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(*
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* Firebird UDR Support (fbudrtested). The fbudr components provide a set of
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* Pascal language bindings for the Firebird API in support of server
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* side User Defined Routines (UDRs). The fbudr package is an extension
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* to the Firebird Pascal API.
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*
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* The contents of this file are subject to the Initial Developer's
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* Public License Version 1.0 (the "License"); you may not use this
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* file except in compliance with the License. You may obtain a copy
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* of the License here:
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*
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* http://www.firebirdsql.org/index.php?op=doc&id=idpl
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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* implied. See the License for the specific language governing rights
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* and limitations under the License.
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*
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* The Initial Developer of the Original Code is Tony Whyman.
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*
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* The Original Code is (C) 2021 Tony Whyman, MWA Software
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* (http://www.mwasoftware.co.uk).
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*
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* All Rights Reserved.
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*
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* Contributor(s): ______________________________________.
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*
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*)
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unit udr_test03;
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{$IFDEF MSWINDOWS}
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{$DEFINE WINDOWS}
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{$ENDIF}
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{$IFDEF FPC}
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{$mode delphi}
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{$codepage UTF8}
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{$interfaces COM}
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{$ENDIF}
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interface
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uses
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Classes, SysUtils, IB, FBUDRController, FBUDRIntf{$IFDEF FPC}, Streamex{$ENDIF};
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{This unit provides the implementation of selected number of UDR Select
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procedures used to test out various aspects of the TFBUDRSelectProcedure class.
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Note that each class is registered with the FBUDRController at initialization time.}
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type
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{TMySelectProcedure implements a simple select procedure to return the
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list of employee salaries plus a line by line accumulator. The employee
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database is assumed.
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create or alter procedure MySelectProc ()
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returns (FullName VarChar(36), Salary Numeric(10,2), AccSalary Numeric(10,2) )
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external name 'fbudrtests!select_proc'
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engine udr;
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}
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TMySelectProcedure = class(TFBUDRSelectProcedure)
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private
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FAccSalary: currency;
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FResults: IResultset;
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public
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procedure open(context: IFBUDRExternalContext;
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ProcMetadata: IFBUDRProcMetadata;
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InputParams: IFBUDRInputParams); override;
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function fetch(OutputData: IFBUDROutputData): boolean; override;
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procedure close; override;
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end;
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{TReadTextFile is a select procedure that reads lines from a text file and
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returns each line as successive rows.
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create or alter procedure MyReadText (
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path varchar(200) not null /*relative to udr directory */
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) returns (
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text varchar(100) not null
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)
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external name 'fbudrtests!read_txt'
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engine udr;
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}
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TReadTextFile = class(TFBUDRSelectProcedure)
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private
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FTextFile: TStreamReader;
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public
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procedure open(context: IFBUDRExternalContext;
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ProcMetadata: IFBUDRProcMetadata;
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InputParams: IFBUDRInputParams); override;
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function fetch(OutputData: IFBUDROutputData): boolean; override;
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procedure close; override;
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end;
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implementation
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{ TMySelectProcedure }
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{open is called first and opens the cursor. The IResultset returned is saved
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as a private property of the class, and the accumulator is initialized to zero.}
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procedure TMySelectProcedure.open(context: IFBUDRExternalContext;
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ProcMetadata: IFBUDRProcMetadata; InputParams: IFBUDRInputParams);
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begin
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with context do
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FResults := GetAttachment.OpenCursor(GetTransaction,'Select Full_Name,Salary from EMPLOYEE order by EMP_NO');
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FAccSalary := 0;
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end;
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{fetch is called to return each row in the OutputData. The function returns
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false when at EOF.}
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function TMySelectProcedure.fetch(OutputData: IFBUDROutputData): boolean;
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begin
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Result := (FResults <> nil) and FResults.FetchNext;
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if Result then
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begin
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FAccSalary := FAccSalary + FResults.ByName('Salary').AsCurrency;
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OutputData.ByName('FullName').AsString := FResults.ByName('Full_Name').AsString;
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OutputData.ByName('Salary').AsCurrency := FResults.ByName('Salary').AsCurrency;
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OutputData.ByName('AccSalary').AsCurrency := FAccSalary;
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end;
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end;
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{close is called after fetch returned EOF. Here is is used to explicitly close
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the cursor. Although this will be closed automatically when the class is
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freed, or open called again.}
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procedure TMySelectProcedure.close;
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begin
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FResults := nil;
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end;
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procedure TReadTextFile.open(context: IFBUDRExternalContext;
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ProcMetadata: IFBUDRProcMetadata;
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InputParams: IFBUDRInputParams);
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var aFileName: AnsiString;
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{$IFDEF FPC}F: TFileStream;{$ENDIF}
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begin
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context.WriteToLog('Read Text called in directory '+ GetCurrentDir);
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aFileName := InputParams.ByName('path').AsString;
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if not FileExists(aFileName) then
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raise Exception.CreateFmt('Unable to find file "%s"',[aFileName]);
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context.WriteToLog('Reading from ' + aFileName);
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{$IFDEF FPC}
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F := TFileStream.Create(aFileName,fmOpenRead);
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FTextFile := TStreamReader.Create(F,8192,true);
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{$ELSE}
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FTextFile := TStreamReader.Create(aFileName, TEncoding.ANSI);
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{$ENDIF}
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end;
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function TReadTextFile.fetch(OutputData: IFBUDROutputData): boolean;
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begin
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Result := not FTextFile.{$IFDEF FPC}EOF{$ELSE}EndOfStream{$ENDIF};
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if Result then
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OutputData.ByName('text').AsString := FTextFile.ReadLine;
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end;
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procedure TReadTextFile.close;
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begin
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if FTextFile <> nil then
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FTextFile.Free;
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FTextFile := nil;
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end;
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Initialization
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FBRegisterUDRProcedure('select_proc',TMySelectProcedure);
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FBRegisterUDRProcedure('read_txt',TReadTextFile);
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end.
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