Re: Adding Foreign Key Constraint To Existing Table
От | Thom Brown |
---|---|
Тема | Re: Adding Foreign Key Constraint To Existing Table |
Дата | |
Msg-id | BANLkTi=f64Y314Tntn3sA86JLR15rPJ2sA@mail.gmail.com обсуждение исходный текст |
Ответ на | Adding Foreign Key Constraint To Existing Table (Rich Shepard <rshepard@appl-ecosys.com>) |
Список | pgsql-general |
On 1 July 2011 22:00, Rich Shepard <rshepard@appl-ecosys.com> wrote: > I've examined the 9.0 manual page on alter table without seeing how to add > a foreign key constraint to a column. > > I needed to make changes on a couple of existing tables which could be > accomplished only by dropping the foreign key constraint. That, and changing > the table structure, column names, and column types were successful. But, I > am not seeing the proper syntax to add a foreign key constraint back to the > two affected tables. ALTER TABLE table_a ADD CONSTRAINT fk_name FOREIGN KEY (column_of_table_a) REFERENCES table_b (column_of_table_b); If in future you want foreign key checks to be deferred until the transaction ends, you can add the DEFERRED keyword to the end. This will allow you to violate the foreign key temporarily, as long as you resolve it before the end of the transaction. -- Thom Brown Twitter: @darkixion IRC (freenode): dark_ixion Registered Linux user: #516935 EnterpriseDB UK: http://www.enterprisedb.com The Enterprise PostgreSQL Company
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