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Posted to commits@cassandra.apache.org by "Eric Evans (JIRA)" <ji...@apache.org> on 2011/01/22 00:24:46 UTC
[jira] Updated: (CASSANDRA-2025) generalized way of expressing
hierarchical values
[ https://issues.apache.org/jira/browse/CASSANDRA-2025?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Eric Evans updated CASSANDRA-2025:
----------------------------------
Description:
While hashing out {{CREATE KEYSPACE}}, it became obvious that we needed a syntax for expressing hierarchical values. Properties like {{replication_factor}} can be expressed simply using keyword arguments like ({{replication_factor = 3}}), but {{strategy_options}} is a map of strings.
The solution I took in CASSANDRA-1709 was to dot-delimit "map name" and option key, so for example:
{code:style=SQL}
CREATE KEYSPACE keyspace WITH ... AND strategy_options.DC1 = "1" ...
{code}
This led me to wonder if this was a general enough approach for any future cases that might come up. One example might be compound/composite column names. Dot-delimiting is a bad choice here since it rules out ever introducing a float literal.
One suggestion would be to colon-delimit, so for example:
{code:style=SQL}
CREATE KEYSPACE keyspace WITH ... AND strategy_options:DC1 = "1" ...
{code}
As an aside, this also led me to the conclusion that {{CONSISTENCY.<LEVEL>}} is probably a bad choice for consistency level specification. It mirrors the underlying enum for no good reason and should probably be changed to {{CONSISTENCY <LEVEL>}} (i.e. omitting the separator). For example:
{code:style=SQL}
SELECT columnA:columnB,column1:column2 FROM Standard2 USING CONSISTENCY QUORUM WHERE KEY = key;
UPDATE Standard2 SET columnA:columnB = valueC, column1:column2 = value3 WHERE KEY = key;
{code}
Thoughts?
*Edit: improved final example*
was:
While hashing out {{CREATE KEYSPACE}}, it became obvious that we needed a syntax for expressing hierarchical values. Properties like {{replication_factor}} can be expressed simply using keyword arguments like ({{replication_factor = 3}}), but {{strategy_options}} is a map of strings.
The solution I took in CASSANDRA-1709 was to dot-delimit "map name" and option key, so for example:
{code:style=SQL}
CREATE KEYSPACE keyspace WITH ... AND strategy_options.DC1 = "1" ...
{code}
This led me to wonder if this was a general enough approach for any future cases that might come up. One example might be compound/composite column names. Dot-delimiting is a bad choice here since it rules out ever introducing a float literal.
One suggestion would be to colon-delimit, so for example:
{code:style=SQL}
CREATE KEYSPACE keyspace WITH ... AND strategy_options:DC1 = "1" ...
{code}
As an aside, this also led me to the conclusion that {{CONSISTENCY.<LEVEL>}} is probably a bad choice for consistency level specification. It mirrors the underlying enum for no good reason and should probably be changed to {{CONSISTENCY <LEVEL>}} (i.e. omitting the separator). For example:
{code:style=SQL}
SELECT column FROM Standard2 USING CONSISTENCY QUORUM WHERE KEY = key;
{code}
Thoughts?
> generalized way of expressing hierarchical values
> -------------------------------------------------
>
> Key: CASSANDRA-2025
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2025
> Project: Cassandra
> Issue Type: Sub-task
> Components: API
> Reporter: Eric Evans
> Assignee: Eric Evans
> Priority: Minor
> Fix For: 0.8
>
> Original Estimate: 0h
> Remaining Estimate: 0h
>
> While hashing out {{CREATE KEYSPACE}}, it became obvious that we needed a syntax for expressing hierarchical values. Properties like {{replication_factor}} can be expressed simply using keyword arguments like ({{replication_factor = 3}}), but {{strategy_options}} is a map of strings.
> The solution I took in CASSANDRA-1709 was to dot-delimit "map name" and option key, so for example:
> {code:style=SQL}
> CREATE KEYSPACE keyspace WITH ... AND strategy_options.DC1 = "1" ...
> {code}
> This led me to wonder if this was a general enough approach for any future cases that might come up. One example might be compound/composite column names. Dot-delimiting is a bad choice here since it rules out ever introducing a float literal.
> One suggestion would be to colon-delimit, so for example:
> {code:style=SQL}
> CREATE KEYSPACE keyspace WITH ... AND strategy_options:DC1 = "1" ...
> {code}
> As an aside, this also led me to the conclusion that {{CONSISTENCY.<LEVEL>}} is probably a bad choice for consistency level specification. It mirrors the underlying enum for no good reason and should probably be changed to {{CONSISTENCY <LEVEL>}} (i.e. omitting the separator). For example:
> {code:style=SQL}
> SELECT columnA:columnB,column1:column2 FROM Standard2 USING CONSISTENCY QUORUM WHERE KEY = key;
> UPDATE Standard2 SET columnA:columnB = valueC, column1:column2 = value3 WHERE KEY = key;
> {code}
> Thoughts?
> *Edit: improved final example*
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