api4.dpr

jvcl driver development envionment

(*
 *  Program type:  API Interface
 *
 *  Desription:
 *      This program updates departments' budgets, given
 *      the department and the new budget information parameters.
 *
 *      An input SQLDA is allocated for the update query
 *      with parameter markers.
 *      Note that all updates are rolled back in this version.
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at:
 * http://www.borland.com/devsupport/interbase/opensource/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Borland Software Corporation
 * and its predecessors.  Portions created by Borland are Copyright (c)
 * 1994 - 2001 Borland Software Corporation.
 * All rights reserved.
 *
 * Contributor(s):
 *                 Aaron Ruddick InterBase QA, Borland Software Corp.
 *                 Dan Mikhayltsa  InterBase QA, Borland Software Corp.
 *)

program api4;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  JvUIBase,
  JvUIBLib;

var
  Dept_data    : array[0..4] of string = ('622', '100', '116', '900', '');
  Percent_data : array[0..4] of Double = (0.05,  1.00,  0.075,  0.10, 0);
  Input_ptr : Integer = 0;
  updstr: string = 'UPDATE department SET budget = ? * budget + budget WHERE dept_no = ?';

  DB   : IscDbHandle = nil; // database handle
  trans: IscTrHandle = nil; // transaction handle


  dept_no : string;
  percent_inc: Double;
  flag0 : Smallint = 0;
  flag1 : Smallint = 0;
  sqlda : TSQLParams;
  empdb : String;
  FLibrary: TUIBLibrary;

(*
 *  Get the department and percent parameters.
 *)

function get_input (out dept_no: string; out percent: double): boolean;
begin
  Result := False;
  if (Dept_data[Input_ptr] = '') then  Exit;
  dept_no := Dept_data[Input_ptr];
  inc(Input_ptr);
  percent := Percent_data[Input_ptr];
  Result := true;
end;



begin
  FLibrary := TUIBLibrary.Create;
  try

  if (ParamCount > 1) then
    empdb := ParamStr(1) else
    empdb := 'D:\Unified Interbase\demo\Database\employee.db';

  FLibrary.AttachDatabase(empdb, DB, 'user_name=SYSDBA;password=masterkey');

  (* Allocate an input SQLDA.  There are two unknown parameters. *)
  sqlda := TSQLParams.Create;
  try
    sqlda.AddFieldType('0', uftFloat);
    sqlda.AddFieldType('1',uftVarchar);
//!!!    sqlda.AddDouble; // percent_inc
//!!!    sqlda.AddString; // dept_no

    (*
     *  Get the next department-percent increase input pair.
     *)
    while get_input(dept_no, percent_inc) do
    begin
      sqlda.AsDouble[0] := percent_inc;
      sqlda.AsString[1] := dept_no;
      Writeln(Format('Increasing budget for department:  %s  by %5.2f percent.',[dept_no, percent_inc]));
      FLibrary.TransactionStart(trans, DB);

      (* Update the budget. *)
      try
        FLibrary.DSQLExecuteImmediate(DB, trans, updstr, 1, sqlda);
      except
        on E: EUIBError do
        begin
          if (E.SqlCode <> 0) then
          begin
            (* Don't save the update, if the new budget exceeds the limit. *)
            if (E.sqlcode = -625) then
            begin
              writeln('Exceeded budget limit -- not updated.');
              FLibrary.TransactionRollback(trans);
              continue;
            end;
            (* Undo all changes, in case of an error. *)
          end else
          begin
            FLibrary.TransactionRollback(trans);
            raise;
          end;
        end;
      end;

      (* Save each department's update independently.
      ** Change to CommitTransaction to see changes
       *)
      FLibrary.TransactionRollback(trans);
    end;

    FLibrary.DetachDatabase(DB);
  finally
    sqlda.Free;
  end;
  Readln;
  finally
    FLibrary.Free;
  end;
end.