PostgreSQL Unique Index

Faruk Erdem

4 months ago

In this article, you will learn how to create a PostgreSQL unique index to ensure the uniqueness of values in one or more columns.

When a primary key is added to a column on a table, uniqueness is also added.

CREATE UNIQUE INDEX indexadi  ON tabloadi (kolonadi );

1	CREATE UNIQUE INDEX indexadi ON tabloadi (kolonadi );

Let’s make an example for UNIQUE index.

First, let’s create a two-column table as follows.

create table uniquetabled1(id int ,adi text)

1	create table uniquetabled1(id int ,adi text)

Let’s assign the index to the id column and perform the insertion operation.

create unique index uniqueindex on uniquetabled1 (id)

1	create unique index uniqueindex on uniquetabled1 (id)

insert into uniquetabled1 values(1,'Faruk')

1	insert into uniquetabled1 values(1,'Faruk')

Let’s check the status of PostgreSQL when we insert the same record again.

As seen above, it is mentioned that there is a record of “1” and that duplicate records cannot be allowed due to the uniqueindex.