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Posted to commits@cassandra.apache.org by ty...@apache.org on 2014/07/22 19:10:09 UTC
svn commit: r1612612 - /cassandra/site/publish/doc/cql/CQL.html
Author: tylerhobbs
Date: Tue Jul 22 17:10:08 2014
New Revision: 1612612
URL: http://svn.apache.org/r1612612
Log:
Add note about CQL2 removal to CQL2 docs
Modified:
cassandra/site/publish/doc/cql/CQL.html
Modified: cassandra/site/publish/doc/cql/CQL.html
URL: http://svn.apache.org/viewvc/cassandra/site/publish/doc/cql/CQL.html?rev=1612612&r1=1612611&r2=1612612&view=diff
==============================================================================
--- cassandra/site/publish/doc/cql/CQL.html (original)
+++ cassandra/site/publish/doc/cql/CQL.html Tue Jul 22 17:10:08 2014
@@ -1,4 +1,4 @@
-<?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><!-- This is only a suggestion, to demonstrate that the pre.syntax and pre.sample classes should probably be rendered differently. Render as you like. --><link rel="StyleSheet" href="CQL.css" type="text/css" media="screen"></p><h1 id="CassandraQueryLanguageCQLv2.0">Cassandra Query Language (CQL) v2.0</h1><h2 id="TableofContents">Table of Contents</h2><ol style="list-style: none;"><li><a href="CQL.html#CassandraQueryLanguageCQLv2.0">Cassandra Query Language (CQL) v2.0</a><ol style="list-style: none;"><li><a href="CQL.html#TableofContents">Table of Contents</a></li><li><a href="CQL.html#Syntaxconventions">Syntax conventions</a></li><li><a href="CQL.html#Overallsyntax">Overall syn
tax</a></li><li><a href="CQL.html#storageTypes">Data Storage Types</a><ol style="list-style: none;"><li><a href="CQL.html#usingdates">Working with dates</a></li></ol></li><li><a href="CQL.html#USE">USE</a></li><li><a href="CQL.html#SELECT">SELECT</a><ol style="list-style: none;"><li><a href="CQL.html#SpecifyingColumns">Specifying Columns</a></li><li><a href="CQL.html#ColumnFamily">Column Family</a></li><li><a href="CQL.html#ConsistencyLevel">Consistency Level</a></li><li><a href="CQL.html#Filteringrows">Filtering rows</a></li><li><a href="CQL.html#Limits">Limits</a></li></ol></li><li><a href="CQL.html#INSERT">INSERT</a></li><li><a href="CQL.html#update">UPDATE</a><ol style="list-style: none;"><li><a href="CQL.html#ColumnFamily2">Column Family</a></li><li><a href="CQL.html#ConsistencyLevel2">Consistency Level</a></li><li><a href="CQL.html#Timestamp">Timestamp</a></li><li><a href="CQL.html#TTL">TTL</a></li><li><a href="CQL.html#SpecifyingColumnsandRow">Specifying Columns and Row</a></
li><li><a href="CQL.html#UpdatingCounterColumns">Updating Counter Columns</a></li></ol></li><li><a href="CQL.html#DELETE">DELETE</a><ol style="list-style: none;"><li><a href="CQL.html#SpecifyingColumns2">Specifying Columns</a></li><li><a href="CQL.html#ColumnFamily3">Column Family</a></li><li><a href="CQL.html#ConsistencyLevel3">Consistency Level</a></li><li><a href="CQL.html#deleterows">Specifying Rows</a></li></ol></li><li><a href="CQL.html#TRUNCATE">TRUNCATE</a></li><li><a href="CQL.html#BATCH">BATCH</a></li><li><a href="CQL.html#CREATEKEYSPACE">CREATE KEYSPACE</a></li><li><a href="CQL.html#CREATECOLUMNFAMILY">CREATE COLUMNFAMILY</a><ol style="list-style: none;"><li><a href="CQL.html#keytypes">Specifying Key Type</a></li><li><a href="CQL.html#SpecifyingColumnTypesoptional">Specifying Column Types (optional)</a></li><li><a href="CQL.html#ColumnFamilyOptionsoptional">Column Family Options (optional)</a></li></ol></li><li><a href="CQL.html#CREATEINDEX">CREATE INDEX</a></li><li><a hr
