创建SQL身份作为主键？

Question

create table ImagenesUsuario
{
    idImagen int primary key not null IDENTITY
}

This doesn't work. How can I do this?

Answer 1

Simple change to syntax is all that is needed:

 create table ImagenesUsuario (
   idImagen int not null identity(1,1) primary key
 )

By explicitly using the "constraint" keyword, you can give the primary key constraint a particular name rather than depending on SQL Server to auto-assign a name:

 create table ImagenesUsuario (
   idImagen int not null identity(1,1) constraint pk_ImagenesUsario primary key
 )

Add the "CLUSTERED" keyword if that makes the most sense based on your use of the table (ie, the balance of searches for a particular idImagen and amount of writing outweighs the benefits of clustering the table by some other index).

Answer 2

This is similar to the scripts we generate on our team. Create the table first, then apply pk/fk and other constraints.

CREATE TABLE [dbo].[ImagenesUsuario] (
    [idImagen] [int] IDENTITY (1, 1) NOT NULL
)

ALTER TABLE [dbo].[ImagenesUsuario] ADD 
    CONSTRAINT [PK_ImagenesUsuario] PRIMARY KEY  CLUSTERED 
    (
        [idImagen]
    )  ON [PRIMARY] 

Answer 3

If you're using T-SQL , the only thing wrong with your code is that you used braces {} instead of parentheses () .

PS: Both IDENTITY and PRIMARY KEY imply NOT NULL , so you can omit that if you wish.