dataprocess.dpr

程序採用了无状态连接池的三层结构

library Dataprocess;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  Sharemem,
  SysUtils,
  Sconnect,
  Variants,
  DBclient,
  DB,
  Forms,
  Classes;

{$R *.res}

type
  TDataprocessc = Class
  public
    function applyupdata(Sct:Tsocketconnection;CDS:TClientdataset; const ptablename,
      pkeyfield: WideString): WordBool; virtual;abstract;
    function getmaxid(Sct:Tsocketconnection;const ptablename, pkeyfield: WideString): Integer;
      Virtual;abstract;
    function Getsqldata(SCT:tsocketconnection;CDS:Tclientdataset;Tablename,
        keyfield:widestring;ssql:string;const MaxRec:integer=20):boolean;
        virtual;abstract;
    function Geteditdata(SCT:tsocketconnection;CDS:Tclientdataset;Tablename,
        keyfield:widestring;Cid:integer;const MaxRec:integer=20):boolean;
        virtual;abstract;
    function Getadddata(SCT:tsocketconnection;CDS:Tclientdataset;Tablename,
        keyfield:widestring;const MaxRec:integer=20):boolean;
        virtual;abstract;
    function GetAllData(SCT:Tsocketconnection;CDS:Tclientdataset;Tablename,
        Keyfield:wideString;const MaxRec:integer=20):boolean;
        virtual;abstract;
    function GetDataFormServer(SCT:Tsocketconnection;ACDS:Tclientdataset;
        sSql:String;const RecCount:integer=20):wordbool;
        virtual;abstract;
    function insertCDSdata(s,d:Tclientdataset):boolean;virtual;abstract;
    function ClearCDSdata(s:Tclientdataset):boolean;virtual;abstract;
end;

type
TDataprocess = class(TDataprocessc)
public
    function applyupdata(Sct:Tsocketconnection;CDS:TClientdataset; const ptablename,
      pkeyfield: WideString): WordBool; override;
    function getmaxid(Sct:Tsocketconnection;const ptablename, pkeyfield: WideString): Integer;
        override;
    function Getsqldata(SCT:tsocketconnection;CDS:Tclientdataset;Tablename,
        keyfield:widestring;ssql:string;const MaxRec:integer=20):boolean;
        override;
    function Geteditdata(SCT:tsocketconnection;CDS:Tclientdataset;Tablename,
        keyfield:widestring;Cid:integer;const MaxRec:integer=20):boolean;
        override;
    function Getadddata(SCT:tsocketconnection;CDS:Tclientdataset;Tablename,
        keyfield:widestring;const MaxRec:integer=20):boolean;
        override;
    function GetAllData(SCT:Tsocketconnection;CDS:Tclientdataset;Tablename,
        Keyfield:wideString;const MaxRec:integer=20):boolean;
        override;
    function GetDataFormServer(SCT:Tsocketconnection;ACDS:Tclientdataset;
        sSql:String;const RecCount:integer=20):wordbool;
        override;
    function insertCDSdata(s,d:Tclientdataset):boolean;override;
    function ClearCDSdata(s:Tclientdataset):boolean;override;
end;

{ TDataprocess }

function TDataprocess.applyupdata(Sct: Tsocketconnection;
  CDS:TClientdataset; const ptablename, pkeyfield: WideString): WordBool;
begin
  Result:=sct.AppServer.applyupdata(CDS.delta,ptablename,pkeyfield);
end;

function TDataprocess.ClearCDSdata(s: Tclientdataset): boolean;
begin
  S.Close;
  S.Data:=Null;
  Result:=True;
end;

function TDataprocess.Getadddata(SCT: tsocketconnection;
  CDS: Tclientdataset; Tablename, keyfield: widestring;
  const MaxRec: integer): boolean;
var
  TmpCDS:Tclientdataset;
  FkeyValue:string;
  Fsql:string;

        function setsqladd():String;
          const
            sqlfmt='Select * from %s%s%s order by %s';
          var
            sid,eid:integer;
          begin
            eid:=Getmaxid(SCT,Tablename,keyField);
            sid:=eid-20;
            if FkeyValue='' then
              begin
                Result:=Format(sqlFmt,[Tablename,' Where ',keyfield+'>='+inttostr(sid)+
                               ' and '+keyfield+'<='+inttostr(eid),keyfield])
              end
              else
              begin
                Result:=Format(sqlFmt,[Tablename,' where ',keyfield+'>'+inttostr(sid)+
                               ' and '+keyfield+'<='+inttostr(eid)+' and '+keyfield+'>'
                               +#39+FkeyValue+#39,keyfield]);
              end;
          end;
begin
  ClearCDSdata(CDS);
  try
  TmpCDS:=Tclientdataset.Create(nil);
  TmpCDS.FetchOnDemand:=False;
  TmpCDS.PacketRecords:=MaxRec;
  Fkeyvalue:='';
  while true do
    begin
      Fsql:=setsqladd();
      if GetDataFormServer(SCT,TmpCDS,Fsql,MaxRec) then
        InsertCDSdata(TmpCDS,CDS);

      if tmpCDS.RecordCount<MaxRec then
        Break;

      TmpCDS.Last;
      FkeyValue:=TmpCDS.fieldbyname(Keyfield).AsString;
      ClearCDSData(TmpCDS);
      Fsql:='';

