|SQL - Structured Query Language|
Primary Key Constraint
Primary Key Constraint can define with one column or set of columns that used to identify a Record and to avoid duplicate Records of Table in the Relational Database. Primary Key Constraint must define with Unique, Never Update, Not Null and Sequence Numeric Data Column. Each Table can define with one Primary Key Constraint.
The following SQL Statements are used to create DEPT and EMP Tables with set of constraints.
More Reference URL: https://data-e-education.com/RDBMS/Key_Integrity_Constraints.php
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