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AllowNulls Property

后续版本的 Microsoft SQL Server 将删除该功能。 请避免在新的开发工作中使用该功能，并着手修改当前还在使用该功能的应用程序。

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

语法

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);

注释

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.