覆寫動態存取子
當您使用 CDynamicAccessor 這類的動態存取子時，Open 命令的方法會自動地為您根據已開啟資料列集的資料行資訊，建立一個存取子。您可以覆寫動態存取子以便確實地控制資料行的繫結方式。
若要覆寫這個動態存取子，請將 false 當成最後一個參數傳遞給 CCommand::Open 方法。這樣便可以避免 Open 自動建立存取子。然後您可以為每個要繫結的資料行呼叫 GetColumnInfo 和呼叫 AddBindEntry。請參見下列範例程式碼：
USES_CONVERSION;
double dblProductID;
CCommand<CDynamicAccessor> product;
// Open the table, passing false to prevent automatic binding
product.Open(session, _T("Select * FROM Products"), NULL, NULL, DBGUID_DEFAULT, false);
ULONG nColumns;
DBCOLUMNINFO* pColumnInfo;
// Get the column information from the opened rowset.
product.GetColumnInfo(&nColumns, &pColumnInfo);
// Bind the product ID as a double.
pColumnInfo[0].wType = DBTYPE_R8;
pColumnInfo[0].ulColumnSize = 8;
product.AddBindEntry(pColumnInfo[0]);
// Bind the product name as it is.
product.AddBindEntry(pColumnInfo[1]);
// Bind the reorder level as a string.
pColumnInfo[8].wType = DBTYPE_STR;
pColumnInfo[8].ulColumnSize = 10;
product.AddBindEntry(pColumnInfo[8]);
// You have finished specifying the bindings. Go ahead and bind.
product.Bind();
// Free the memory for the column information that was retrieved in
// previous call to GetColumnInfo.
CoTaskMemFree(pColumnInfo);
char* pszProductName;
char* pszReorderLevel;
bool bRC;
// Loop through the records tracing out the information.
while (product.MoveNext() == S_OK)
{
bRC = product.GetValue(1, &dblProductID);
pszProductName = (char*)product.GetValue(2);
pszReorderLevel = (char*)product.GetValue(9);
ATLTRACE(_T("Override = %lf \"%s\" \"%s\"\n"), dblProductID,
A2T(pszProductName), A2T(pszReorderLevel));
}