Declarative Defaults

A declarative default is a constraint defined as part of the table definition. Using declarative defaults is the preferred method for assigning default values to columns. You can use the CREATE TABLE or ALTER TABLE statement to create a default and assign it to a column. Declarative defaults are assigned to a single column and cannot be reused for other columns in the database. The following example shows the creation of a new column named CustomerType in the SalesCustomer table followed by the creation of a new default on that column:

ALTER TABLE Sales.Customer ADD CustomerType CHAR(1)ALTER TABLE Sales.Customer ADD CONSTRAINT    DF_Customer_CustomerType DEFAULT 'I' FOR CustomerType

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