Conurrency in Insert sql

[Giò]

Hi,
I have a Table like this:
CREATE TABLE MYTABLE( ID_PK INTEGER NOT NULL, DATE_INI DATE, DATE_END DATE)
I need to polulate my table with data but each record cannot contain
overlapped date.
Example:
1, 10-10-2005, 10-12-2005
2, 10-13-2005, 10-15-2005. Correct

1, 10-10-2005, 10-12-2005
2, 10-11-2005, 10-15-2005. Incorrect.

With a single client this is simple, but if I have two clients in wich way
can I guarantee this rule without lock all table?

Thanks

[Jeff Overcash (TeamB)]

Post by Giò
Hi,
CREATE TABLE MYTABLE( ID_PK INTEGER NOT NULL, DATE_INI DATE, DATE_END DATE)
I need to polulate my table with data but each record cannot contain
overlapped date.
1, 10-10-2005, 10-12-2005
2, 10-13-2005, 10-15-2005. Correct
1, 10-10-2005, 10-12-2005
2, 10-11-2005, 10-15-2005. Incorrect.
With a single client this is simple, but if I have two clients in wich way
can I guarantee this rule without lock all table?

You will have to lock the table. Your only other option is to always verify
that the record you just committed (you have to do this after the commit)
doesn't violate your rules. You can not get a dirty read transaction level (I
don't know of any DB that implements this transaction level actually) which is
what you'd need to be able to see uncommitted work from other transactions.

Post by Giò
Thanks