AllowNulls Property

未來的 Microsoft SQL Server 發行版本將不再提供此功能。請避免在新的開發工作中使用此功能，並計劃修改目前使用此功能的應用程式。

The AllowNulls property exposes the ability of a data type to accept NULL as a value.

語法

object
.AllowNulls [=value]

Parts

• object
  An expression that evaluates to an object in the Applies To list

• value
  TRUE or FALSE

Data Type

Boolean

Modifiable

Read-only for SystemDatatype objects. Read/write for Column and UserDefinedDatatype objects.

Prototype (C/C++)

HRESULT GetAllowNulls(LPBOOL pRetVal);
HRESULT SetAllowNulls(BOOL NewValue);

備註

If TRUE, the Microsoft SQL Server data type or column referenced can accept NULL as a value.

If FALSE, NULL is not allowed.

Set the AllowNulls property to set NULL as an accepted value for columns and user-defined data types.

Applies To: