This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.
The AlterDataType method alters the data type of the referenced column.
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.
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.