Postgresql foreign key on update

While updating the non key column values, we could force the behavior to not hold any lock on the key columns. In some cases, we may really require to hold a lock on the key columns. This is required to maintain the data consistency across the parent and child tables. Then, the FOR UPDATE will may avoid the deadlock problems but it is going to block a huge number of key values, which will make all the child table transactions to go into the waiting state.

It may be a good approach for some of the application but when you see the locking causing more damages, we may need to approach this with pessimistic locking achieved through advisory locks.

We shall look into advisory locks and how it can be efficiently as part of our next article. Meanwhile, if you have have any performance problems with PostgreSQL or need support in migrating to PostgreSQL, please contact us or you may fill the following form. Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community.

It only takes a minute to sign up. Connect and share knowledge within a single location that is structured and easy to search. I am a new one in postgreSQL. I have 3 tables, one table references the other 2 table's primary keys. But I couldn't insert data into the Table3.

See the code below :. When I tried to insert data into the 3 tables, an error occured. I referred the postgreSQL documentation and changed my code as follows: Unfortunately it showed another error. At that time it shows another error like :. There are a few problems with your tables.

I'll try to address the foreign keys first, since you question asked about them :. But before that, we should realize that the two sets of tables the first three you created and the second set, which you created after dropping the first set are the same. Of course, the definition of Table3 in your second attempt has syntax and logical errors, but the basic idea is:.

If there is no such value in those tables, then return an error. If this seems to you not what you want, please describe in a few sentences what you want to achieve, and we can help with a good design.

This is what you got in your third error message. Furthermore, '0' means a text string, but not a number bigint or numeric in your case. A table can possess multiple foreign keys according to its relationships with other tables.

If you omit it, PostgreSQL will assign an auto-generated name. The delete and update actions determine the behaviors when the primary key in the parent table is deleted and updated. PostgreSQL supports the following actions:. Each customer has zero or many contacts and each contact belongs to zero or one customer.

Skip to content. Change Language. Related Articles. Database Operations. Community Bot 1 1 1 silver badge. Patrick Desjardins Patrick Desjardins k 82 82 gold badges silver badges bronze badges. Arthur's comment. Mark Brady Mark Brady. I don't think this is a problem if the schema is designed correctly. That's a reasonable statement.

But the more things that occur without intent the less successful the database. When a DB can operate without an app -- direct data load, direct query access etc. In my experience, junior developers tend to treat the DB as controlled by an app, while senior developers who have been burned too many times design the DB to stand on its own. Remember, DBs can live on long after the app is gone. This is just the principle of encapsulation, applied to databases.

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