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From "Lukas Eder (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-4379) Let´s add comments to Derby
Date Sun, 27 Mar 2011 14:49:05 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4379?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13011803#comment-13011803

Lukas Eder commented on DERBY-4379:

I am missing this feature as well. Many databases support the Oracle-style COMMENT ON syntax
as originally suggested by Rami Ojares. MySQL's syntax seems a bit inconsistent to me, as
the syntax for commenting on tables is quite different from the one for commenting on columns.
That's not the case with

COMMENT ON [object] IS [comment].

Since the "reserved word" COMMENT is at the beginning of a new command, I don't see how that
would interfere with the current Derby syntax definition. It should be possible to introduce
that keyword without causing trouble to commands like:


> Let´s add comments to Derby
> ---------------------------
>                 Key: DERBY-4379
>                 URL: https://issues.apache.org/jira/browse/DERBY-4379
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions:
>         Environment: N/A
>            Reporter: Rami Ojares
>             Fix For:
> I could not find any previous issue about adding comments to Derby.
> I found one suggestion about it on the web somewhere but not here in Jira.
> DB2 and Oracle seem to have a separate COMMENT ON clause
> Eg.
> COMMENT ON TABLE EMPLOYEE IS 'Reflects first quarter 2000 reorganization'
> COMMENT ON COLUMN mytable.primarykey IS 'Unique ID from Sequence SEQ_MASTER'
> MySql on the other hand has a more compact syntax
> CREATE TABLE FOO (A COMMENT 'This col is A')  COMMENT='And here is the table comment'
> I quess SQL standard does not talk about commenting objects like tables columns etc.
(Although I am not sure, maybe someone could prove me wrong here).
> So I propose we start with syntax like
> CREATE TABLE TBL_NAME (<coldefinition> COMMENT 'colcomment' ...) COMMENT ' tablecomment'
> Column comment could appear anywhere where Column-level-constraint can and the same would
apply for table comment.
> View comment could come after the query in view definition.
> We would only need to add reserved word COMMENT. (Although it is a common word and most
certainly is used by someone as a column or tanle name).
> It might be that there is already a spot for comments (or should we say remarks) because
the DatabaseMetadata returns a column with that name for every attribute.
> It is always empty now.
> This feature could take the self-documenting property of derby databases to the next
> I could code this feature but now I would like to know what people think about this issue
in here and since I have not been coding Derby before then perhaps a few pointers would be
helpful from someone who knows the soucecode of Derby well.

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