child_borrow.pas

一个桌面数据库应用的源码,适合初学数据库编程的新手.

unit Child_Borrow;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Mask, DBCtrls, ComCtrls, Db, DBTables, ExtCtrls, Grids,
  DBGrids, Buttons;

type
  Tfrm_Borrow = class(TForm)
    Panel1: TPanel;
    DBNavigator: TDBNavigator;
    DataSource1: TDataSource;
    Query1: TQuery;
    DataSource2: TDataSource;
    Table2: TTable;
    Table1: TTable;
    Panel3: TPanel;
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    Label8: TLabel;
    Label7: TLabel;
    Label6: TLabel;
    Label5: TLabel;
    Label2: TLabel;
    Label1: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label9: TLabel;
    EditDBEdit8: TDBEdit;
    EditDBEdit5: TDBEdit;
    EditDBEdit6: TDBEdit;
    EditDBEdit7: TDBEdit;
    EditDBEdit: TDBEdit;
    EditDBEdit2: TDBEdit;
    EditDBEdit3: TDBEdit;
    EditDBEdit4: TDBEdit;
    DBEdit1: TDBEdit;
    TabSheet2: TTabSheet;
    Panel2: TPanel;
    Label22: TLabel;
    Label21: TLabel;
    Label20: TLabel;
    Label23: TLabel;
    SpeedButton1: TSpeedButton;
    SpeedButton2: TSpeedButton;
    Edit_No: TEdit;
    Edit_name: TEdit;
    Edit_DateIn: TEdit;
    RadioGroup1: TRadioGroup;
    Edit_DateOut: TEdit;
    DBGrid1: TDBGrid;
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure PageControl1Change(Sender: TObject);
    procedure SpeedButton1Click(Sender: TObject);
    procedure DataSource1DataChange(Sender: TObject; Field: TField);
    procedure FormActivate(Sender: TObject);
  private
    procedure AllRec;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frm_Borrow: Tfrm_Borrow;

implementation

uses Main;

{$R *.DFM}

procedure Tfrm_Borrow.AllRec;
begin
  with Query1 do
  begin
    SQL.Clear;
    SQL.Add('SELECT * FROM "Borrow.db"');
    Prepare;
    ExecSQL;
    Open;
  end;
end;

procedure Tfrm_Borrow.FormCreate(Sender: TObject);
begin
  Height:=Constraints.MinHeight;
  Width:=Constraints.MinWidth;
  Panel1.Align:=alTop;
  Panel3.Align:=alClient;  
  PageControl1.Align:=alClient;
  PageControl1.ActivePageIndex:=0;
  DBGrid1.Align:=alClient;
  Table1.DatabaseName:=MainForm.GetExePath+'mdb';
  Table1.TableName:='Borrow.DB';
  Table2.DatabaseName:=MainForm.GetExePath+'mdb';
  Table2.TableName:='Lab.DB';
  Query1.DatabaseName:=MainForm.GetExePath+'mdb';
  table1.Open;
  table2.Open;
end;

procedure Tfrm_Borrow.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  table1.Close;
  table2.Close;
  Query1.Close;
  with Mainform do
  begin
//    StatusBar.Panels[1].Text:='仪器借用库已关闭';
    if MDIChildCount=1 then
      StatusBar.Panels[1].Text:='';
  end;
  Action:=caFree;
end;

procedure Tfrm_Borrow.PageControl1Change(Sender: TObject);
begin
  case PageControl1.ActivePageIndex of
  0:begin
      DataSource1.DataSet:=Table1;
      Table1.Open;
    end;
  1:begin
      DataSource1.DataSet:=Query1;
      AllRec;
    end;
  end;
end;

procedure Tfrm_Borrow.SpeedButton1Click(Sender: TObject);
var
  SQLStr,SQLAll,Log:String;
  SQLTemp:Pchar;
  arrstr:array[1..5]of String;
  i,l:integer;
  function getsth(CurrEdit:TEdit):boolean;
  begin
    result:=false;
    if CurrEdit.Text<>'' then
      result:=true;
  end;
begin
  SQLAll:='';
  SQLStr:='SELECT * FROM "Borrow.db" WHERE ';
  if RadioGroup1.ItemIndex=1 then Log:='OR' else Log:='AND';
  if Getsth(Edit_name) then
    arrstr[1]:='(借用人='''+Edit_name.Text+''')';
  if Getsth(Edit_No) then
    arrstr[2]:='(仪器编号='''+Edit_No.Text+''')';
  if Getsth(Edit_DateOut) then
    arrstr[3]:='(借用日期='''+Edit_DateOut.Text+''')';
  if Getsth(Edit_DateIn) then
    arrstr[4]:='(归还日期='''+Edit_DateIn.Text+''')';
  arrstr[5]:='';
  for i:=1 to 4 do
  begin
    arrstr[5]:=arrstr[5]+arrstr[i];
    if arrstr[i]<>'' then
      SQLAll:=SQLAll+Log+arrstr[i];
  end;
  if arrstr[5]='' then
  begin
    showmessage('没有查询项目？');
    exit;
  end;
  
  l:=strlen(Pchar(SQLAll));
  GetMem(SQLTemp,l);
  SQLTemp^ := Chr(0);

  if SQLAll[1]='O' then
    StrCat(SQLTemp,Pchar(SQLAll)+2);
  if SQLAll[1]='A' then
    StrCat(SQLTemp,Pchar(SQLAll)+3);

  SQLStr:=SQLStr+SQLTemp+' ORDER BY 借用人,仪器编号,借用日期,归还日期';
  FreeMem(SQLTemp);
//  Application.MessageBox(Pchar(SQLStr),'预查询的SQL语句',MB_OK);

  with Query1 do
  begin
    SQL.Clear;
    SQL.Add(SQLStr);
    Prepare;
    ExecSQL;
    Open;
  end;
end;

procedure Tfrm_Borrow.DataSource1DataChange(Sender: TObject;
  Field: TField);
begin
  FormActivate(Sender);
end;

procedure Tfrm_Borrow.FormActivate(Sender: TObject);
begin
  MainForm.StatusBar.Panels[1].Text:='仪器借用库纪录导航信息：第'+inttostr(DataSource1.DataSet.RecNo)+'笔纪录-总共'+inttostr(DataSource1.DataSet.RecordCount)+'笔纪录';
end;

end.