Contents of ODBC Readme25.txt File (Part 2 of 2)

The information in this article applies to:

• Microsoft Open Database Connectivity, version 2.5

SUMMARY

Below is the second half of the Microsoft Open Database Connectivity ODBC 2.5 Readme25.txt file, located in the Windows System subdirectory.

NOTE: The first half of the readme25.txt file is located in the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q150150
   TITLE     : Contents of ODBC Readme25.txt File (Part 1 of 2)

MORE INFORMATION

+++++++++++++++SQLConfigDriver+++++++++++++++

Purpose: SQLConfigDriver loads the appropriate driver setup DLL and calls the ConfigDriver function.

Syntax: BOOL SQLConfigDriver (hwndParent, fRequest, lpszDriver, lpszArgs, lpszMsg, cbMsgMax, pcbMsgOut)

Type    Argument        Use     Description

HWND    hwndParent      Input   Parent window handle.
WORD    fRequest        Input   Type of request. fRequest must
                                contain one of the following
                                values:
                                 ODBC_INSTALL_DRIVER:
                                  installing a new driver
                                 ODBC_REMOVE_DRIVER:  removing
                                  a driver
                                This option can also be
                                driver-specific, in which
                                case the first option will
                                be ODBC_CONFIG_DRIVER_MAX+1,
                                and additional options will
                                be incremented by 1 from
                                that value.
LPCSTR  lpszDriver      Input   The name of the driver as
                                registered in the ODBCINST.INI
                                key of the registry.
LPCSTR  lpszArgs        Input   A null-terminated string
                                containing arguments for
                                a driver-specific fRequest.
LPSTR   lpszMsg         Output  A null-terminated string
                                containing an output message
                                from the driver setup.
WORD    cbMsgMax        Input   Length of lpszMsg.
WORD    pcbMsgOut       Output  Total number of bytes
FAR *                           available to return in
                                lpszMsg. If the number of
                                bytes available to return
                                is greater than or equal to
                                cbMsgMax, the output message
                                in lpszMsg is truncated to
                                cbMsgMax-1.

Comments: SQLConfigDriver allows an application to call a driver’s ConfigDriver routine without having to know the name and load the driver-specific setup DLL. A setup program calls this function after the driver setup DLL has been installed. The calling program should be aware that this function may not be available for all drivers. In such a case, the calling program should continue without error.

Driver-Specific Options: An application can request driver- specific features exposed by the driver by using the fRequest argument. The fRequest for the first option will be ODBC_CONFIG_DRIVER_MAX+1, and additional options will be incremented by 1 from that value. Any arguments required by the driver for that function should be provided in a null-terminated string passed in the lpszArgs argument. Drivers providing such functionality should maintain a table of driver-specific options. The options should be fully documented in driver documentation. Application writers who make use of driver-specific options should be aware that this use will make the application less interoperable.

Messages: A driver setup routine can send a text message to an application as null-terminated strings in the lpszMsg buffer. The message will be truncated to cbMsgMax-1 characters by the ConfigDriver function if it is greater than or equal to cbMsgMax characters.

       +++++++++++++++SQLInstallTranslator+++++++++++++++

Syntax: BOOL SQLInstallTranslator (lpszInfFile, lpszTranslator, lpszPathIn, lpszPathOut, cbPathOutMax, pcbPathOut, fRequest, lpdwUsageCount)

