[jira] Resolved: (DERBY-1645) ALTER TABLE ... SET INCREMENT BY X... Turns off the "Generated By Default" identity column constraint

["Bryan Pendleton (JIRA)" <ji...@apache.org>]

     [ http://issues.apache.org/jira/browse/DERBY-1645?page=all ]

Bryan Pendleton resolved DERBY-1645.
------------------------------------

    Fix Version/s: 10.3.0.0
       Resolution: Fixed

I've committed the patch attached to DERBY-1495 to subversion
as revision 474502. DERBY-1495 and DERBY-1645 are not
precisely speaking duplicates, but as was noted in the comments above,
a single fix resolves both problems. The patch changes the ALTER TABLE
handling so that the parts of the identify column that you aren't altering
are preserved and not incorrectly reset.

> ALTER TABLE ... SET INCREMENT BY X... Turns off the "Generated By Default" identity column constraint
> -----------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-1645
>                 URL: http://issues.apache.org/jira/browse/DERBY-1645
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 10.1.3.1
>         Environment: Both Ubuntu Linux, Windows XP... Java 1.4.2_x and Java 1.5
>            Reporter: Alan Baldwin
>         Assigned To: Bryan Pendleton
>             Fix For: 10.3.0.0
>
>
> I have a table which has an auto-generated key:
> create table MyTable  (
>    TableId INTEGER GENERATED BY DEFAULT AS IDENTITY NOT NULL,
>    StringValue           VARCHAR(20)           not null,
>    constraint PK_MyTable primary key (TableId)
> )
> I verify that GENERATED BY DEFAULT is set:
> SELECT * FROM 
> sys.syscolumns col 
> INNER JOIN sys.systables tab ON col.referenceId = tab.tableid 
> WHERE tab.tableName = 'MYTABLE' AND ColumnName = 'TABLEID'
> I'm pulling in data for which I need to preserve the ID's:
> INSERT INTO MYTABLE (TableId, StringValue) VALUES (1, 'test1')
> INSERT INTO MYTABLE (TableId, StringValue) VALUES (2, 'test2')
> INSERT INTO MYTABLE (TableId, StringValue) VALUES (3, 'test3')
> In the absense of the Derby 10.2 feature (ALTER TABLE WITH RESTART X), I try to just change the INCREMENT BY value and insert a row so that I can reset the "next" key value:
> ALTER TABLE MyTable ALTER TableId SET INCREMENT BY 50
> Then I insert a "dummy" record (which I will delete later...) to move the key upwards:
> INSERT INTO MYTABLE (StringValue) VALUES ('test53')
> However, I can now no longer insert explicit values into the primary key like this:
> INSERT INTO MYTABLE (TableId, StringValue) VALUES (-999, 'test3')
> I get this error:  SQL Exception: Attempt to modify an identity column 'TABLEID'. 
> Upon checking the sys.syscolumns table again, it verifies that the table no longer has an auto-generated key, but the TableId is still an identity column.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira