Check constraint to prevent insertion of invalid characters.

A column level check constraint may be used to prevent insertion of data containing characters within a specific ASCII range.

NULLs to Not NULLs

Script finds char types columns defined to allow NULL values but have non NULL values and generates the ALTER statements for the changes.

Declarative SQL: Using CHECK() & DEFAULT

SQL is unusual is that data is not passively stored. Instead you use declarative SQL to specify the rules that underlie the data and its integrity. When used properly, constraints can avoid having to provide a lot of logic elsewhere. CHECK() and DEFAULT can do a lot to ensure that your data is correct

Declarative SQL: Using UNIQUE Constraints

In SQL, you can express the logic of what you want to accomplish without spelling out the details of how the database should do it. Nowhere is this more powerful than in constraints. In this introduction to Declarative SQL, Joe Celko demonstrates how you can write portable code that performs well and executes some complex logic, merely by creating unique constraints.

Constraints renaming

Rename constraints to enforce naming conventions.

Obedience Training For Databases: Cascading Constraints

In which Phil Factor illustrates in TSQL how it is possible to use foreign key constraints to enforce data rules, and illustrates some surprising consequences of using cascading.

Set-based Constraint Violation Reporting in SQL Server

When you're importing data into an RDBMS in bulk and an exception condition is raised because of a constraint violation, you generally need to fix the problem with the data and try again. The error won't tell you which rows are causing the violation. What if you've thousands of rows to search when it happens? There are solutions, writes William Sisson.

T- SQL Constraints

Code For Truncating Table with foreign Key Constraints

This can be used for data warehouses as well as truncating table with foreign key constraints.

It's Not All About The Keys