ef="CQL.html#DROPKEYSPACE">DROP KEYSPACE</a></li><li><a href="CQL.html#DROPCOLUMNFAMILY">DROP COLUMNFAMILY</a></li><li><a href="CQL.html#DROPINDEX">DROP INDEX</a></li><li><a href="CQL.html#ALTERCOLUMNFAMILY">ALTER COLUMNFAMILY</a><ol style="list-style: none;"><li><a href="CQL.html#Changingthetypeofatypedcolumn">Changing the type of a typed column</a></li><li><a href="CQL.html#Addingatypedcolumn">Adding a typed column</a></li><li><a href="CQL.html#Droppingatypedcolumn">Dropping a typed column</a></li></ol></li><li><a href="CQL.html#CommonIdioms">Common Idioms</a><ol style="list-style: none;"><li><a href="CQL.html#consistency">Specifying Consistency</a></li></ol></li></ol></li><li><a href="CQL.html#Versioning">Versioning</a></li><li><a href="CQL.html#Changes">Changes</a></li></ol><h2 id="Syntaxconventions">Syntax conventions</h2><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 <acronym title="B
ackus-Naur Form">BNF</acronym>-like notation, looking like this:</li></ul><pre class="syntax"><pre><Start> ::= <CQL_Statement>*
+<?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><!-- This is only a suggestion, to demonstrate that the pre.syntax and pre.sample classes should probably be rendered differently. Render as you like. --><link rel="StyleSheet" href="CQL.css" type="text/css" media="screen"></p><h1 id="CassandraQueryLanguageCQLv2.0">Cassandra Query Language (CQL) v2.0</h1><p><b><span style="color:red">NOTICE</span></b>: CQL 2 has been deprecated since Cassandra 2.0, and will be removed in Cassandra 3.0. It is recommended that you upgrade to CQL 3, which has much better driver support and many new features. For further reading, see the <a href="http://cassandra.apache.org/doc/cql3/CQL.html">CQL 3 documentation</a> and the <a href="http://wiki.a
pache.org/cassandra/ClientOptions">CQL 3 drivers</a>.</p><h2 id="TableofContents">Table of Contents</h2><ol style="list-style: none;"><li><a href="CQL.html#CassandraQueryLanguageCQLv2.0">Cassandra Query Language (CQL) v2.0</a><ol style="list-style: none;"><li><a href="CQL.html#TableofContents">Table of Contents</a></li><li><a href="CQL.html#Syntaxconventions">Syntax conventions</a></li><li><a href="CQL.html#Overallsyntax">Overall syntax</a></li><li><a href="CQL.html#storageTypes">Data Storage Types</a><ol style="list-style: none;"><li><a href="CQL.html#usingdates">Working with dates</a></li></ol></li><li><a href="CQL.html#USE">USE</a></li><li><a href="CQL.html#SELECT">SELECT</a><ol style="list-style: none;"><li><a href="CQL.html#SpecifyingColumns">Specifying Columns</a></li><li><a href="CQL.html#ColumnFamily">Column Family</a></li><li><a href="CQL.html#ConsistencyLevel">Consistency Level</a></li><li><a href="CQL.html#Filteringrows">Filtering rows</a></li><li><a href="CQL.html#Limits
">Limits</a></li></ol></li><li><a href="CQL.html#INSERT">INSERT</a></li><li><a href="CQL.html#update">UPDATE</a><ol style="list-style: none;"><li><a href="CQL.html#ColumnFamily2">Column Family</a></li><li><a href="CQL.html#ConsistencyLevel2">Consistency Level</a></li><li><a href="CQL.html#Timestamp">Timestamp</a></li><li><a href="CQL.html#TTL">TTL</a></li><li><a href="CQL.html#SpecifyingColumnsandRow">Specifying Columns and Row</a></li><li><a href="CQL.html#UpdatingCounterColumns">Updating Counter Columns</a></li></ol></li><li><a href="CQL.html#DELETE">DELETE</a><ol style="list-style: none;"><li><a href="CQL.html#SpecifyingColumns2">Specifying Columns</a></li><li><a href="CQL.html#ColumnFamily3">Column Family</a></li><li><a href="CQL.html#ConsistencyLevel3">Consistency Level</a></li><li><a href="CQL.html#deleterows">Specifying Rows</a></li></ol></li><li><a href="CQL.html#TRUNCATE">TRUNCATE</a></li><li><a href="CQL.html#BATCH">BATCH</a></li><li><a href="CQL.html#CREATEKEYSPACE">CREAT
