如何一步删除主键？

Question

I would like to drop the primary key for a table, but keep the column (I know the name of the column, if it helps).

I use this script to get the name of the primary key:

-- Return the name of primary key.  
SELECT key_name  
FROM sys.key_constraints  
WHERE type = 'PK' AND OBJECT_NAME(parent_object_id) = 'my_table'; 

Then I remove the key like this:

ALTER TABLE Production.TransactionHistoryArchive  
DROP CONSTRAINT key_name ;   

It works, but I have to run this script in one go. How it is possible to combine drop constraint with a select query?

Answer 1

Will throw this out there in case it's useful to you. Using Dynamic SQL you can build something that you could easily create a procedure for.

declare @Schema nvarchar(20)=N'Production',
  @Table nvarchar(50)=N'TransactionHistoryArchive',
  @sql nvarchar(100)=''

select @sql='ALTER TABLE ' 
  + QuoteName(@Schema) + '.'
  + QuoteName(@Table) 
  + ' DROP CONSTRAINT ' 
  + QuoteName(name)
from sys.key_constraints  
where type = 'PK' and Object_Name(parent_object_id) = @Table and [schema_id]=Schema_Id(@Schema)

print @sql
exec sp_executesql @sql