The best SQL DEFAULT Constraint Tutorial In 2024, In this tutorial you can learn SQL DEFAULT Constraint,SQL DEFAULT constraint CREATE TABLE when,SQL DEFAULT constraint ALTER TABLE when,Undo DEFAULT constraint,
DEFAULT constraint is used to insert the default value to the column.
If no other value is specified, then the default value will be added to all new records.
The following SQL when the "Persons" table is created to create a DEFAULT constraint on the "City" columns:
My SQL / SQL Server / Oracle / MS Access:
By using such a function similar GETDATE (), DEFAULT constraint can also be used to insert system values:
When the table has been created, create a DEFAULT constraint for a column in the "City", please use the following SQL:
MySQL:
SQL Server / MS Access:
Oracle:
To drop a DEFAULT constraint, use the following SQL:
MySQL:
SQL Server / Oracle / MS Access: