GetColumnSQLVARIANT Method

2008-12-15

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 GetColumnSQLVARIANT method retrieves a sql_variant column as an array of bytes.

语法

object
.GetColumnSQLVARIANT( 
Row
, 
Column
)
as Byte

Parts

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

Row
Long integer that identifies a row by ordinal position.

Column
Long integer that identifies a column by ordinal position.

Prototype (C/C++)

HRESULT GetColumnSQLVARIANT(
long lRow, 
long lColumn, 
LPVOID *pvData);

Returns

A sql_variant representation of the value of a QueryResults2 object result set member

备注

GetColumnSQLVARIANT returns the contents of a sql_variant column in a typeless form. An application written in C++ can then cast the contents of the array into the required data type.

Prior to calling GetColumnSQLVARIANT, call GetColumnSQLVARIANTDataType to retrieve the underlying data type of the specified sql_variant column, and then call the GetColumnSQLVARIANTLength method to determine the number of bytes in the column.

Examples

//Retrieve the underlying data type and number of bytes in the column.
//Then return the contents of the column.
SQLDMO_BSTR str;
Long                    lLen;
Void *                  pRetVal;
pQueryRes2out->GetColumnSQLVARIANTDataType(0, 0, _T("T1"),  &str);
pQueryRes2out->GetColumnSQLVARIANTLength(0, 0, _T("T1"),  &lLen);
pQueryRes2out->GetColumnSQLVARIANT(0, 0,  &pRetVal);
_tprintf(TEXT("%s\n"), (TCHAR *)pRetVal);
CoTaskMemFree(pRetVal);

注意：
If an application calls GetColumnSQLVARIANT 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 or later" are returned.