Default Object

Questa caratteristica verrà rimossa a partire da una delle prossime versioni di Microsoft SQL Server. Evitare di utilizzare questa caratteristica in un nuovo progetto di sviluppo e prevedere interventi di modifica nelle applicazioni in cui è attualmente implementata.

The Default object represents the attributes of a single default in Microsoft SQL Server 2000 or later. SQL Server defaults provide data to columns and user-defined data types when no other data is available on an INSERT statement execution.

Properties

CreateDate Property	Owner Property (Database Objects)
ID Property	Text Property
Name Property

Methods

BindToColumn Method	Remove Method (Objects)
BindToDatatype Method	Script Method
ListBoundColumns Method	UnbindFromColumn Method
ListBoundDatatypes Method	UnbindFromDatatype Method

Osservazioni

SQL Server defaults allow a non-redundant method of default-value specification. SQL Server columns can contain a DEFAULT constraint, but each column receiving a specific default value must be constrained to receive it. Alternately, a single default can be created and then bound to columns or user-defined data types, allowing the developer to specify the default value one time.

With the Default object, you can:

• Create a SQL Server default.

• Bind or unbind an existing SQL Server default to a column or user-defined data type.

• Remove a SQL Server default from a database.

The Name property of a Default object uses the SQL Server data type sysname. The value of the Name property must be unique within a SQL Server database when constrained by the value of the Owner property.

To create a SQL Server default

1. Create a Default object.

2. Set the Name property.

3. Set the Text property to establish the default value generated for an INSERT statement. The value of the Text property must match the constraints of the constant_expression parameter of the CREATE DEFAULT statement. For more information about how to set the Text property, see CREATE DEFAULT (Transact-SQL).

4. Add the Default object to the Defaults collection of a connected Database object.

After the SQL Server default has been created, use the BindToColumn and BindToDatatype methods of the Default object to bind the SQL Server default to SQL Server columns and user-defined data types.

Nota

The Default object is compatible with SQL Server 7.0 and later. However, the Default2 object extends the functionality of the Default object for use with features that were introduced in SQL Server 2000.

Vedere anche

Riferimento

Default2 Object