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AllowNulls Property

未來的 Microsoft SQL Server 版本將移除這項功能。請避免在新的開發工作中使用這項功能，並規劃修改目前使用這項功能的應用程式。

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.