台州电大陈元的数据库应用程序设计离线作业(8)

代码： unit Unit1;

interface uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, Grids, DBGrids, DB, ADODB, ComCtrls, StdCtrls, ToolWin, ImgList; type

TFormTable = class(TForm)

ADOConnection1: TADOConnection; DataSource1: TDataSource; DBGrid1: TDBGrid; ToolBar1: TToolBar; TBAdd: TToolButton; Editname: TEdit; Label1: TLabel; Label2: TLabel; Label3: TLabel;

Editaddress: TEdit; Label4: TLabel; Editid: TEdit; Label5: TLabel; Label6: TLabel;

ComboBoxsex: TComboBox; DateBirthday: TDateTimePicker; TBUpdate: TToolButton; TBDelete: TToolButton; TBSelect: TToolButton; TBCommit: TToolButton; LabelMode: TLabel;

ToolButton6: TToolButton; Label8: TLabel;

ADOQuery1: TADOQuery; DataSource2: TDataSource; ADOTable1: TADOTable; ImageList1: TImageList;

procedure TBAddClick(Sender: TObject); procedure TBUpdateClick(Sender: TObject); procedure TBDeleteClick(Sender: TObject); procedure TBSelectClick(Sender: TObject); procedure FormPaint(Sender: TObject); procedure TBCommitClick(Sender: TObject); procedure DBGrid1DblClick(Sender: TObject); private

public

{ Public declarations } end; var

FormTable: TFormTable;

TBStatus : integer; //模式类型,0-查询，1-新增，2-修改，3-删除

SelMode : integer; //第一次按查询按钮进入查询模式--1，再按一次执行查询--2，其他情况下为--0

implementation

{$R *.dfm}

procedure TFormTable.TBAddClick(Sender: TObject); var maxid : integer; var date : string; begin

TBStatus := 1;

Editid.Enabled := false; Editname.Enabled := true; Comboboxsex.Enabled := true; DateBirthday.Enabled := true; Editaddress.Enabled := true; Editid.Text := ''; Editname.Text := ''; SelMode := 0;

LabelMode.Caption := '新增模式'; DBGrid1.DataSource := DataSource1;

date := FormatDateTime('yymm', now); With FormTable.ADOQuery1 do begin

ADOQuery1.Close; ADOQuery1.SQL.Clear;

ADOQuery1.SQL.Add('select max(substring(Id,6,3)) maxid from Students where substring(Id,2,4)=' + date); ADOQuery1.Open;

if (ADOQuery1.RecordCount = 0) then Editid.Text := 'S' + date + '001' else

begin if (ADOQuery1.FieldByName('maxid').Text = '') or (ADOQuery1.FieldByName('maxid').Text = 'NULL') then Editid.Text := 'S' + date + '001' else begin

maxid := StrToInt(ADOQuery1.FieldByName('maxid').Text); maxid := maxid + 1;

Editid.Text := 'S' + date + StringOfChar('0', 3-length(IntToStr(maxid))) + IntToStr(maxid); end;

end; end; end;

procedure TFormTable.TBUpdateClick(Sender: TObject); begin

TBStatus := 2;

Editid.Enabled := false; Editname.Enabled := true;

Comboboxsex.Enabled := true; DateBirthday.Enabled := true; Editaddress.Enabled := true; Editid.Text := ''; Editname.Text := ''; SelMode := 0;

LabelMode.Caption := '修改模式'; DBGrid1.DataSource := DataSource1; end;

procedure TFormTable.TBDeleteClick(Sender: TObject); begin

TBStatus := 3;

Editid.Enabled := false; Editname.Enabled := false; Comboboxsex.Enabled := false; DateBirthday.Enabled := false; Editaddress.Enabled := false; Editid.Text := ''; Editname.Text := ''; SelMode := 0;

LabelMode.Caption := '删除模式'; DBGrid1.DataSource := DataSource1; end;

procedure TFormTable.TBSelectClick(Sender: TObject); var id,ename,address:string; begin

if SelMode = 0 then begin

TBStatus := 0;

Editid.Enabled := true; Editname.Enabled := true; Comboboxsex.Enabled := true; DateBirthday.Enabled := true; Editaddress.Enabled := true; Editid.Text := ''; Editname.Text := ''; SelMode := 1;

LabelMode.Caption := '查询模式'; DBGrid1.DataSource := DataSource2; end

else if SelMode = 1 then begin

if Editid.Text = '' then id := 'null' else

id := ''''+Editid.Text+'''';

if Editname.Text = '' then ename := 'null' else

ename := ''''+Editname.Text+'''';

if Editaddress.Text = '' then address := 'null' else

address := ''''+Editaddress.Text+'''';

with ADOQuery1 do begin

ADOQuery1.Close; ADOQuery1.SQL.Clear;

ADOQuery1.SQL.Add('select Id, Name, Sex, Birthday, Address from Students' + ' where Id = isnull('+id+',Id)'+

' and Name = isnull('+ename+',Name)'+ ' and Sex = '+''''+Comboboxsex.Text+''''+

' and Birthday = '+''''+DateToStr(DateBirthday.Date)+''''+ ' and Address = isnull('+address+',Address)'); ADOQuery1.Open;

end; end; end;

procedure TFormTable.FormPaint(Sender: TObject); begin

//默认为查询模式，此模式下学号可以输入，其他模式下不可以输入 TBStatus := 0;

Editid.Enabled := true; Editid.Text := ''; SelMode := 1;

DBGrid1.DataSource := DataSource2; end;

procedure TFormTable.TBCommitClick(Sender: TObject);

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