Sql server drop all foreign key constraints on a table

while(exists(select 1 from INFORMATION_SCHEMA.TABLE_CONSTRAINTS where CONSTRAINT_TYPE='FOREIGN KEY'))
BEGIN
declare @sql nvarchar(2000)
SELECT TOP 1 @sql=('ALTER TABLE ' + TABLE_SCHEMA + '.[' + TABLE_NAME
+ '] DROP CONSTRAINT [' + CONSTRAINT_NAME + ']')
FROM information_schema.table_constraints
WHERE CONSTRAINT_TYPE = 'FOREIGN KEY'
exec (@sql)




end