ODBC - Open DataBase Connectivity Basic Steps Connecting to the SQL Server DataBase for retrieving information from tables     '*************************************************************************** 'The steps 1 - 3 are for connecting to the SQL Server Database '***************************************************************************   1. Allocate ODBC Environment Handle If SQLAllocEnv(glEnv) <> 0 Then MsgBox "Unable to initialize ODBC API drivers!" End End If   2. Allocate ODBC Database Handle Dim iStatus As Integer   If SQLAllocConnect(glEnv, glDbc) <> 0 Then MsgBox "Could not allocate memory for connection Handle!" ODBCInit = False ' Free the Environment iStatus = SQLFreeEnv(lEnv) If iStatus = SQL_ERROR Then MsgBox "Error Freeing Environment From ODBC Drivers" End If   ' Quit the Application End End If       3. Connect using the sConnect string - SQLDriverConnect Dim sResult As String Dim iSize As Integer Dim sConnect As String sConnect = "DSN=" & gsDSN & ";UID=" & gsLoginID & ";PWD=" & gsPassword & ";APP=" sConnect = sConnect & gsAppCode & ";DATABASE=" & gsDatabase   If SQLDriverConnect(glDbc, Screen.ActiveForm.hWnd, sConnect, Len(sConnect), _ sResult, Len(sResult), iSize, 0) <= 0 Then MsgBox "Could not establish connection to ODBC driver!" End If   '*********************************************************** 'The steps 4 - 8 are for retrieving data from tables '***********************************************************   4. Allocate ODBC Statement Handle If SQLAllocStmt(glDbc, glStmt) <> 0 Then MsgBox "Could not allocate memory for a statement handle!" End If   5. Execute ODBC Statement - SQLExecDirect Dim lRet As Long, lErrNo As Long Dim iLen As Integer Dim sSQLState As String * MAX_DATA_BUFFER Dim sErrorMsg As String * MAX_DATA_BUFFER Dim sMsg As String   sSQL = "SELECT name, location FROM authors" If SQLExecDirect(glStmt, sSQL, Len(sSQL)) <> SQL_SUCCESS Then 'Also Check for ODBC Error message - SQLError lRet = SQLError(glEnv, gldbc, glStmt, sSQLState, lErrNo, sErrorMsg, MAX_DATA_BUFFER, iLen) sMsg = "Error Executing SQL Statement" & Chr$(13) & Chr$(10) sMsg = sMsg & "ODBC State = " & Trim$(Left$(sSQLState, InStr(sSQLState, Chr$(0)) - 1)) & Chr$(13) & Chr$(10) sMsg = sMsg & "ODBC Error Message = " & Left$(sErrorMsg, iLen) MsgBox sMsg, vbInformation, "Execute Query" End If     6. Fetch one row of results from executed ODBC Statement - SQLFetch Code in Step 7.   7. Get the Data in each field of the Fetched row - SQLGetData Dim bPerform As Integer, iStatus As Integer Dim sData As String * MAX_DATA_BUFFER Dim lOutLen As Long   bPerform = SQLFetch(glStmt)   Do While bPerform bPerform = SQLFetch(lStmt) ' Get the next row of data If bPerform = SQL_SUCCESS Then ' If rows of data available bPerform = True ' Get Author Name - iColumn = 1 for first field i.e. name in sSQL iStatus = SQLGetData(glStmt, iColumn, 1, sData, MAX_DATA_BUFFER, lOutLen) ' lOutlen = length of the valid data in sData ' Data value will be = Left$(sData, lOutlen), lOutlen = -1 if no data or Null data   ' Get Location - iColumn = 2 for second field i.e. location in sSQL iStatus = SQLGetData(glStmt, iColumn, 1, sData, MAX_DATA_BUFFER, lOutLen)   ' Add the Field Data to Correponding Data Display Controls for this row Else bPerform = False ' No more rows available End If Loop   'Release the ODBC Statement Handle bPerform = SQLFreeStmt(glStmt, SQL_DROP)   8. Release the ODBC Statement Handle - SQLFreeSTmt Code in Step 7.     '*********************************************************************** 'The steps 9 - 11 are for Disconnecting from the SQL Server DataBase '***********************************************************************   9. Disconnect from ODBC Database - SQLDisconnect iStatus = SQLDisconnect(glDbc)   10. Release the ODBC Database Handle - SQLFreeConnect iStatus = SQLFreeConnect(glDbc)   11. Release the ODBC Environment Handle - SQLFreeEnv iStatus = SQLFreeEnv(glEnv)   '*********************************************************************** 'The following entries are required in the ODBCAPI module '*********************************************************************** ' ODBC Variables and Constants   Global glEnv As Long Global glDbc As Long Global sSQL As String   Global Const MAX_DATA_BUFFER = 255 Global Const SQL_SUCCESS = 0 Global Const SQL_SUCCESS_WITH_INFO = 1 Global Const SQL_ERROR = -1 Global Const SQL_NO_DATA_FOUND = 100 Global Const SQL_CLOSE = 0 Global Const SQL_DROP = 1 Global Const SQL_CHAR = 1 Global Const SQL_NUMERIC = 2 Global Const SQL_DECIMAL = 3 Global Const SQL_INTEGER = 4 Global Const SQL_SMALLINT = 5 Global Const SQL_FLOAT = 6 Global Const SQL_REAL = 7 Global Const SQL_DOUBLE = 8 Global Const SQL_VARCHAR = 12 Global Const SQL_DATA_SOURCE_NAME = 6 Global Const SQL_USER_NAME = 8 NOTE : The constants above have been put in a tablular format to save space.   'ODBC Declarations ' The hWnd is a Long in Windows 95 & Windows NT #If Win32 Then Declare Function SQLAllocEnv Lib "odbc32.dll" (env As Long) As Integer Declare Function SQLFreeEnv Lib "odbc32.dll" (ByVal env As Long) As Integer Declare Function SQLAllocConnect Lib "odbc32.dll" (ByVal env As Long, ldbc As Long) As Integer Declare Function SQLConnect Lib "odbc32.dll" (ByVal ldbc As Long, ByVal Server As String, _ ByVal serverlen As Integer, ByVal uid As String, ByVal uidlen As Integer, _ ByVal pwd As String, ByVal pwdlen As Integer) As Integer Declare Function SQLDriverConnect Lib "odbc32.dll" (ByVal ldbc As Long, ByVal hWnd As Long, _ ByVal szCSIn As String, ByVal cbCSIn As Integer, ByVal szCSOut As String, _ ByVal cbCSMax As Integer, cbCSOut As Integer, ByVal f As Integer) As Integer Declare Function SQLFreeConnect Lib "odbc32.dll" (ByVal ldbc As Long) As Integer Declare Function SQLDisconnect Lib "odbc32.dll" (ByVal ldbc As Long) As Integer Declare Function SQLAllocStmt Lib "odbc32.dll" (ByVal ldbc As Long, lStmt As Long) As Integer Declare Function SQLFreeStmt Lib "odbc32.dll" (ByVal lStmt As Long, ByVal EndOption As Integer) As Integer Declare Function SQLTables Lib "odbc32.dll" (ByVal lStmt As Long, ByVal q As Long, _ ByVal cbq As Integer, ByVal o As Long, ByVal cbo As Integer, ByVal t As Long, _ ByVal cbt As Integer, ByVal tt As Long, ByVal cbtt As Integer) As Integer Declare Function SQLExecDirect Lib "odbc32.dll" (ByVal lStmt As Long, ByVal sqlString As String, _ ByVal sqlstrlen As Long) As Integer Declare Function SQLNumResultCols Lib "odbc32.dll" (ByVal lStmt As Long, NumCols As Integer) As Integer Declare Function SQLDescribeCol Lib "odbc32.dll" (ByVal lStmt As Long, ByVal colnum As Integer, _ ByVal colname As String, ByVal Buflen As Integer, colnamelen As Integer, dtype As Integer, _ dl As Long, ds As Integer, n As Integer) As Integer Declare Function SQLFetch Lib "odbc32.dll" (ByVal lStmt As Long) As Integer Declare Function SQLGetData Lib "odbc32.dll" (ByVal lStmt As Long, ByVal col As Integer, _ ByVal wConvType As Integer, ByVal lpbBuf As String, ByVal dwbuflen As Long, _ lpcbout As Long) As Integer Declare Function SQLGetInfo Lib "odbc32.dll" (ByVal ldbc As Long, ByVal hWnd As Long, _ ByVal szInfo As String, ByVal cbInfoMax As Integer, cbInfoOut As Integer) As Integer Declare Function SQLError Lib "odbc32.dll" (ByVal env As Long, ByVal ldbc As Long, ByVal lStmt As Long, _ ByVal SQLState As String, NativeError As Long, ByVal Buffer As String, ByVal Buflen As Integer, _ Outlen As Integer) As Integer     #Else Declare Function SQLAllocEnv Lib "odbc.dll" (env As Long) As Integer Declare Function SQLFreeEnv Lib "odbc.dll" (ByVal env As Long) As Integer Declare Function SQLAllocConnect Lib "odbc.dll" (ByVal env As Long, ldbc As Long) As Integer Declare Function SQLConnect Lib "odbc.dll" (ByVal ldbc As Long, ByVal Server As String, _ ByVal serverlen As Integer, ByVal uid As String, ByVal uidlen As Integer, _ ByVal pwd As String, ByVal pwdlen As Integer) As Integer Declare Function SQLDriverConnect Lib "odbc.dll" (ByVal ldbc As Long, ByVal hWnd As Integer, _ ByVal szCSIn As String, ByVal cbCSIn As Integer, ByVal szCSOut As String, _ ByVal cbCSMax As Integer, cbCSOut As Integer, ByVal f As Integer) As Integer Declare Function SQLFreeConnect Lib "odbc.dll" (ByVal ldbc As Long) As Integer Declare Function SQLDisconnect Lib "odbc.dll" (ByVal ldbc As Long) As Integer Declare Function SQLAllocStmt Lib "odbc.dll" (ByVal ldbc As Long, lStmt As Long) As Integer Declare Function SQLFreeStmt Lib "odbc.dll" (ByVal lStmt As Long, _ ByVal EndOption As Integer) As Integer Declare Function SQLTables Lib "odbc.dll" (ByVal lStmt As Long, ByVal q As Long, _ ByVal cbq As Integer, ByVal o As Long, ByVal cbo As Integer, ByVal t As Long, _ ByVal cbt As Integer, ByVal tt As Long, ByVal cbtt As Integer) As Integer Declare Function SQLExecDirect Lib "odbc.dll" (ByVal lStmt As Long, ByVal sqlString As String, _ ByVal sqlstrlen As Long) As Integer Declare Function SQLNumResultCols Lib "odbc.dll" (ByVal lStmt As Long, NumCols As Integer) As Integer Declare Function SQLDescribeCol Lib "odbc.dll" (ByVal lStmt As Long, ByVal colnum As Integer, _ ByVal colname As String, ByVal Buflen As Integer, colnamelen As Integer, dtype As Integer, _ dl As Long, ds As Integer, n As Integer) As Integer Declare Function SQLFetch Lib "odbc.dll" (ByVal lStmt As Long) As Integer Declare Function SQLGetData Lib "odbc.dll" (ByVal lStmt As Long, ByVal col As Integer, _ ByVal wConvType As Integer, ByVal lpbBuf As String, ByVal dwbuflen As Long, _ lpcbout As Long) As Integer Declare Function SQLGetInfo Lib "odbc.dll" (ByVal ldbc As Long, ByVal hWnd As Integer, _ ByVal szInfo As String, ByVal cbInfoMax As Integer, cbInfoOut As Integer) As Integer Declare Function SQLError Lib "odbc.dll" (ByVal env As Long, ByVal ldbc As Long, _ ByVal lStmt As Long, ByVal SQLState As String, NativeError As Long, _ ByVal Buffer As String, ByVal Buflen As Integer, Outlen As Integer) As Integer #End If     ODBC BASIC STEPS Page 1   Compiled by Uddip Mitra (email: uddip@jersey-city.crosswinds.net) Downloads In IE right-click and select 'Save Target As...' or in Netscape right-click and select 'Save Link As...'    View Plain Text  Download Demo Project  Not Available