Type    Argument        Use     Description

LPCSTR  lpszInfFile     Input   Full path of the ODBC.INF file
                                or a null pointer.
                                If lpszInfFile is a null
                                pointer, lpszTranslator must
                                contain a list of keyword-value
                                pairs describing the
                                translator.
LPCSTR  lpszTranslator  Input   If lpszInfFile is the path of
                                the ODBC.INF file, this must
                                be the key in the ODBC.INF file
                                that describes the translator.
                                If lpszInfFile is a null
                                pointer, this must contain a
                                list of keyword-value pairs
                                describing the translator.
                                The Translator and Setup keywords
                                have to be included in the
                                lpszTranslator string. The
                                translation DLL is listed with
                                the Translator keyword, and the
                                translator setup DLL is listed
                                with the Setup keyword.
LPCSTR  lpszPathIn      Input   Full path of where the
                                translator is to be installed
                                or a null pointer. If lpszPath
                                is a null pointer, then the
                                translators will be installed
                                in the System directory.
LPSTR   lpszPathOut     Output  The path of where the translator
                                should be installed.  If the
                                translator has never been
                                installed, then lpszPathOut is
                                the same as lpszPathIn.  If
                                there exists a prior
                                installation of the translator,
                                then lpszPathOut is the path of
                                the prior installation.
WORD    cbPathOutMax    Input   Length of lpszPathOut.
WORD    pcbPathOut      Output  Total number of bytes
FAR *                           available to return in
                                lpszPathOut. If the number of
                                bytes available to return is
                                greater than or equal to
                                cbPathOutMax, the output path
                                in lpszPathOut is truncated to
                                pcbPathOutMax-1 characters.
WORD    fRequest        Input   Type of request.  fRequest must
                                contain one of the following
                                values:
                                 ODBC_INSTALL_INQUIRY:  inquire
                                  about where a translator can
                                  be installed
                                 ODBC_INSTALL_COMPLETE:
                                  complete the installation
                                  request

                                translator after this function
                                has been called.

Comments: SQLInstallTranslator provides a mechanism to install just the translator. This function does not actually copy any files. The calling program is responsible for copying the translator files.

If a version of the translator already exists, but the UsageCount value for the translator does not exist, the new UsageCount value is set to 2.

Length of the Path in lpszPathOut: SQLInstallTranslator allows for a two-phase install process, so an application can determine what cbPathOutMax should be by calling SQLInstallTranslator with an fRequest of ODBC_INSTALL_INQUIRY mode. This will return the total number of bytes available in the pcbPathOut buffer. SQLInstallTranslator can then be called with an fRequest of ODBC_INSTALL_COMPLETE and the cbPathOutMax argument set to the value in the pcbPathOut buffer, plus 1.

If you choose not to use the two-phase model for SQLInstallTranslator, then you must set cbPathOutMax to the value _MAX_PATH, as defined in STDLIB.H, to prevent truncation.

When fRequest is ODBC_INSTALL_COMPLETE, SQLInstallTranslator does not allow lpszPathOut to be NULL (or cbPathOutMax to be 0). If fRequest is ODBC_INSTALL_COMPLETE, FALSE is returned when the number of bytes available to return is greater than or equal to cbPathOutMax, with the result that truncation occurs.

        +++++++++++++++SQLRemoveDriver+++++++++++++++

Syntax: BOOL SQLRemoveDriver (lpszDriver, fRemoveDSN, lpdwUsageCount)

Type    Argument        Use     Description

LPCSTR  lpszDriver      Input   The name of the driver as
                                registered in the ODBCINST.INI
                                key of the registry.
BOOL    fRemoveDSN      Input   The valid values are:
                                TRUE  Remove DSNs associated
                                      with the driver specified
                                      in lpszDriver.
                                FALSE Do not remove DSNs
                                      associated with the
                                      driver specified in
                                      lpszDriver.

                                after this function has been
                                called.

Comments: SQLRemoveDriver complements the SQLInstallDriver function, and updates the UsageCount. This function does not actually remove any files. The calling program is responsible for deleting files.

SQLRemoveDriver will decrement the UsageCount value by 1. If the UsageCount goes to 0, then the following will occur:

1. SQLConfigDriver with the ODBC_REMOVE_DRIVER option will be

      +++++++++++++++SQLRemoveDriverManager+++++++++++++++

Syntax: BOOL SQLRemoveDriverManager (lpdwUsageCount)

Type    Argument        Use     Description

                                Manager after this function
                                has been called.

Comments: SQLRemoveDriverManager complements the SQLInstallDriverManager function, and updates the UsageCount. This function does not remove any files. The calling program is responsible for deleting files.

SQLRemoveDriverManager will decrement the UsageCount value of the ODBC core components by 1. If the UsageCount goes to 0, then the ODBC core component registry entry will be removed.

