学习 SQL 语句 - Select(1): 指定表

//选择 country 表中的所有字段
SELECT * FROM country

{虽然 SQL 并不区分大小写, 但应习惯把关键字大写}

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls, Grids, DBGrids, DB, ADODB;

type
TForm1 = class(TForm)
Panel1: TPanel;
Button1: TButton;
Button2: TButton;
DBGrid1: TDBGrid;
DataSource1: TDataSource;
ADODataSet1: TADODataSet;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

{查看数据库 dbdemos.mdb 中的 country 表}
procedure TForm1.Button1Click(Sender: TObject);
begin
ADODataSet1.Close;
ADODataSet1.CommandText := 'SELECT * FROM country';
ADODataSet1.Open;
end;

{查看数据库 dbdemos.mdb 中的 customer 表}
procedure TForm1.Button2Click(Sender: TObject);
begin
with ADODataSet1 do begin
Close;
CommandText := 'SELECT * FROM customer';
Open;
end;
end;

{控件关联、连接数据库: dbdemos.mdb}
procedure TForm1.FormCreate(Sender: TObject);
var
mdbFile: string;
begin
{获取 CodeGear 共享安装的数据文件: dbdemos.mdb 的路径}
mdbFile := GetEnvironmentVariable('COMMONPROGRAMFILES'); {C:\Program Files\Common Files}
mdbFile := mdbFile + '\CodeGear Shared\Data\dbdemos.mdb';

ADODataSet1.ConnectionString := 'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=' +
mdbFile + ';Persist Security Info=False';

DBGrid1.DataSource := DataSource1;
DataSource1.DataSet := ADODataSet1;
end;

end.