail.</li><li>“Float constants”#constants now support the exponent notation. In other words, <code>4.2E10</code> is now a valid floating point value.</li></ul><h2 id="Versioning">Versioning</h2><p>Versioning of
the CQL language adheres to the <a href="http://semver.org">Semantic Versioning</a> guidelines. Versions take the form X.Y.Z where X, Y, and Z are integer values representing major, minor, and patch level respectively. There is no correlation between Cassandra release versions and the CQL language version.</p><table><tr><th>version</th><th>description</th></tr><tr><td>Major </td><td>The major version <em>must</em> be bumped when backward incompatible changes are introduced. This should rarely occur.</td></tr><tr><td>Minor </td><td>Minor version increments occur when new, but backward compatible, functionality is introduced.</td></tr><tr><td>Patch </td><td>The patch version is incremented when bugs are fixed.</td></tr></table></body></html>
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+</pre></pre> <p>will select all rows where the <code>timeuuid</code> column <code>t</code> is strictly older than ‘2013-01-01 00:05+0000’ but stricly younger than ‘2013-02-02 10:00+0000’. Please note that <code>t >= maxTimeuuid('2013-01-01 00:05+0000')</code> would still <em>not</em> select a <code>timeuuid</code> generated exactly at ‘2013-01-01 00:05+0000’ and is essentially equivalent to <code>t > maxTimeuuid('2013-01-01 00:05+0000')</code>.</p><p><em>Warning</em>: We called the values generated by <code>minTimeuuid</code> and <code>maxTimeuuid</code> <em>fake</em> UUID because they do no respect the Time-Based UUID generation process specified by the <a href="http://www.ietf.org/rfc/rfc4122.txt">RFC 4122</a>. In particular, the value returned by these 2 methods will not be unique. This means you should only use those methods for querying (as in the example above). Inserting the result of those methods is almost certainly <em>a bad idea</em>.<
/p><h4 id="dateOfandunixTimestampOf"><code>dateOf</code> and <code>unixTimestampOf</code></h4><p>The <code>dateOf</code> and <code>unixTimestampOf</code> functions take a <code>timeuuid</code> argument and extract the embeded timestamp. However, while the <code>dateof</code> function return it with the <code>timestamp</code> type (that most client, including cqlsh, interpret as a date), the <code>unixTimestampOf</code> function returns it as a <code>bigint</code> raw value.</p><h3 id="blobFun">Blob conversion functions</h3><p>A number of functions are provided to “convert” the native types into binary data (<code>blob</code>). For every <code><native-type></code> <code>type</code> supported by CQL3 (a notable exceptions is <code>blob</code>, for obvious reasons), the function <code>typeAsBlob</code> takes a argument of type <code>type</code> and return it as a <code>blob</code>. Conversely, the function <code>blobAsType</code> takes a 64-bit <code>blob</code> argumen
t and convert it to a <code>bigint</code> value. And so for instance, <code>bigintAsBlob(3)</code> is <code>0x0000000000000003</code> and <code>blobAsBigint(0x0000000000000003)</code> is <code>3</code>.</p><h2 id="appendixA">Appendix A: CQL Keywords</h2><p>CQL distinguishes between <em>reserved</em> and <em>non-reserved</em> keywords. Reserved keywords cannot be used as identifier, they are truly reserved for the language (but one can enclose a reserved keyword by double-quotes to use it as an identifier). Non-reserved keywords however only have a specific meaning in certain context but can used as identifer otherwise. The only <em>raison d'être</em> of these non-reserved keywords is convenience: some keyword are non-reserved when it was always easy for the parser to decide whether they were used as keywords or not.</p><table><tr><th>Keyword </th><th>Reserved? </th></tr><tr><td><code>ADD</code> </td><td>yes </td></tr><tr><td><code>ALL</code> </td><td>no <