E KEYSPACE</a></li><li><a href="CQL.html#CREATECOLUMNFAMILY">CREATE COLUMNFAMILY</a><ol style="list-style: none;"><li><a href="CQL.html#keytypes">Specifying Key Type</a></li><li><a href="CQL.html#SpecifyingColumnTypesoptional">Specifying Column Types (optional)</a></li><li><a href="CQL.html#cfopts">Column Family Options (optional)</a></li></ol></li><li><a href="CQL.html#CREATEINDEX">CREATE INDEX</a></li><li><a href="CQL.html#DROPKEYSPACE">DROP KEYSPACE</a></li><li><a href="CQL.html#DROPCOLUMNFAMILY">DROP COLUMNFAMILY</a></li><li><a href="CQL.html#DROPINDEX">DROP INDEX</a></li><li><a href="CQL.html#ALTERCOLUMNFAMILY">ALTER COLUMNFAMILY</a><ol style="list-style: none;"><li><a href="CQL.html#Changingthetypeofatypedcolumn">Changing the type of a typed column</a></li><li><a href="CQL.html#Addingatypedcolumn">Adding a typed column</a></li><li><a href="CQL.html#Droppingatypedcolumn">Dropping a typed column</a></li><li><a href="CQL.html#Modifyingcolumnfamilyproperties">Modifying column fami
ly properties</a></li></ol></li><li><a href="CQL.html#CommonIdioms">Common Idioms</a><ol style="list-style: none;"><li><a href="CQL.html#consistency">Specifying Consistency</a></li></ol></li></ol></li><li><a href="CQL.html#Versioning">Versioning</a></li><li><a href="CQL.html#Changes">Changes</a></li></ol><h2 id="Syntaxconventions">Syntax conventions</h2><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 <acronym title="Backus-Naur Form">BNF</acronym>-like notation, looking like this:</li></ul><pre class="syntax"><pre><Start> ::= <CQL_Statement>*
;
</pre></pre><ul><li>Nonterminal symbols in syntax rules will have <code><angle brackets></code>.</li><li>Terminal symbols will be shown in <code>"single quotes"</code>.</li><li>As an additional shortcut notation to BNF, optional symbols (that can occur zero or one times) will be followed by a <code>?</code> marker. Optional symbols that can occur zero or any number of times will be followed by a <code>*</code> marker. Multiple symbols may be grouped together in <code>(parentheses)</code> to signify that they are all optional or repeatable together.</li><li>In a few cases where meaning is more easily conveyed through prose, we explain a symbol and its expansion without BNF.</li><li>Sample code will also be shown 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><h2 id="Overallsyntax">Overall syntax</h2><p>CQL consists of statements. As in SQL, some statements directly make changes to data, some look up data, and some change the way data is stored.</p><p>All statements end with a semicolon.</p><pre class="syntax"><pre><CQL_Statement> ::= <statementBody> ";"
@@ -175,16 +175,14 @@ CREATE KEYSPACE Excalibur WITH strategy_
</pre></pre><p>The <code>CREATE KEYSPACE</code> statement creates a new top-level namespace (aka “keyspace”). Valid names are any string constructed of alphanumeric characters and underscores. Names which do not work as valid identifiers or integers should be quoted as string literals. Properties such as replication strategy and count are specified during creation using the following accepted keyword arguments:</p><table><tr><th>keyword</th><th>required</th><th>description</th></tr><tr><td>strategy_class</td><td>yes</td><td>The name of the replication strategy class which should be used for the new keyspace. Some often-used classes are <code>SimpleStrategy</code> and <code>NetworkTopologyStrategy</code>.</td></tr><tr><td>strategy_options</td><td>no</td><td>Most strategies require additional arguments which can be supplied by appending the option name to the <code>strategy_options</code> keyword, separated by a colon (<code>:</code>). For example, a strategy option of &#
8220;DC1” with a value of “1” would be specified as <code>strategy_options:DC1 = 1</code>; replication_factor for SimpleStrategy could be <code>strategy_options:replication_factor=3</code>.</td></tr></table><h2 id="CREATECOLUMNFAMILY">CREATE COLUMNFAMILY</h2><p><i>Syntax:</i></p><pre class="syntax"><pre><createColumnFamilyStatement> ::= "CREATE" "COLUMNFAMILY" <name>
"(" <term> <storageType> "PRIMARY" "KEY"
( "," <term> <storageType> )* ")"
- ( "WITH" <identifier> "=" <cfOptionVal>
- ( "AND" <identifier> "=" <cfOptionVal> )* )?
