I have a table GB_Assignor_Assignee. I have a primary key which includes this combination(StateCode, CountyID, Doc_Type_Group_Code). Now i have to add a new column Doc_Type_Code. I added it by altering table. I want to include this new column inside this primary key.So my combination will be(StateCode, CountyID, Doc_Type_Group_Code,Doc_Type_Code).
How can i alter this primary key to add new column. I donot want to drop it and then recreate it. Please suggest.
If you want to change the primary key to include a new column, you have to drop and recreate it – there’s no other way. You cannot add a column to an existing primary key after it’s been created.
The question is: wouldn’t you be better off creating a new artificial ID (of type INT) as your PK? You wouldn’t have to change it if yet another column comes along, referencing the table will be MUCH easier (JOIN on just a single INT instead of five or six columns)……