unit4.pas

利用数据库后SQL台操作的

unit Unit4;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, DBTables, StdCtrls;

type
  TForm4 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    ComboBox1: TComboBox;
    Button1: TButton;
    Button2: TButton;
    Query1: TQuery;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form4: TForm4;

implementation

uses Unit3, Unit7;

{$R *.dfm}

procedure TForm4.Button1Click(Sender: TObject);
var str1,str2:string;
begin
str1:=edit1.text;
str2:=edit2.text;

if(trim(edit1.text)='')then
begin
showmessage('用户名不能为空');
exit;
end;
if(trim(edit2.text)='')then
begin
showmessage('密码不能为空');
exit;
end;



with query1 do
begin
close;
sql.Clear;
sql.add('insert login values(:a,:b,:c)');
parambyname('a').asstring:=trim(edit1.text);
parambyname('b').asstring:=trim(edit2.text);
parambyname('c').asstring:=trim(combobox1.text);
execsql;
end;
form4.Close;
edit1.Text:='';
edit2.Text:='';
form3.adoquery1.active:=false;
form3.adoquery1.Active:=true;
form7.show;
form7.label1.caption:=('尊敬的用户你好，欢迎你的注册！');
form7.label2.caption:=('你的用户名是：'+str1);
form7.label3.caption:=('你的密码是：'+str2);













end;
procedure TForm4.Button2Click(Sender: TObject);
begin
close;
end;

procedure TForm4.Edit1Change(Sender: TObject);
begin
with query1 do
begin
close;
sql.Clear;
sql.Add('select * from login where name=:a');
parambyname('a').asstring:=trim(edit1.text);
open;
end;
if query1.RowsAffected>0 then
begin
showmessage('该用户名已存在');
edit1.text:='';
exit;
end;
end;

end.