A database is only as good as the design of its tables and the constraints placed on them. In this article, we will discuss key constraints in dbms and how they impact database design.
What should I know about this?
A key constraint is a restriction that you place on a column or group of columns in a table. There are three types of key constraints: primary key, foreign key, and unique key. Let’s take a look at each one.
The primary constraint is the most important constraint in a database. It ensures that every row in a table has a unique identifier. The primary key can be any data type, but it is usually an integer or GUID (Globally Unique ID). The primary key cannot contain NULL values.
The foreign constraint links two tables together. It ensures that the data in the child table matches the data in the parent table.
We hope this information has been useful to you.