10/28/2023 0 Comments Postgres ondeleteIn addition to foreign keys, there are primary keys that uniquely identify a given row, unique constraints ensuring uniqueness, not-null, and check constraints.įoreign keys are helpful when you reference data living in another table or row. If this sounded a bit too academic, let’s break down every part of this statement.Ĭonstraints are, as the name says, ways to constrain data in your database to match your expectations. □ A brief recap on Foreign Keysįoreign key constraints are the standard measure to ensure referential integrity in relational databases. In this guide, we’ll walk through all options you have when configuring foreign key constraints, how you can detect the mode an existing foreign key constraint is set to, and how to model your data around these concepts.įor the remainder of the guide, we’ll walk over most parts of the foreign key creation grammar, so it might be helpful to keep the following in mind PostgreSQL offers a wide range of options for foreign keys, including marking foreign key constraints as deferrable in complex cases. Sometimes, rows referencing deleted or updated entities should stay around, sometimes, the deletion process should cascade and include all referencing rows, too. You might have experienced a scenario where a traditional foreign key constraint would be violated, for example, when creating circular references or having multiple entities depend on a resource where all rows are dropped at once. If you can spare 30 minutes of your time, I'd love to chat with you! Just send me an email! Hey there □ I would love to learn more about your thoughts on onboarding software engineers and the challenges you're facing in your company.
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