AlterDataType Method

發行項
12/15/2008

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 AlterDataType method alters the data type of the referenced column.

語法

object
.AlterDataType(
Datatype
, [ Length ] , [ Precision ] , [ Scale ] )

Parts

object
Expression that evaluates to an object in the Applies To list.

DataType
String that specifies the new data type.

Length
Optional long integer that specifies the length of a string data type.

Precision
Optional long integer that specifies the precision of a numeric data type.

Scale
Optional long integer that specifies the scale of a numeric data type.

Prototype (C/C++)

HRESULT AlterDataType(
SQLDMO_LPCSTR DataType, 
long Length,
long Precision,
long Scale);

備註

When using AlterDataType to convert the data type of an existing column to a new data type, the two data types must be compatible. For example, an int data type can be converted to a decimal data type, and a char data type can be converted to an nvarchar data type. However string data types cannot be converted to numeric data types.

附註：
If an application calls AlterDataType on an instance of SQL Server version 7.0, the constant, SQLDMO_E_SQL80ONLY, and the message "This property or method requires Microsoft SQL Server 2000" are returned.