UNIQUE Constraint

UNIQUE constraints in SQLite ensure that a column or group of columns should not accept duplicate values. Simply, it prevents us from entering duplicate values in a column or group of columns.

Suppose, We create a table ‘student’. It consists of name, roll, and rank. As for its columns, we do not want the rank column to accept duplicate values but it can accept null values. Now, in this type of scenario, we can take the use of UNIQUE constraints into action.

Syntax :

CREATE TABLE table_name(

column_name datatype UNIQUE

);

SQLite UNIQUE Constraint

SQLite is a lightweight relational database management system (RDBMS). It requires minimal configuration and it is self-contained. It is an embedded database written in C language. It operates a server-less, file-based database engine making it a good fit for mobile applications and simple desktop applications. It supports standard SQL syntax. In this article, we are going to cover all the necessary points of UNIQUE constraint. This article will cover every possible use of UNIQUE constraints.

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Conclusion

Unique Constraint is a crucial part of relational database system (RDBMS). It gives us flexibility to make our columns to accept only unique values. However, unlike primary key we can add NULL values in our Unique columns. We can also have more than one unique columns in our table. Unique constraint ensures us that our columns should not accept any duplicate values....

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