Home/ Questions/Q 6129063
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-23T16:41:55+00:00

When I use MySQL Workbench to create a simple table with a single primary

  • 0

When I use MySQL Workbench to create a simple table with a single primary key, it not only creates the PK index (cool) but also a second Unique Index (?). Here’s an example output:

CREATE  TABLE  `tbl_example` (
  `tbl_example_ID` INT(10) UNSIGNED NOT NULL ,
  `field1` VARCHAR(45) NULL ,
  `field2` VARCHAR(45) NULL ,
  PRIMARY KEY (`tbl_example_ID`) ,
  UNIQUE INDEX `tbl_example_ID_UNIQUE` (`tbl_example_ID` ASC) )
ENGINE = MyISAM

It’s my understanding that a PK assumes unique index so the UNIQUE INDEX line is unnecessary, correct? Just looking for some confirmation before I update a bunch of tables.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    You are right. A Primary Key is (for MySQL) a unique index with the name ‘PRIMARY KEY’. So having a Primary Key and a unique index on the same column(s) is a pointless waste of resources.

    • 0