TeslaRel410/BORLAND/BDE/EXAMPLES/PASCAL/LSQLLIVE.PAS

{ lsqllive.pas }
program LSqlLive;

{$IfDef VER80}
uses SnipTool, SnipData, SysUtils, WinTypes, WinProcs,
     DbiProcs, DbiTypes, DbiErrs;
{$Else}
uses WinTypes, WinCrt, Strings, DbiProcs, DbiTypes, DbiErrs,
     SnipTool, SnipData;
{$EndIf}

const
    szTblName = 'cust';  { Name of table to be created. }
    szTblType = szDBASE; { Table type to use. }

{=====================================================================
   Function:
           LiveSQL();

   Description:
           This example shows how to do live local SQL on a dBASE table.
 ===================================================================== }

var
    hDb: hDBIDb;          { Handle to the Database }
    hCur: hDBICur;        { Handle to the Answer Table }
    hStmt: hDBIStmt;      { Handle to the SQL Statement }
    hMCur: hDBICur;       { Handle to the master table. }
    uLength: UINT16;
    TblProps: CURProps;   { Table descriptor }
    TblMProps: CURProps;  { Table descriptor }
    bEmpty: BOOL;
    szCity: array[0..20] of CHAR;
    bLive: LIVENESS;
    ulCustNum: FLOAT;

const
    szQry = 'SELECT cust_no, name, city, phone, country '#13+
            'FROM "cust.dbf" '#13+
            'WHERE cust_no>4000'; { The Text of the SQL Statement }
    pRecBuf: pBYTE = nil;         { Pointer to the record buffer }
    pMRecBuf: pBYTE = nil;        { Pointer to the record buffer }
    szNewCity: pCHAR = 'Chicago';

begin
    Screen('*** Live Answer Table Example ***');

    Screen('    Initializing IDAPI...');
    if (InitAndConnect(hDb) <> DBIERR_NONE) then { Terminate example if }
    begin                                        { Initialization fails }
        Screen('');
        Screen('*** End of Example ***');
        exit;
    end;

    Screen('    Setting the default Database directory...');
    ChkRslt(DbiSetDirectory(hDb, pCHAR(szTblDirectory)), DBIERR_NONE,
            '    Error - SetDirectory.');

    Screen('    Perform the following SQL statement on the table:');
    Screen('');
    Screen(szQry);

    Screen('');
    Screen('    Prepare the SQL statement...');
    if (ChkRslt(DbiQPrepare(hDb, qrylangSQL, szQry, hStmt),
                   DBIERR_NONE, '        Error - QPrepare.')
        <> DBIERR_NONE) then
    begin
        CloseDbAndExit(hDb);
        Screen('');
        Screen('*** End of Example ***');
        exit;
    end;

    { Determine the state of the answer set - is it live or not. }
    ChkRslt(DbiGetProp (hDBIObj(hStmt), stmtLIVENESS, @(bLive),
                       sizeof(BOOL), uLength), DBIERR_NONE,
            '    Error - GetProp.');

    { Check if the statement cursor is live. }
    if (bLive <> wantLIVE) then
    begin
        { Now set the statement cursor to be live. }
        ChkRslt(DbiSetProp(hDBIObj(hStmt), stmtLIVENESS, LongInt(wantLIVE)),
                DBIERR_NONE, '    Error - SetProp.');
    end;

    Screen('    Execute the SQL statement...');
    if (ChkRslt(DbiQExec(hStmt, @hCur), DBIERR_NONE, '    Error - QExec.')
                <> DBIERR_NONE) then
    begin
        CloseDbAndExit(hDb);
        Screen('');
        Screen('*** End of Example ***');
        exit;
    end;

    { Determine if a valid hCursor was returned. }
    if Assigned (hCur) then
    begin
        Screen('    Opening the master table....');
        if (ChkRslt(DbiOpenTable(hDb, pCHAR(szTblName), pCHAR(szTblType),
                         nil, nil, 0, dbiREADWRITE, dbiOPENSHARED,
                         xltFIELD, FALSE, nil, hMCur),
                    DBIERR_NONE, '    Error - OpenTable.') <> DBIERR_NONE) then
        begin
            ChkRslt(DbiCloseCursor(hCur), DBIERR_NONE,
                    '    Error - CloseCursor.');
            CloseDbAndExit(hDb);
            Screen('');
            Screen('*** End of Example ***');
            exit;
        end;

        { Next allocate memory for the record buffer. }
        ChkRslt(DbiGetCursorProps(hMCur, TblMProps), DBIERR_NONE,
                '  Error - GetCursorProps.');

