Dropping foreign key using variable as name

Question

I use the following:

DECLARE @ConstraintName varchar(255);
SELECT @ConstraintName = CONSTRAINT_NAME 
FROM 
   INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE 
WHERE 
         


        

Answer 1

Try this :

DECLARE @ConstraintName VARCHAR(255);
SELECT CONSTRAINT_NAME 
INTO @ConstraintName 
FROM 
   INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE 
WHERE 
   TABLE_NAME = 'TheTable' 
   AND COLUMN_NAME = 'TheColumn';

alter table TheTable drop constraint @ConstraintName;

Or :

DECLARE @ConstraintName VARCHAR(255);
SELECT @ConstraintName:=CONSTRAINT_NAME 
FROM 
   INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE 
WHERE 
   TABLE_NAME = 'TheTable' 
   AND COLUMN_NAME = 'TheColumn';

alter table TheTable drop constraint @ConstraintName;