Constraint sql server example It ensures that all values in one or more columns meet some specific conditions. Table of Contents. In SQL Server, a check constraint is used to specify the limitation on the values of a column when inserting or updating. Developers can use these constraints to enforce rules that ensure data integrity and prevent inconsistencies. What is PRIMARY KEY in SQL Server? A PRIMARY KEY is the hallmark of a RDBMS. In SQL Server Data Tools (SSDT), open the Integration Services project that contains the package you want. Constraints in SQL Server are predefined rules and restrictions that are enforced in a single column or multiple columns, regarding the values allowed in the columns, to maintain the integrity, accuracy, and reliability of that column’s data. check_constraints chk inner join sys. This creates a relationship between the two tables, ensuring that the child table (which contains the foreign key) can only have values that exist in the parent table’s primary key column(s). However, if the whole reason you needed to disable the constraint is to insert data that violates the constraint, then the default WITH NOCHECK is probably what you want.