        GetMem(pMRecBuf, TblMProps.iRecBufSize);

        Screen('');
        Screen('    Switching to an index in the master table... ');
        ChkRslt(DbiSwitchToIndex(hMCur, 'CUST.MDX', 'CUST_NO', 0,
                         FALSE), DBIERR_NONE,
                         '    Error - SwitchToIndex.');

        Screen('    Clear the record buffer...');
        ChkRslt(DbiInitRecord(hMCur, pMRecBuf), DBIERR_NONE,
                '    Error - InitRecord.');

        Screen('    Display the first Record in the answer table...');
        ChkRslt(DbiSetToBegin(hCur), DBIERR_NONE, '    Error - SetToBegin.');
        DisplayTable(hCur, 1);

        { Modify the table and then change back to the original values. }
        ChkRslt(DbiGetCursorProps(hCur, TblProps), DBIERR_NONE,
                '  Error - GetCursorProps.');

        { Next allocate memory for the record buffer. }
        GetMem(pRecBuf, TblProps.iRecBufSize);

        { Now get the first record in the live query. }
        ChkRslt(DbiSetToBegin(hCur), DBIERR_NONE, '    Error - SetToBegin.');
        ChkRslt(DbiGetNextRecord(hCur, dbiNOLOCK, pRecBuf, nil),
                DBIERR_NONE, '    Error - GetNextRecord.');

        { Get the Master table's fourth field (which is the 3rd field for
          the answer table) value so that we can put it back after
          modifying the table. }
        ChkRslt(DbiGetField(hCur, 3, pRecBuf, @szCity, bEmpty),
                            DBIERR_NONE, '    Error - GetField.');

        ChkRslt(DbiGetField(hCur, 1, pRecBuf, @(ulCustNum), bEmpty),
                            DBIERR_NONE, '    Error - GetField.');

        { Modify the City of the first record. }
        ChkRslt(DbiPutField(hCur, 3, pRecBuf, szNewCity),
                            DBIERR_NONE, '    Error - PutField.');

        Screen('');
        Screen('    Modifying the City field in the first record '+
               'of the DynaSet from '+StrPas(szCity)+' to ' +
               ''+StrPas(szNewCity)+'....');

        ChkRslt(DbiModifyRecord(hCur, pRecBuf, TRUE), DBIERR_NONE,
                '    Error - ModifyRecord.');

        Screen('    Re-displaying the Modified Record of the master table '+
               'to show the change took place...');

        { Now set the value for the search into the record buffer. }
        ChkRslt(DbiPutField(hMCur, 1, pMRecBuf, @(ulCustNum)),
                            DBIERR_NONE, '    Error - PutField.');

        { Now set the cursor unto the field in the master table - to verify
          that it was modified. }
        ChkRslt(DbiSetToKey(hMCur, keySEARCHEQ, FALSE, 0, 0,
                            pMRecBuf), DBIERR_NONE,
                '    Error - SetToKey');

        DisplayNextRecord(hMCur);

        ChkRslt(DbiSetToBegin(hCur), DBIERR_NONE, '    Error - SetToBegin.');

        { Change the data back to the way it was. }
        ChkRslt(DbiGetNextRecord(hCur, dbiNOLOCK, pRecBuf, nil),
                DBIERR_NONE, '    Error - GetRecord.');

        ChkRslt(DbiPutField(hCur, 3, pRecBuf, @szCity),
                            DBIERR_NONE, '    Error - PutField.');

        Screen('');
        Screen('    Saving back the original City name to keep the ' +
               'example table consistent...');
        ChkRslt(DbiModifyRecord(hCur, pRecBuf, TRUE), DBIERR_NONE,
                '    Error - ModifyRecord.');

        Screen('');
        Screen('    Close the cursor to the answer set...  ');
        ChkRslt(DbiCloseCursor(hCur), DBIERR_NONE,
                '    Error - CloseCursor.');

        Screen('');
        Screen('    Close the cursor to the master table...  ');
        ChkRslt(DbiCloseCursor(hMCur), DBIERR_NONE,
                '    Error - CloseCursor.');

        FreeMem(pRecBuf, TblProps.iRecBufSize);
        FreeMem(pMRecBuf, TblMProps.iRecBufSize);
    end
    else
        Screen('        Could not get cursor to the answer table.');


    Screen('');
    Screen('    Release memory allocated for the Query...');
    ChkRslt(DbiQFree(hStmt), DBIERR_NONE, '        Error - QryFree.');

    Screen('    Close the Database and exit IDAPI...');
    CloseDbAndExit(hDb);

    Screen('*** End of Example ***');

end.