+ ( "WITH" <optionName> "=" <cfOptionVal>
+ ( "AND" <optionName> "=" <cfOptionVal> )* )?
;
-<cfOptionVal> ::= <storageType>
- | <identifier>
- | <stringLiteral>
- | <integer>
- | <float>
- ;
-</pre></pre><p><i>Sample:</i></p><pre class="sample"><pre>CREATE COLUMNFAMILY Fish (KEY blob PRIMARY KEY);
+<optionName> ::= <identifier>
+ | <optionName> ":" <identifier>
+ | <optionName> ":" <integer>
+ ;
+</pre></pre><p><cfOptionVal> ::= <storageType><br/> | <identifier><br/> | <stringLiteral><br/> | <integer><br/> | <float><br/> ;</p><p><i>Sample:</i></p><pre class="sample"><pre>CREATE COLUMNFAMILY Fish (KEY blob PRIMARY KEY);
CREATE COLUMNFAMILY FastFoodEatings (user text PRIMARY KEY)
WITH comparator=timestamp AND default_validation=int;
CREATE COLUMNFAMILY MonkeyTypes (
@@ -196,8 +194,8 @@ CREATE COLUMNFAMILY MonkeyTypes (
AND read_repair_chance = 1.0;
</pre></pre><p><code>CREATE COLUMNFAMILY</code> statements create new column family namespaces under the current keyspace. Valid column family names are strings of alphanumeric characters and underscores, which begin with a letter.</p><h3 id="keytypes">Specifying Key Type</h3><pre class="sample"><pre>CREATE ... (KEY ascii PRIMARY KEY, ... ) ...
</pre></pre><p>When creating a new column family, you must specify the key type. The list of possible types is identical to column comparators/validators (see <a href="#storageTypes">Data Storage Types</a>), except it probably does not make sense to use <code>counter</code> for a key. It’s important to note that the key type you use must be compatible with the partitioner in use. For example, <code>OrderPreservingPartitioner</code> and <code>CollatingOrderPreservingPartitioner</code> both require UTF-8 keys. If you use an identifier for the primary key name, instead of the <code>KEY</code> keyword, a key alias will be set automatically.</p><h3 id="SpecifyingColumnTypesoptional">Specifying Column Types (optional)</h3><pre class="sample"><pre>CREATE ... ( ... , name1 type1, name2 type2, ... ) ...
-</pre></pre><p>It is possible to assign columns a type during column family creation. Columns configured with a type are validated accordingly when a write occurs, and intelligent CQL drivers and interfaces will be able to decode the column values correctly when receiving them. Column types are specified as a parenthesized, comma-separated list of column term and type pairs. See <a href="#storageTypes">Data Storage Types</a> for the list of recognized types.</p><h3 id="ColumnFamilyOptionsoptional">Column Family Options (optional)</h3><pre class="sample"><pre>CREATE COLUMNFAMILY ... WITH keyword1 = arg1 AND keyword2 = arg2;
-</pre></pre><p>A number of optional keyword arguments can be supplied to control the configuration of a new column family.</p><table><tr><th>keyword</th><th>default</th><th>description</th></tr><tr><td>comparator</td><td>text</td><td>Determines the storage type of column names (which itself determines the sorting and validation of column names). Valid values are listed in the <a href="#storageTypes">Data Storage Types</a> table above.</td></tr><tr><td>comment</td><td>none</td><td>A free-form, human-readable comment.</td></tr><tr><td>row_cache_provider</td><td>SerializingCacheProvider if JNA is present, otherwise ConcurrentHashMapCacheProvider</td><td>A factory for the cache with which to back the row cache.</td></tr><tr><td>row_cache_size</td><td>0</td><td>Number of rows whose entire contents to cache in memory.</td></tr><tr><td>key_cache_size</td><td>200000</td><td>Number of keys per SSTable whose locations are kept in memory in “mostly LRU” order.</td></tr><tr><td>read
_repair_chance</td><td>1.0</td><td>The probability with which read repairs should be invoked on non-quorum reads.</td></tr><tr><td>gc_grace_seconds</td><td>864000</td><td>Time to wait before garbage collecting tombstones (deletion markers).</td></tr><tr><td>default_validation</td><td>text</td><td>Determines the default storage type of column values (which itself determines the validation for column values). This option does not affect the types of columns which were defined in a <code>CREATE COLUMNFAMILY</code> statement— only new columns. Valid values are listed in the <a href="#storageTypes">Data Storage Types</a> table above.</td></tr><tr><td>min_compaction_threshold</td><td>4</td><td>Minimum number of SSTables needed to start a minor compaction.</td></tr><tr><td>max_compaction_threshold</td><td>32</td><td>Maximum number of SSTables allowed before a minor compaction is forced.</td></tr><tr><td>row_cache_save_period_in_seconds</td><td>0</td><td>Number of seconds between savi
