Constraints can be column level or table level. Column level constraints apply to a column, and table level constraints apply to the whole table. The following constraints are commonly used in SQL: …

Jan 30, 2025 · In this article, we will explain the most common SQL constraints in detail, providing clear examples and explaining how to implement them effectively. What Are SQL Constraints?

Sep 22, 2025 · Key Constraints in SQL play a vital role in maintaining data accuracy and integrity in relational databases. They prevent duplicate, NULL, or mismatched values, ensuring that data …

Feb 8, 2023 · In this SQL tutorial, we’ll demonstrate examples for the types of constraints that can be created in Microsoft SQL Server. The T-SQL constraint code can be copied, pasted, and modified for …

To learn more, visit SQL UNIQUE Constraint. The PRIMARY KEY constraint is simply a combination of NOT NULL and UNIQUE constraints. It means that the column value is used to uniquely identify the …

Nov 18, 2025 · Primary keys and foreign keys are two types of constraints that can be used to enforce data integrity in SQL Server tables. These are important database objects. A table typically has a …

Jul 19, 2025 · SQL Constraints are rules enforced on data columns in a database table. They help ensure the accuracy, consistency, and reliability of the data stored in a database.

SQL constraints are rules enforced on data columns in SQL Server databases. They ensure the accuracy and reliability of the data in the database. By restricting the type of data that can be stored …

SQL constraints define rules for the data in a database to maintain accuracy, consistency, and integrity. They ensure that only valid data is stored, preventing issues like duplicate entries, missing values, or …