SQL PRIMARY KEY CONSTRAINT AND CLUSTERED INDEX | STEP BY STEP SOLUTION TO SQL INTERVIEW QUESTION

This is the third of 6 videos I have created on SQL Server constraints.

The Primary Key constraint ensures that a column or more columns
uniquely identify a row in a table. It is a combination of NOT NULL and UNIQUE constraints. Helps to easily retrieve records from a table (s) by enforcing a Clustered Index on the table.

A clustered index defines the ordering of data is stored in a table. Table data can be sorted in only one way, therefore, there can be only one clustered index per table thus one Primary Key constraint on a table.

SQL constraints are rules specified on database tables and/or columns to restrict the data entered into a table.
If we set constraints on a table and any violation between the constraint and the data, the action is aborted.
This is important in a relational database because it ensures the data's accuracy and reliability in the table.