[jira] [Commented] (CALCITE-494) Support NEXT/CURRENT VALUE FOR syntax for sequences usage

["Julian Hyde (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14233610#comment-14233610 ] 

Julian Hyde commented on CALCITE-494:
-------------------------------------

The syntax is quite straightforward.

Calcite already has a NEXT_VALUE operator in SqlStdOperatorTable (not used). We would add a CURRENT_VALUE operator.

Generating code to implementing sequences is a matter of providing implementors for those functions, in whichever language we are targeting. [~jamestaylor], would we need an extra (hidden) parameter to the function so that the function knows whether it is being called for the 2nd time on the same row or whether it has advanced to a new row?

Need to add definitions of sequences to the Schema SPI. 

Expose them a JDBC metadata (they are apparently a table-type), per http://stackoverflow.com/questions/5637423/how-to-retrieve-sequences-metadata-from-jdbc:

{code}
meta.getTables(connection.getCatalog(), null, "%_FOO", new String[] { "SEQUENCE" });
{code}

> Support NEXT/CURRENT VALUE FOR syntax for sequences usage
> ---------------------------------------------------------
>
>                 Key: CALCITE-494
>                 URL: https://issues.apache.org/jira/browse/CALCITE-494
>             Project: Calcite
>          Issue Type: Improvement
>            Reporter: James Taylor
>            Assignee: Julian Hyde
>              Labels: phoenix
>
> Support the ANSI standard NEXT VALUE FOR and CURRENT VALUE FOR syntax to access/increment sequence values. See http://phoenix.apache.org/sequences.html and http://phoenix.apache.org/language/index.html#sequence for examples.



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