如何使用主键而不是自动增量创建MySQL

Question

Am trying to create the following table:

create table Cust (Name varchar(50) UNIQUE, Cat1 varchar(50), RowID int NOT NULL AUTO_INCREMENT, PRIMARY KEY (Name));

the error I get is

Incorrect table definition; there can be only one auto column and it must be defined as a key

I want to index by the "Name", not the RowID. So even if I end it with:

...PRIMARY KEY (Name, RowID));

It fails. Of course ...PRIMARY KEY (RowID, Name)); works but is not what I want.

Can someone help me see the light please?

Thanks

Answer 1

You just need to make a KEY (aka index) for the auto-inc column. It doesn't have to be the primary key, but it must be the left-most column in some index.

create table Cust (
  Name varchar(50), 
  Cat1 varchar(50), 
  RowID int NOT NULL AUTO_INCREMENT, 
  PRIMARY KEY (Name),
  KEY (RowId)
);

Don't add the UNIQUE option to the name column. That creates an extra superfluous unique index, which you don't need. Any PRIMARY KEY is already unique.

I'll comment that auto-inc is not the same thing as rowid. Don't expect auto-inc to have consecutive values.