Victoria Reznichenko wrote:
>On Friday 04 April 2003 15:37, Grégoire Dubois wrote:
>
>
>
>>In the following table, I declare ID as a PRIMARY KEY. Is it then
>>necessary to add the parameters NOT NULL AUTO_INCREMENT?
>>
>>CREATE TABLE company (
>> ID INT NOT NULL AUTO_INCREMENT,
>>
>> name VARCHAR(30),
>>
>> admin_ID INT,
>>
>> PRIMARY KEY ID,
>> INDEX admin_ID,
>>);
>>
>>Or can I just declare the table like that? Does creating a primary key
>>on an int immediatly involve this one to be not null, and to
>>auto-incrИment?
>>
>>
>
>NOT NULL - yes, but if you want to have AUTO_INCREMENT column you should
>declare it as AUTO_INCREMENT.
>
>
>
>
Thank you very much for your reply.
But I read that a PRIMARY KEY is a "globally unique identifier" for a
table. As it is an identifier, it should never be null (ok, that's what
you said), and it should be unique... Then, if I don't set
AUTO_INCREMENT to my column ID, it still should be unique, and then
increment itself... No?
