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Is it possible to create a table in MYSQL where more then one fields can be defined as Primary key ?

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Is it possible to create a table in MYSQL where more then one fields can be defined as Primary key ?
posted Apr 17, 2017 by Ajay Shetty

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2 Answers

0 votes

I hope I understood your question correctly -
1) One table can not have more then one primary key.

create table User(
   name  TEXT  NOT NULL , 
   email  TEXT  NOT NULL ,
   PRIMARY KEY (email)
);

2) Its possible to have one primary key and rest as keys (unique key).

create table User(
   name  TEXT  NOT NULL , 
   email  TEXT  NOT NULL ,
   PRIMARY KEY (email),
   KEY (email)
);

3) Its also possible to have a combination of two column as a single primary key where individual value can be repeated in the same table but not the combination

create table User(
   name  TEXT  NOT NULL , 
   email  TEXT  NOT NULL ,
   PRIMARY KEY (name, email)
);
answer Apr 17, 2017 by Salil Agrawal
0 votes

Hi...

In MySql there is not possible to two primary key in same table. but you can use multiple unique key in same table.

example:

create table User(
   name  TEXT  NOT NULL , 
   email  TEXT  NOT NULL ,
   PRIMARY KEY (email)
);
answer Nov 27 by Siddhi Patel
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