     +++++++++++++++SQLRemoveTranslator+++++++++++++++

Syntax: BOOL SQLRemoveTranslator (lpszTranslator, lpdwUsageCount)

Type    Argument        Use     Description

LPCSTR  lpszTranslator  Input   The name of the translator as
                                registered in the ODBCINST.INI
                                key of the registry.

                                translator after this function
                                has been called.

Comments: If the UsageCount goes to 0, then the translator’s registry entry will be removed. This function does not remove any files. The calling program is responsible for properly removing the translator files.

   +++++++++++++++MODIFIED INSTALLER FUNCTIONS+++++++++++++++

        SQLConfigDataSource
        SQLCreateDataSource
        SQLGetPrivateProfileString
        SQLInstallDriver
        SQLInstallDriverManager
        SQLInstallODBC
        SQLManageDataSources
        SQLWritePrivateProfileString

      +++++++++++++++SQLConfigDataSource+++++++++++++++

Type    Argument        Use     Description

HWND    hwndParent      Input   Parent window handle. The
                                function will not display any
                                dialog boxes if the handle is
                                null.
WORD    fRequest        Input   Type of request. fRequest must
                                contain one of the following
                                values:
                                ODBC_ADD_DSN: Add new user data
                                     source.
                                ODBC_CONFIG_DSN: Modify an
                                     existing data source.
                                ODBC_REMOVE_DSN: Remove an
                                     existing data source.
                                ODBC_ADD_SYS_DSN: Add a new
                                     system data source.
                                ODBC_CONFIG_SYS_DSN: Modify
                                     an existing system data
                                     source.
                                ODBC_REMOVE_SYS_DSN: Remove
                                     an existing system data
                                     source.
LPCSTR  lpszDriver      Input   Driver description (usually the
                                name of the associated DBMS)
                                presented to users instead of
                                the physical driver name.
LPCSTR  lpszAttributes  Input   List of attributes in the form
                                of keyword-value pairs. For
                                more information, see ConfigDSN
                                in the Microsoft ODBC 2.10
                                Programmer's Reference.

SQLConfigDataSource maps the system DSN fRequests to the user DSN fRequests (ODBC_ADD_SYS_DSN to ODBC_ADD_DSN, ODBC_CONFIG_SYS_DSN to ODBC_CONFIG_DSN, and ODBC_REMOVE_SYS_DSN to ODBC_REMOVE_DSN). To distinguish user and system DSNs, SQLConfigDataSource sets the wSystemDSN state variable according to the following table. Prior to returning, SQLConfigDataSource resets wSystemDSN to BOTHDSN.

  fRequest                 wSystemDSN

  ODBC_ADD_DSN             USERDSN_ONLY
  ODBC_CONFIG_DSN          USERDSN_ONLY
  ODBC_REMOVE_DSN          USERDSN_ONLY
  ODBC_ADD_SYS_DSN         SYSTEMDSN_ONLY
  ODBC_CONFIG_SYS_DSN      SYSTEMDSN_ONLY
  ODBC_REMOVE_SYS_DSN      SYSTEMDSN_ONLY

      +++++++++++++++SQLCreateDataSource+++++++++++++++

The System DSN check box is displayed whenever the SQLCreateDataSource function is called to display the Add Data Source dialog box, except when this dialog box is displayed through the Control Panel. In this case, a data source is added either from the Data Sources dialog box (for user data sources) or from the System Data Sources dialog box, so the System DSN check box is not needed.

   +++++++++++++++SQLGetPrivateProfileString+++++++++++++++

       +++++++++++++++SQLInstallDriver+++++++++++++++

    +++++++++++++++SQLInstallDriverManager+++++++++++++++

        +++++++++++++++SQLInstallODBC+++++++++++++++

1. Increment the component usage count of the ODBC core

Note that SQLInstallODBC is the only one of the ODBC installer functions that actually copies files. SQLInstallODBC does not support the Uninstall process. If an application's setup program uses SQLInstallODBC, the application will not be Windows 95 logo compliant.

