In SQL we have three four major constraints - 'UNIQUE', 'FOREIGN KEY', 'CHECK' and 'NOT NULL'. Also we have non-standard ON CONFLICT clause, which propose what kind ...

Constraints in SQL are used to define rules for the table and columns in a database and also make sure that data are accurate and trusted in the database. Constraints are responsible for the ...

Cascading referential integrity constraints are foreign key constraints that tell SQL Server to perform certain actions when a primary key field in a primary key-foreign key relationship is updated or ...

Redefine an SQL constraint on your module Update your module Create a record that violates the old constraint, but not the new one Update your module again If you want to have it, you should update ...