FireDAC 下的 Sqlite [5] - 數據的插入、更新、刪除

先在空白窗體上添加: TFDConnection、TFDPhysSQLiteDriverLink、TFDGUIxWaitCursor、TFDQuery、TDataSource、TDBGrid(並在設計時關聯好).

你也可以複製下面文本框中的內容, 然後直接往窗體上貼, 以快速完成以上的添加過程:

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

---

代碼:

---

{建立}
procedure TForm1.FormCreate(Sender: TObject);
const
  dbPath = 'C:\Temp\SQLiteTest.sdb';
  strTable = 'CREATE TABLE MyTable(Id integer PRIMARY KEY AUTOINCREMENT, Name string(10), Age byte)'; //Id, Name, Age 三個字段
                                                                                                      //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(後面還要以數組的方式給出相應的值), 這比字符串的 Format 函數還要方便.
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;

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

{查詢符合條件的第一個結果}
procedure TForm1.Button4Click(Sender: TObject);
var
  V: Variant;
begin
  V := FDConnection1.ExecSQLScalar('SELECT Age FROM MyTable WHERE Name = :x', ['BBB']);
  ShowMessage(V);
end;