---
title: "What are Constraints in SQL?"  
description: "What are Constraints in SQL?"  
author: "Anonymous User"  
published: 2019-09-16  
updated: 2020-09-14  
canonical: https://www.mindstick.com/interview/33616/what-are-constraints-in-sql  
category: "mssql server"  
tags: ["sql server"]  
reading_time: 1 minute  

---

# What are Constraints in SQL?

Those constraints are used to specify the limit on the data type of the table. That can be specified while creating or altering the table statement. The sample of constraints are:

- NOT NULL
- CHECK
- DEFAULT
- UNIQUE
- PRIMARY KEY
- FOREIGN KEY

## Answers

### Answer by Anonymous User

Those constraints are used to specify the limit on the data type of the table. That can be specified while creating or altering the table statement. The sample of constraints are:

- NOT NULL
- CHECK
- DEFAULT
- UNIQUE
- PRIMARY KEY
- FOREIGN KEY


---

Original Source: https://www.mindstick.com/interview/33616/what-are-constraints-in-sql

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