delphi7 TADOConnection TADODataSet 简单应用

unit DBOperation;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ComCtrls, StdCtrls, DB, ADODB, MemoExt;
{
INSERT INTO [testDB].[dbo].[stu]([ID],[name],[score])VALUES(3,'ccc',30)
SELECT [ID],[name],[score] FROM [testDB].[dbo].[stu]
}
type
TForm1 = class(TForm)
grp1: TGroupBox;
grp2: TGroupBox;
statDBConnction: TStatusBar; //在Object Inspector中的panel属性页中添加两个 panel ,在第一个panel用来标志数据是否连接
btnConnectDB: TButton;
conConnectionSqlServer: TADOConnection; //在ADO组件页 非可视化控件 拖到窗体 用于数据库的连接
btnexecutesql: TButton;
edtSql: TEdit;
edtExecuteSql: TEdit;
btnExecutesqlReturnSet: TButton;
mmoMessage1: TMemoExt;
procedure btnConnectDBClick(Sender: TObject);
procedure ExecuteSql(const sql :string);                           //可以执行没有返回记录的sql语句
function ExecutesqlReturnRecord(const sql :string):TADODataSet;    //可以执行  有返回记录的sql语句
procedure btnexecutesqlClick(Sender: TObject);
procedure btnExecutesqlReturnSetClick(Sender: TObject);

private
{ Private declarations }
bDBisConnected:Boolean;
public
{ Public declarations }
function  DbConnect:Boolean;
end;

var
Form1: TForm1;

implementation

{$R *.dfm}
function  TForm1.DbConnect:Boolean;//封装一个数据库连接函数
begin
Result := false;
if not bDBisConnected then
begin
with conConnectionSqlServer do
begin
Connected := False;
//TADOConnection 属性1 设置连接字符串参数
ConnectionString  := 'Provider=SQLOLEDB.1;Persist Security Info=False;User ID=sa;Initial Catalog=testDB;password =123456;Data Source=LJF-PC\LJF';
try
ConnectionTimeout := 20;//TADOConnection 属性2 连接超时等待时间
CommandTimeout := 30 ;//TADOConnection 属性3 执行命令超时时间
Connected:=True;   //TADOConnection 属性4 设置连接也可以用于判断是否连接
//    ConnectOptions :=coConnectUnspecified;//TADOConnection 属性 5 用来设置同步或异步连接 默认同步，连接数据库很慢可以用异步coConnectUnspecified, coAsyncConnect
Result := True;
bDBisConnected := True;
except
Result :=False;
bDBisConnected := False;
ShowMessage('not connected');  //
raise;
//  Exit;
end;
end;
end else
Result := True;
end;
procedure TForm1.btnConnectDBClick(Sender: TObject);
begin
if DbConnect then
statDBConnction.Panels[0].Text := '数据库已连接!'
else
statDBConnction.Panels[0].Text := '数据库未连接!';
end;

procedure TForm1.ExecuteSql(const sql :string); //可以执行没有返回记录的sql语句
var
lCursor: TCursor;
begin
if bDBisConnected then
begin
with conConnectionSqlServer do
begin
lCursor := Screen.Cursor;
try
try
//ZWH 2006-01-06 modify
Screen.Cursor := crSQLWait;
Execute(sql);//执行
Screen.Cursor := lCursor;
except
on E: Exception do
begin
ShowMessage(E.Message);
Raise;
Exit;
end;
end;
finally
Screen.Cursor := lCursor;
end;
end;

end;
end;

procedure TForm1.btnexecutesqlClick(Sender: TObject);
begin
ExecuteSql(edtSql.Text);//
end;

function TForm1.ExecutesqlReturnRecord(const sql :string):TADODataSet;
var
lCursor: TCurSor;
begin
Result := nil;
try
Result := TAdoDataset.Create(nil);
Result.Connection := Form1.conConnectionSqlServer;
Result.LockType := ltUnspecified;    //用来设置或取得Dataset打开时，记录如何锁定  1 ltUnspecified不指定锁定类型 ltReadOnly只读 ltBatchOptimistic 批量优化锁定....
Result.CommandTimeout := 1800;
if bDBisConnected then
begin
Result.Close;
Result.CommandText := sql;
lCursor := Screen.Cursor;
Screen.Cursor := crSQLWait;
try
Result.Open;//Derived from TDataSet //open相当于将active属性设置为true,Dataset状态为打开，也将触发一些相应的事件 ，数据集状态为dsBrowse
Screen.Cursor := crArrow;
except
on E: Exception do
begin
ShowMessage(E.Message);
raise;
end;
end;
end;
;
except
on E: Exception do
begin
ShowMessage(E.Message);
raise;
end;
end;
end;
procedure TForm1.btnExecutesqlReturnSetClick(Sender: TObject);
var
dsRecord:TADODataSet;
i:Integer;
begin
dsRecord := ExecutesqlReturnRecord(edtExecuteSql.Text);

with dsRecord do
begin
First;
for i:= 1 to RecordCount - 1 do
begin
mmoMessage1.Lines.Add(FieldByName('ID').AsString+  FieldByName('name').AsString+ FieldByName('score').AsString + #13#10);
Next;
end;
end
end;

end.