How to add a default value to an already existing column?
Use: ALTER TABLE dbo.mytable ADD CONSTRAINT def_mycolumn DEFAULT GETDATE() FOR mycolumn For more info, see: Working with Default Constraints
default-constraint
default a column with empty string
Yes – use a DEFAULT constraint: DROP TABLE IF EXISTS `example`.`test`; CREATE TABLE `example`.`test` ( `string_test` varchar(45) NOT NULL DEFAULT ” ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Command for adding a default constraint
Pretty much, yes for an ALTER TABLE You can add a columnn with default in one step for CREATE or ALTER too. ALTER TABLE dbo.TableName ADD bar varchar(100) CONSTRAINT DF_Foo_Bar DEFAULT (‘bicycle’); ALTER TABLE dbo.TableName ADD bar varchar(100) DEFAULT (‘bicycle’); As you noted, the system generates a name if one is not supplied. CONSTRAINT constraint_name … Read more