      Application.ProcessMessages;
    end;
  finally
    TmpCDS.Close;
    TmpCDS.Free; 
  end;
  Result:=True;
end;

function TDataprocess.GetAllData(SCT: Tsocketconnection;
  CDS: Tclientdataset; Tablename, Keyfield: wideString;
  const MaxRec: integer): boolean;
var
TEMPCDS:Tclientdataset;
FkeyValue:String;
Fsql:String;

    function setSqlall():string;
    const
      conFMT = ' select * from   %s%s%s  order  by  %s  ';
    begin
      if FkeyValue='' then
         Result:=Format(conFMT, [Tablename,'','',KeyField])
      else
         Result:=Format(conFMT, [Tablename,' Where ',keyField+'>'+#39+
                        FkeyValue+#39,KeyField]);
    end;

begin
Result:=True;
ClearCDSData(CDS);
try
  TEMPCDS:=Tclientdataset.Create(nil);
  TEMPCDS.FetchOnDemand:=False;
  TEMPCDS.PacketRecords:=MaxRec;
  FkeyValue:='';
  while True do
    begin
      Fsql:=setSqlall;
      GetDataFormServer(SCT,TempCDS,Fsql,MaxRec);
      InsertCDSData(TempCDS,CDS);

      if TEMPCDS.RecordCount<MaxRec then
        Break;

      TEMPCDS.Last;
      FkeyValue:=TEMPCDS.fieldbyname(KeyField).AsString;
      ClearCDSData(TempCDS);
      Fsql:='';

      Application.ProcessMessages;
    end;
finally
  TempCDS.Close;
  TempCDS.Free;
end;
Result:=True;
end;

function TDataprocess.GetDataFormServer(SCT: Tsocketconnection;
  ACDS: Tclientdataset; sSql: String; const RecCount: integer): wordbool;
begin
  Try
    ACDS.Data:=Sct.AppServer.GetlargeData(sSql,RecCount);
    Result:=True;
  Except
    Result:=False;
  end;
end;

function TDataprocess.Geteditdata(SCT: tsocketconnection;
  CDS: Tclientdataset; Tablename, keyfield: widestring; Cid: integer;
  const MaxRec: integer): boolean;
var
  TempCDS:Tclientdataset;
  FkeyValue:string;
  Fsql:String;

    Function setSqledit():string;
      const
        sqlFmt=' Select * from %s%s%s order by %s ';
      var
        sid,eid:integer;
      begin
        sid:=cid-10;
        eid:=Cid+10;
        if FkeyValue='' then
          begin
            Result:=Format(sqlFmt,[Tablename,' where ',keyfield+'>='+inttostr(sid)+
                              ' and '+keyfield+'<='+inttostr(eid),keyfield]);
          end
          else
            Result:=Format(sqlFmt,[Tablename,' where ',keyfield+'>'+inttostr(sid)+
                              ' and '+keyfield+'<='+inttostr(eid)+' and '+
                              keyfield+'>'+#39+FkeyValue+#39,keyfield]);
          end;

begin
  ClearCDSData(Cds);
  try
    TempCDS:=Tclientdataset.Create(nil);
    TempCDS.FetchOnDemand:=False;
    TempCDS.PacketRecords:=MaxRec;
    FkeyValue:='';
    While True do
      begin
        Fsql:=setSqledit;
        GetDataFormServer(SCT,TempCDS,Fsql,MaxRec);
        InsertCDSdata(TempCDS,CDS);

        if TempCDS.RecordCount<MaxRec then
          Break;

        TempCDS.Last;
        FkeyValue:=TempCDS.fieldbyname(Keyfield).AsString;
        ClearCDSData(TempCDS);
        Fsql:='';

        Application.ProcessMessages;
      end;
  finally
    TempCDS.Close;
    TempCds.Free();
  end;
  Result:=True;
end;

function TDataprocess.getmaxid(Sct: Tsocketconnection; const ptablename,
  pkeyfield: WideString): Integer;
begin
  try
    Result:=Sct.AppServer.Getmaxid(ptablename,pkeyfield);
  except
    Result:=0;
  end;
end;

function TDataprocess.Getsqldata(SCT: tsocketconnection;
  CDS: Tclientdataset; Tablename, keyfield: widestring; ssql: string;
  const MaxRec: integer): boolean;
var
  TempCDS:Tclientdataset;
  FkeyValue:string;
  Fsql:String;

    Function setSqlsql():string;
      const
        sqlFmt=' Select * from %s%s%s order by %s ';
      begin
        if FkeyValue='' then
          begin
            Result:=Format(sqlFmt,[Tablename,' where ',ssql,keyField]);
          end
          else
            Result:=Format(sqlFmt,[Tablename,' where ',
                     keyField+'>'+#39+FkeyValue+#39+' and '+ssql,keyField]);
          end;

begin
  ClearCDSData(Cds);
  try
    TempCDS:=Tclientdataset.Create(nil);
    TempCDS.FetchOnDemand:=False;
    TempCDS.PacketRecords:=MaxRec;
    FkeyValue:='';
    While True do
      begin
        Fsql:=setSqlsql;
        GetDataFormServer(SCT,TempCDS,Fsql,MaxRec);
        InsertCDSdata(TempCDS,CDS);

        if TempCDS.RecordCount<MaxRec then
          Break;

        TempCDS.Last;
        FkeyValue:=TempCDS.fieldbyname(Keyfield).AsString;
        ClearCDSData(TempCDS);
        Fsql:='';

        Application.ProcessMessages;
      end;
  finally
    TempCDS.Close;
    TempCds.Free();
  end;
  Result:=True;
end;

function TDataprocess.insertCDSdata(s, d: Tclientdataset): boolean;
var
  V:Tbookmark;
begin
  Result:=true;
  try
    V:=D.GetBookmark;
      if D.Active then
        d.AppendData(S.Data,False)
      else
        D.Data:=S.Data;
  Finally
    D.GotoBookmark(V);
    D.FreeBookmark(V);
  end;
end;

function CreateDataprocess:TDataprocess;stdcall;
begin
  Result:=Tdataprocess.Create;
end;

Exports
  CreateDataprocess;

begin
end.