ng row caches.</td></tr><tr><td>key_cache_save_period_in_seconds</td><td>14400</td><td>Number of seconds between saving key caches.</td></tr><tr><td>replicate_on_write</td><td>false</td><td></td></tr></table><h2 id="CREATEINDEX">CREATE INDEX</h2><p><i>Syntax:</i></p><pre class="syntax"><pre><createIndexStatement> ::= "CREATE" "INDEX" <identifier>? "ON"
+</pre></pre><p>It is possible to assign columns a type during column family creation. Columns configured with a type are validated accordingly when a write occurs, and intelligent CQL drivers and interfaces will be able to decode the column values correctly when receiving them. Column types are specified as a parenthesized, comma-separated list of column term and type pairs. See <a href="#storageTypes">Data Storage Types</a> for the list of recognized types.</p><h3 id="cfopts">Column Family Options (optional)</h3><pre class="sample"><pre>CREATE COLUMNFAMILY ... WITH keyword1 = arg1 AND keyword2 = arg2;
+</pre></pre><p>A number of optional keyword arguments can be supplied to control the configuration of a new column family.</p><table><tr><th>keyword</th><th>default</th><th>description</th></tr><tr><td>comparator</td><td>text</td><td>Determines the storage type of column names (which itself determines the sorting and validation of column names). Valid values are listed in the <a href="#storageTypes">Data Storage Types</a> table above.</td></tr><tr><td>comment</td><td>none</td><td>A free-form, human-readable comment.</td></tr><tr><td>read_repair_chance</td><td>1.0</td><td>The probability with which read repairs should be invoked on non-quorum reads.</td></tr><tr><td>gc_grace_seconds</td><td>864000</td><td>Time to wait before garbage collecting tombstones (deletion markers).</td></tr><tr><td>default_validation</td><td>text</td><td>Determines the default storage type of column values (which itself determines the validation for column values). This option does not affect the types of co
lumns which were defined in a <code>CREATE COLUMNFAMILY</code> statement— only new columns. Valid values are listed in the <a href="#storageTypes">Data Storage Types</a> table above.</td></tr><tr><td>min_compaction_threshold</td><td>4</td><td>Minimum number of SSTables needed to start a minor compaction.</td></tr><tr><td>max_compaction_threshold</td><td>32</td><td>Maximum number of SSTables allowed before a minor compaction is forced.</td></tr><tr><td>replicate_on_write</td><td>false</td><td></td></tr><tr><td>compaction_strategy_options</td><td>none</td><td>CompactionStrategy specific options such as “sstable_size_in_mb” for LeveledCompactionStrategy and “min_sstable_size” for SizeTieredCompactionStrategy</td></tr><tr><td>compression_parameters</td><td>none</td><td>Compression parameters such as “sstable_compressor” and "chunk_length_kb"</td></tr></table><h2 id="CREATEINDEX">CREATE INDEX</h2><p><i>Syntax:</i></p><pre class="syntax"><pre><
createIndexStatement> ::= "CREATE" "INDEX" <identifier>? "ON"
<name> "(" <term> ")"
;
</pre></pre><p><i>Sample:</i></p><pre class="sample"><pre>CREATE INDEX userIndex ON NerdMovies (user);
@@ -216,11 +214,14 @@ CREATE INDEX ON Mutants (abilityId);
<alterInstructions> ::= "ALTER" <name> "TYPE" <storageType>
| "ADD" <name> <storageType>
| "DROP" <name>
+ | "WITH" <optionName> "=" <cfOptionVal>
+ ( "AND" <optionName> "=" <cfOptionVal> )*
;
-</pre></pre><p>An <code>ALTER</code> statement is used to manipulate column family column metadata. It allows you to add new columns, drop existing columns, or change the data storage type of existing columns. No results are returned.</p><p>Specify the name of the column family to be changed after the <code>ALTER COLUMNFAMILY</code> keywords, and the name of the column to be changed, added, or dropped after the keyword corresponding to the type of change desired (<code>ALTER</code>, <code>ADD</code>, <code>DROP</code>).</p><h3 id="Changingthetypeofatypedcolumn">Changing the type of a typed column</h3><pre class="sample"><pre>ALTER COLUMNFAMILY addamsFamily ALTER lastKnownLocation TYPE uuid;
