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);
备注
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:
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