/td></tr><tr><td><code>ALTER</code> </td><td>yes </td></tr><tr><td><code>AND</code> </td><td>yes </td></tr><tr><td><code>ANY</code> </td><td>yes </td></tr><tr><td><code>APPLY</code> </td><td>yes </td></tr><tr><td><code>AS</code> </td><td>no </td></tr><tr><td><code>ASC</code> </td><td>yes </td></tr><tr><td><code>ASCII</code> </td><td>no </td></tr><tr><td><code>AUTHORIZE</code> </td><td>yes </td></tr><tr><td><code>BATCH</code> </td><td>yes </td></tr><tr><td><code>BEGIN</code> </td><td>yes </td></tr><tr><td><code>BIGINT</code> </td><td>no </td></tr><tr><td><code>BLOB</code> </td><td>no </td></tr><tr><td><code>BOOLEAN</code> </td><td>no </td></tr><tr><td><code>BY</code> </td><td>yes </td></tr><tr><td><code>CLUSTERING</code> </td><td>no </td></tr><tr><td><code>COLUMNFAMILY</code> </td><td>yes </td></tr><tr><td><code>COMPACT</code> </td><td>no </td></tr><tr><td><code>CONSI
STENCY</code> </td><td>no </td></tr><tr><td><code>COUNT</code> </td><td>no </td></tr><tr><td><code>COUNTER</code> </td><td>no </td></tr><tr><td><code>CREATE</code> </td><td>yes </td></tr><tr><td><code>DECIMAL</code> </td><td>no </td></tr><tr><td><code>DELETE</code> </td><td>yes </td></tr><tr><td><code>DESC</code> </td><td>yes </td></tr><tr><td><code>DOUBLE</code> </td><td>no </td></tr><tr><td><code>DROP</code> </td><td>yes </td></tr><tr><td><code>EACH_QUORUM</code> </td><td>yes </td></tr><tr><td><code>FLOAT</code> </td><td>no </td></tr><tr><td><code>FROM</code> </td><td>yes </td></tr><tr><td><code>GRANT</code> </td><td>yes </td></tr><tr><td><code>IN</code> </td><td>yes </td></tr><tr><td><code>INDEX</code> </td><td>yes </td></tr><tr><td><code>CUSTOM</code> </td><td>no </td></tr><tr><td><code>INSERT</code> </td><td>yes </td></tr><tr><td><code>INT</code> </td><td>no
</td></tr><tr><td><code>INTO</code> </td><td>yes </td></tr><tr><td><code>KEY</code> </td><td>no </td></tr><tr><td><code>KEYSPACE</code> </td><td>yes </td></tr><tr><td><code>LEVEL</code> </td><td>no </td></tr><tr><td><code>LIMIT</code> </td><td>yes </td></tr><tr><td><code>LOCAL_QUORUM</code> </td><td>yes </td></tr><tr><td><code>MODIFY</code> </td><td>yes </td></tr><tr><td><code>NORECURSIVE</code> </td><td>yes </td></tr><tr><td><code>NOSUPERUSER</code> </td><td>no </td></tr><tr><td><code>OF</code> </td><td>yes </td></tr><tr><td><code>ON</code> </td><td>yes </td></tr><tr><td><code>ONE</code> </td><td>yes </td></tr><tr><td><code>ORDER</code> </td><td>yes </td></tr><tr><td><code>PASSWORD</code> </td><td>no </td></tr><tr><td><code>PERMISSION</code> </td><td>no </td></tr><tr><td><code>PERMISSIONS</code> </td><td>no </td></tr><tr><td><code>PRIMARY</code> </td><td>yes </td></tr><tr><td><code>QUOR
UM</code> </td><td>yes </td></tr><tr><td><code>REVOKE</code> </td><td>yes </td></tr><tr><td><code>SCHEMA</code> </td><td>yes </td></tr><tr><td><code>SELECT</code> </td><td>yes </td></tr><tr><td><code>SET</code> </td><td>yes </td></tr><tr><td><code>STORAGE</code> </td><td>no </td></tr><tr><td><code>SUPERUSER</code> </td><td>no </td></tr><tr><td><code>TABLE</code> </td><td>yes </td></tr><tr><td><code>TEXT</code> </td><td>no </td></tr><tr><td><code>TIMESTAMP</code> </td><td>no </td></tr><tr><td><code>TIMEUUID</code> </td><td>no </td></tr><tr><td><code>THREE</code> </td><td>yes </td></tr><tr><td><code>TOKEN</code> </td><td>yes </td></tr><tr><td><code>TRUNCATE</code> </td><td>yes </td></tr><tr><td><code>TTL</code> </td><td>no </td></tr><tr><td><code>TWO</code> </td><td>yes </td></tr><tr><td><code>TYPE</code> </td><td>no </td></tr><tr><td><code>UPDATE</code> </td><td>yes
</td></tr><tr><td><code>USE</code> </td><td>yes </td></tr><tr><td><code>USER</code> </td><td>no </td></tr><tr><td><code>USERS</code> </td><td>no </td></tr><tr><td><code>USING</code> </td><td>yes </td></tr><tr><td><code>UUID</code> </td><td>no </td></tr><tr><td><code>VALUES</code> </td><td>no </td></tr><tr><td><code>VARCHAR</code> </td><td>no </td></tr><tr><td><code>VARINT</code> </td><td>no </td></tr><tr><td><code>WHERE</code> </td><td>yes </td></tr><tr><td><code>WITH</code> </td><td>yes </td></tr><tr><td><code>WRITETIME</code> </td><td>no </td></tr><tr><td><code>DISTINCT</code> </td><td>no </td></tr></table><h2 id="changes">Changes</h2><p>The following describes the addition/changes brought for each version of CQL.</p><h3 id="a3.1.1">3.1.1</h3><ul><li><code>SELECT</code> statement now allows listing the partition keys (using the <code>DISTINCT</code> modifier). See <a href="https://issues.apache.
