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Posted to derby-dev@db.apache.org by "Bryan Pendleton (JIRA)" <ji...@apache.org> on 2006/11/12 01:39:40 UTC
[jira] Commented: (DERBY-1645) ALTER TABLE ... SET INCREMENT BY
X... Turns off the "Generated By Default" identity column constraint
[ http://issues.apache.org/jira/browse/DERBY-1645?page=comments#action_12449066 ]
Bryan Pendleton commented on DERBY-1645:
----------------------------------------
I have attached a proposed patch to DERBY-1495 which also addresses this problem, I believe.
The proposed patch is slightly different from that suggested by Saurabh; I modified the
bindAndValidateDefault method in ModifyColumnNode to populate the defaultInfo as needed.
> 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
>
> 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.
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