4. Move through all records in the recordset, calling [CComboBox::AddString](../Topic/CComboBox::AddString.md) for each string from the current record you want to add to the combo box.

Similarly, the database classes shield you from having to work much with [SQL](../../data/odbc/sql.md), but you can use SQL directly if you want. You can customize recordset objects by passing a custom SQL statement (or setting portions of the default statement) when you open the recordset. You can also make SQL calls directly using the [ExecuteSQL](../mfc/reference/cdatabase-class.md#cdatabase__executesql) member function of class [CDatabase](../../mfc/reference/cdatabase-class.md).

The wizards use a default connection string to establish a connection to a data source. You use this connection to view tables and columns while you are developing your application. However, this default connection string might not be appropriate for your users' connections to the data source through your application. For example, their data source and the path to its location might be different from the one used in developing your application. In that case, you should reimplement the [CRecordset::GetDefaultConnect](../mfc/reference/crecordset-class.md#crecordset__getdefaultconnect) member function in a more generic fashion and discard the wizard implementation. For example, use one of the following approaches:

If the cursor library is used, it masks some functionality of the underlying ODBC driver that is necessary for dynaset support. If you want to use dynasets (and your ODBC driver has the functionality required for dynasets, as described in the rest of this section), you can cause MFC not to load the cursor library when you create a `CDatabase` object. For more information, see [ODBC](../../data/odbc/odbc-basics.md) and the [OpenEx](../mfc/reference/cdatabase-class.md#cdatabase__openex) or [Open](../mfc/reference/cdatabase-class.md#cdatabase__open) member function of class `CDatabase`.

In addition to these steps, you need to take extra steps to check function return values, ensure that your program is not waiting for an asynchronous call to finish, and so on. You can simplify these last steps by using the `AFX_SQL_ASYNC` and `AFX_SQL_SYNC` macros. For more information, see [Macros and Globals](../Topic/Macros,%20Global%20Functions,%20and%20Global%20Variables.md) in the *MFC Reference*.

The second issue concerns limitations of class [CTime](../../atl-mfc-shared/reference/ctime-class.md) when used with the `RFX_Date` function to transfer time and date information to or from a table. Processing the `CTime` object imposes some overhead in the form of extra intermediate processing during the data transfer. The date range of `CTime` objects might also be too limiting for some applications. A new version of the `RFX_Date` function takes an ODBC **TIMESTAMP_STRUCT** parameter instead of a `CTime` object. For more information, see `RFX_Date` in [Macros and Globals](../Topic/Macros,%20Global%20Functions,%20and%20Global%20Variables.md) in the *MFC Reference*.

When you connect to a data source — by calling [CDatabase::OpenEx](../mfc/reference/cdatabase-class.md#cdatabase__openex) or [CDatabase::Open](../mfc/reference/cdatabase-class.md#cdatabase__open) — you can specify whether to use the cursor library for the data source. If you will be creating snapshots on that data source, specify the **CDatabase::useCursorLib** option in the `dwOptions` parameter to `OpenEx` or specify **TRUE** for the **bUseCursorLib** parameter to **Open** (the default value is **TRUE**). If your ODBC driver supports dynasets and you want to open dynasets on the data source, do not use the cursor library (it masks some driver functionality needed for dynasets). In that case, do not specify **CDatabase::useCursorLib** in `OpenEx` or specify **FALSE** for the **bUseCursorLib** parameter in **Open**.