primary key definition

  • in my concise 229 book, to define a primary key as follows:

    create table table1

    abc1 int primary key

    ...

    and another way

    ab1 int

    constraint table_pk primary key(abc1)

    so what is "table_pk"?

  • table_pk is the primary key constraint name. In this case they are using the table name plus "_PK" to make up the name. Therefore if your table was called tblEmployee, the Primary key of that table would be "tblEmployee_pk" using their format. If a constraint name is not specified, the database will automatically generate one (as in the first instance).

  • The _pk is what is known as a "naming convention". It identifies that name as a primary key. Other conventions are udf_functionname. udf is short for user defined function. sp is stored procedure. ETC.

    -SQLBill

  • Primary Keys are stored as constraint objects within a database. All objects must have names, as mentioned in a previous post, the names should be meaningful and follow a naming convention. If you are bored, run the following script:

    use northwind

    select * from sysobjects where xtype = 'pk'

    It will list all the PKs in the northwind database.

Viewing 4 posts - 1 through 3 (of 3 total)

You must be logged in to reply to this topic. Login to reply