DROP DEFAULT (Transact-SQL)
Removes one or more user-defined defaults from the current database.
DROP DEFAULT will be removed in the next version of Microsoft SQL Server. Do not use DROP DEFAULT in new development work, and plan to modify applications that currently use them. Instead, use default definitions that you can create by using the DEFAULT keyword of ALTER TABLE or CREATE TABLE.
Before dropping a default, unbind the default by executing sp_unbindefault if the default is currently bound to a column or an alias data type.
After a default is dropped from a column that allows for null values, NULL is inserted in that position when rows are added and no value is explicitly supplied. After a default is dropped from a NOT NULL column, an error message is returned when rows are added and no value is explicitly supplied. These rows are added later as part of the typical INSERT statement behavior.
A. Dropping a default
If a default has not been bound to a column or to an alias data type, it can just be dropped using DROP DEFAULT. The following example removes the user-created default named datedflt.
USE AdventureWorks2012; GO IF EXISTS (SELECT name FROM sys.objects WHERE name = 'datedflt' AND type = 'D') DROP DEFAULT datedflt GO
B. Dropping a default that has been bound to a column
The following example unbinds the default associated with the EmergencyContactPhone column of the Contact table and then drops the default named phonedflt.
USE AdventureWorks2012; GO IF EXISTS (SELECT name FROM sys.objects WHERE name = 'phonedflt' AND type = 'D') BEGIN EXEC sp_unbindefault 'Person.Contact.Phone' DROP DEFAULT phonedflt END GO