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 AlterDataType method alters the data type of the referenced column.
语法
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);
备注
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.
.gif "ms144573.note(zh-cn,SQL.90).gif") 注意： |
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| 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. |