FireDAC 下的 Sqlite [5] - 数据的插入、更新、删除

发布时间：2020-12-12 23:51:55 所属栏目：百科来源：网络整理

导读：先在空白窗体上添加: TFDConnection、TFDPhysSQLiteDriverLink、TFDGUIxWaitCursor、TFDQuery、TDataSource、TDBGrid(并在设计时关联好). 你也可以复制下面文本框中的内容,然后直接往窗体上贴,以快速完成以上的添加过程: object DBGrid1: TDBGrid Left = 16

先在空白窗体上添加: TFDConnection、TFDPhysSQLiteDriverLink、TFDGUIxWaitCursor、TFDQuery、TDataSource、TDBGrid(并在设计时关联好).

你也可以复制下面文本框中的内容,然后直接往窗体上贴,以快速完成以上的添加过程:
object DBGrid1: TDBGrid Left = 16 Top = 88 Width = 361 Height = 329 DataSource = DataSource1 TabOrder = 0 TitleFont.Charset = DEFAULT_CHARSET TitleFont.Color = clWindowText TitleFont.Height = -11 TitleFont.Name = 'Tahoma' TitleFont.Style = [] end object FDConnection1: TFDConnection Left = 34 Top = 24 end object FDPhysSQLiteDriverLink1: TFDPhysSQLiteDriverLink Left = 143 Top = 24 end object FDGUIxWaitCursor1: TFDGUIxWaitCursor Provider = 'Forms' Left = 260 Top = 24 end object FDQuery1: TFDQuery Connection = FDConnection1 Left = 344 Top = 24 end object DataSource1: TDataSource DataSet = FDQuery1 Left = 420 Top = 24 end object Button1: TButton Left = 400 Top = 88 Width = 75 Height = 25 Caption = 'Button1' TabOrder = 1 OnClick = Button1Click end object Button2: TButton Left = 400 Top = 136 Width = 75 Height = 25 Caption = 'Button2' TabOrder = 2 OnClick = Button2Click end object Button3: TButton Left = 400 Top = 192 Width = 75 Height = 25 Caption = 'Button3' TabOrder = 3 OnClick = Button3Click end object Button4: TButton Left = 400 Top = 240 Width = 75 Height = 25 Caption = 'Button4' TabOrder = 4 OnClick = Button4Click end end

代码:

{建立}
procedure TForm1.FormCreate(Sender: TObject);
const
  dbPath = 'C:TempSQLiteTest.sdb';
  strTable = 'CREATE TABLE MyTable(Id integer PRIMARY KEY AUTOINCREMENT,Name string(10),Age byte)'; //Id,Name,Age 三个字段
                                                                                                      //integer PRIMARY KEY AUTOINCREMENT: 自增字段
begin
  if FileExists(dbPath) then DeleteFile(dbPath);

  FDConnection1.ConnectionString := 'DriverID=SQLite; Database=' + dbPath;
  FDConnection1.ExecSQL(strTable);

  FDQuery1.Open('SELECT * FROM MyTable');
end;

{插入}
procedure TForm1.Button1Click(Sender: TObject);
const
  strInsert = 'INSERT INTO MyTable(Name,Age) VALUES(:name,:age)'; //:name,:age 的方式(后面还要以数组的方式给出相应的值),这比字符串的 Format 函数还要方便.
begin
  FDConnection1.ExecSQL(strInsert,['AAA',11]);
  FDConnection1.ExecSQL(strInsert,['BBB',22]);
  FDConnection1.ExecSQL(strInsert,['CCC',33]);
  FDConnection1.ExecSQL(strInsert,['DDD',44]);
  FDConnection1.ExecSQL(strInsert,['EEE',55]);
  FDQuery1.Refresh;
end;

{更新}
procedure TForm1.Button2Click(Sender: TObject);
begin
  FDConnection1.ExecSQL('UPDATE MyTable SET Age=:a WHERE Name=:n',[Random(100),'AAA']);
  FDQuery1.Refresh;
end;

{删除}
procedure TForm1.Button3Click(Sender: TObject);
begin
  FDConnection1.ExecSQL('DELETE FROM MyTable WHERE Age>33');
  FDQuery1.Refresh;
end;

{查询符合条件的第一个结果}
procedure TForm1.Button4Click(Sender: TObject);
var
  V: Variant;
begin
  V := FDConnection1.ExecSQLScalar('SELECT Age FROM MyTable WHERE Name = :x',['BBB']);
  ShowMessage(V);
end;

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!