org/jira/browse/CASSANDRA-4536">CASSANDRA-4536</a>.</li></ul><h3 id="a3.1.0">3.1.0</h3><ul><li><a href="#alterTableStmt">ALTER TABLE</a> <code>DROP</code> option has been reenabled for CQL3 tables and has new semantics now: the space formerly used by dropped columns will now be eventually reclaimed (post-compaction). You should not readd previously dropped columns unless you use timestamps with microsecond precision (see <a href="https://issues.apache.org/jira/browse/CASSANDRA-3919">CASSANDRA-3919</a> for more details).</li><li><code>SELECT</code> statement now supports aliases in select clause. Aliases in WHERE and ORDER BY clauses are not supported. See the “section on select”#selectStmt for details.</li><li><code>CREATE</code> statements for <code>KEYSPACE</code>, <code>TABLE</code> and <code>INDEX</code> now supports an <code>IF NOT EXISTS</code> condition. Similarly, <code>DROP</code> statements support a <code>IF EXISTS</code> condition.</li><li><code>INSERT</code>
statements optionally supports a <code>IF NOT EXISTS</code> condition and <code>UDPATE</code> supports <code>IF</code> conditions.</li></ul><h3 id="a3.0.5">3.0.5</h3><ul><li><code>SELECT</code>, <code>UPDATE</code>, and <code>DELETE</code> statements now allow empty <code>IN</code> relations (see <a href="https://issues.apache.org/jira/browse/CASSANDRA-5626">CASSANDRA-5626</a>).</li></ul><h3 id="a3.0.4">3.0.4</h3><ul><li>Updated the syntax for custom <a href="#createIndexStmt">secondary indexes</a>.</li><li>Non-equal condition on the partition key are now never supported, even for ordering partitioner as this was not correct (the order was <strong>not</strong> the one of the type of the partition key). Instead, the <code>token</code> method should always be used for range queries on the partition key (see <a href="#selectWhere">WHERE clauses</a>).</li></ul><h3 id="a3.0.3">3.0.3</h3><ul><li>Support for custom <a href="#createIndexStmt">secondary indexes</a> has been added.</li></ul>
<h3 id="a3.0.2">3.0.2</h3><ul><li>Type validation for the <a href="#constants">constants</a> has been fixed. For instance, the implementation used to allow <code>'2'</code> as a valid value for an <code>int</code> column (interpreting it has the equivalent of <code>2</code>), or <code>42</code> as a valid <code>blob</code> value (in which case <code>42</code> was interpreted as an hexadecimal representation of the blob). This is no longer the case, type validation of constants is now more strict. See the <a href="#types">data types</a> section for details on which constant is allowed for which type.</li><li>The type validation fixed of the previous point has lead to the introduction of <a href="#constants">blobs constants</a> to allow inputing blobs. Do note that while inputing blobs as strings constant is still supported by this version (to allow smoother transition to blob constant), it is now deprecated (in particular the <a href="#types">data types</a> section does not list stri
ngs constants as valid blobs) and will be removed by a future version. If you were using strings as blobs, you should thus update your client code asap to switch blob constants.</li><li>A number of functions to convert native types to blobs have also been introduced. Furthermore the token function is now also allowed in select clauses. See the <a href="#functions">section on functions</a> for details.</li></ul><h3 id="a3.0.1">3.0.1</h3><ul><li><a href="#usingdates">Date strings</a> (and timestamps) are no longer accepted as valid <code>timeuuid</code> values. Doing so was a bug in the sense that date string are not valid <code>timeuuid</code>, and it was thus resulting in <a href="https://issues.apache.org/jira/browse/CASSANDRA-4936">confusing behaviors</a>. However, the following new methods have been added to help working with <code>timeuuid</code>: <code>now</code>, <code>minTimeuuid</code>, <code>maxTimeuuid</code> , <code>dateOf</code> and <code>unixTimestampOf</code>. See the
<a href="#usingtimeuuid">section dedicated to these methods</a> for more detail.</li><li>“Float constants”#constants now support the exponent notation. In other words, <code>4.2E10</code> is now a valid floating point value.</li></ul><h2 id="Versioning">Versioning</h2><p>Versioning of the CQL language adheres to the <a href="http://semver.org">Semantic Versioning</a> guidelines. Versions take the form X.Y.Z where X, Y, and Z are integer values representing major, minor, and patch level respectively. There is no correlation between Cassandra release versions and the CQL language version.</p><table><tr><th>version</th><th>description</th></tr><tr><td>Major </td><td>The major version <em>must</em> be bumped when backward incompatible changes are introduced. This should rarely occur.</td></tr><tr><td>Minor </td><td>Minor version increments occur when new, but backward compatible, functionality is introduced.</td></tr><tr><td>Patch </td><td>The patch version is i
ncremented when bugs are fixed.</td></tr></table></body></html>
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