问题
Snowflake allows UNIQUE, PRIMARY KEY, FOREIGN KEY and NOT NULL constraints but I read that it enforces only NOT NULL constraint. Then what is the purpose of other keys and under what circumstances do we have to define them? I appreciate any examples.
Thank you, Prashanth.
回答1:
They express intent, helping people understand your data models. Data modeling tools can use them to generate diagrams. You can also programmatically access them to validate data integrity yourself.
来源：https://stackoverflow.com/questions/59725414/significance-of-constraints-in-snowflake