[jira] Issue Comment Edited: (CASSANDRA-2025) generalized way of expressing hierarchical values

["Rick Shaw (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-2025?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12985002#action_12985002 ] 

Rick Shaw edited comment on CASSANDRA-2025 at 1/21/11 6:43 PM:
---------------------------------------------------------------

Well some "device" has to be introduced to handle depth, and there are not alot of good choices other that this. The "brackety" one is concise and at least you can parse it both visibly and mechanically; the alternate is some "texty" pattern of AND's and WITH's and such and that is much more wordy and would be really hard to craft in the general sense.

So what part of it is "Not Good"? too many special characters? too confusing? JSON uses this general notation right? 


I am assuming the depth in select you speak of would be used for the addition of "
super-columns" and ultimately arbitrary depth "slices"?

      was (Author: ardot):
    Well some "device" has to be introduced to handle depth, and there are not alot of good choices other that this. The "brackety" one is concise and at least you can parse it both visibly and mechanically; the alternate is some "texty" pattern of AND's and WITHS and such and that is much more wordy and would be really hare to craft in the general sense.

So what part of it is "Not Good"? JSON uses this general notation right? 

I am assuming the depth in select you speak of would be used for the addition of "
super-columns" and ultimately arbitrary depth "slices"?
  
> 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}
> Or in the case of composite column names:
> {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}
> 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?
> *Edit: improved final example*
> *Edit: restore final example, create new one (gah).*

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.