SQLInstallODBC performs the same functions as SQLInstallDriverManager, SQLInstallDriver, SQLConfigDriver (with ODBC_INSTALL_DRIVER), and SQLInstallTranslator. SQLInstallODBC does not perform the functions accomplished by SQLRemoveTranslator, SQLConfigDriver (with SQL_REMOVE_DRIVER), SQLRemoveDriver, and SQLRemoveDriverManager).

SQLInstallODBC should incorporate the removal functions, and so support Uninstall and Windows 95 logo compliance, in ODBC 3.0.

       +++++++++++++++SQLManageDataSources+++++++++++++++

   +++++++++++++++SQLWritePrivateProfileString+++++++++++++++

                SECTION 3: ODBC FUNCTION CHANGES

The following changes have been made to the ODBC functions documented in the ODBC 2.10 Programmer's Reference and SDK Guide.

    +++++++++++++++REBINDING WITH SQLBindCol+++++++++++++++

+++++++ATTEMPTING TO ADD TRUNCATED DATA WITH SQLSetPos+++++++

Using SQLSetPos with an fOption of SQL_ADD to add data from a buffer that was truncated when bound by a call to SQLBindCol, will result in a General-Protection Fault. Prior to calling SQLSetPos with an fOption of SQL_ADD, application writers should verify that the value pointed to by pcbValue in the accompanying call to SQLBindCol is not greater than cbValueMax.

  +++++++++++++++pcbValue IN SQLBindParameter+++++++++++++++

SQLExecDirect, SQLExecute, and SQLPutData return SQLSTATE 07S01 (Invalid use of default parameter) when a parameter value was set to SQL_DEFAULT_PARAM, and the corresponding parameter was not a parameter for an ODBC canonical procedure invocation.

+++++++++++++SQLSTATE S1C00 RETURNED BY SQLPrepare+++++++++++++

SQLPrepare will return SQLSTATE S1C00 (Driver not capable) if the cursor/concurrency combination is invalid.

+++SQLSTATE 22005 RETURNED BY SQLExtendedFetch and SQLFetch+++

SQLExtendedFetch and SQLFetch will return SQLSTATE 22005 (Error in assignment) if a zero-length string was inserted into a string field, and the field was bound to a numeric data type, so the string was converted to a zero.

+++SQLSTATE 22008 RETURNED BY SQLExtendedFetch and SQLFetch+++

SQLExtendedFetch and SQLFetch will return SQLSTATE 22008 (Datetime field overflow) if a SQL_C_TIME, SQL_C_DATE, or SQL_C_TIMESTAMP value was converted to a SQL_CHAR data type, and the value was, respectively, an invalid date, time, or timestamp.

++++++++++++SQLSTATE 22012 RETURNED BY SQLGetData++++++++++++

SQLGetData will return SQLSTATE 22012 (Division by zero) if a value from an arithmetic expression was returned that resulted in division by zero.

+++++++++++CURSOR CONCURRENCY SET IN SQLSetStmtOption++++++++++

The default value for SQL_CONCURRENCY is SQL_CONCUR_READ_ONLY. This option can also be set through the fConcurrency argument in SQLSetScrollOptions. This option cannot be specified for an open cursor.

If the SQL_CURSOR_TYPE fOption is changed to a type that does not support the current value of SQL_CONCURRENCY, the value of SQL_CONCURRENCY is not automatically changed to a supported value, and no error will be reported until SQLExecDirect or SQLPrepare is called.

If the driver supports the SELECT_FOR_UPDATE statement, and such a statement is executed while the value of SQL_CONCURRENCY is set to SQL_CONCUR_READ_ONLY, an error will be returned. If the value of SQL_CONCURRENCY is changed to a value that the driver supports for some value of SQL_CURSOR_TYPE, but not for the current value of SQL_CURSOR_TYPE, the value of SQL_CURSOR_TYPE is not automatically changed to a supported value, and no error will be reported until SQLExecDirect or SQLPrepare is called.

     ++++++++++++++ERROR MESSAGE FORMAT+++++++++++++

   ++++++++++++++NOTES TO DRIVER WRITERS+++++++++++++