-</pre></pre><p><code>ALTER COLUMNFAMILY ... ALTER</code> changes the expected storage type for a column. The column must already have a type in the column family metadata. The column may or may not already exist in current rows— but be aware that no validation of existing data is done. The bytes stored in values for that column will remain unchanged, and if existing data is not deserializable according to the new type, this may cause your CQL driver or interface to report errors.</p><h3 id="Addingatypedcolumn">Adding a typed column</h3><pre class="sample"><pre>ALTER COLUMNFAMILY addamsFamily ADD gravesite varchar;
+</pre></pre><p>An <code>ALTER</code> statement is used to manipulate column family column metadata. It allows you to add new columns, drop existing columns, data storage type of existing columns, or change the column family properties. No results are returned.</p><p>Specify the name of the column family to be changed after the <code>ALTER COLUMNFAMILY</code> keywords, followed by the type of change desired (<code>ALTER</code>, <code>ADD</code>, <code>DROP</code>, or <code>WITH</code>), and provide the rest of the needed information, as explained below.</p><h3 id="Changingthetypeofatypedcolumn">Changing the type of a typed column</h3><pre class="sample"><pre>ALTER COLUMNFAMILY addamsFamily ALTER lastKnownLocation TYPE uuid;
+</pre></pre><p><code>ALTER COLUMNFAMILY ... ALTER</code> changes the expected storage type for a column. The column must either be the key alias or already have a type in the column family metadata. The column may or may not already exist in current rows— but be aware that no validation of existing data is done. The bytes stored in values for that column will remain unchanged, and if existing data is not deserializable according to the new type, this may cause your CQL driver or interface to report errors.</p><h3 id="Addingatypedcolumn">Adding a typed column</h3><pre class="sample"><pre>ALTER COLUMNFAMILY addamsFamily ADD gravesite varchar;
</pre></pre><p>The <code>ALTER COLUMNFAMILY ... ADD</code> variant adds a typed column to a column family. The column must not already have a type in the column family metadata. The same warnings from the above <code>ALTER</code> section, about there being no validation of existing data, apply here as well.</p><h3 id="Droppingatypedcolumn">Dropping a typed column</h3><pre class="sample"><pre>ALTER COLUMNFAMILY addamsFamily DROP gender;
-</pre></pre><p>An <code>ALTER COLUMNFAMILY ... DROP</code> statement removes the type of a column from the column family metadata. Note that this does <em>not</em> remove the column from current rows; it just removes the metadata saying that the bytes stored under that column are expected to be deserializable according to a certain type.</p><h2 id="CommonIdioms">Common Idioms</h2><h3 id="consistency">Specifying Consistency</h3><pre class="syntax"><pre><consistency> ::= "ANY"
+</pre></pre><p>An <code>ALTER COLUMNFAMILY ... DROP</code> statement removes the type of a column from the column family metadata. Note that this does <em>not</em> remove the column from current rows; it just removes the metadata saying that the bytes stored under that column are expected to be deserializable according to a certain type.</p><h3 id="Modifyingcolumnfamilyproperties">Modifying column family properties</h3><pre class="sample"><pre>ALTER COLUMNFAMILY addamsFamily WITH comment = 'A most excellent and useful column family' AND read_repair_chance = 0.2;
+</pre></pre><p>An <code>ALTER COLUMNFAMILY ... WITH</code> statement makes adjustments to the column family properties, as defined when the column family was created (see <a href="#cfopts">CREATE COLUMNFAMILY options</a> for information about the supported options and values).</p><p>Note that setting any <code>compaction_strategy_options:*</code> parameters has the effect of erasing all previous <code>compaction_strategy_options:*</code> parameters, so you will need to re-specify any such parameters which have already been set, if you want to keep them. The same note applies to the set of <code>compression_parameters:*</code> parameters.</p><h2 id="CommonIdioms">Common Idioms</h2><h3 id="consistency">Specifying Consistency</h3><pre class="syntax"><pre><consistency> ::= "ANY"
| "ONE"
| "QUORUM"
| "ALL"