FireDAC 下的 Sqlite [12] - 备忘录(草草结束这个话题了)

发布时间：2020-12-12 19:43:06 所属栏目：百科来源：网络整理

导读：该话题的继续延伸主要就是 SQL 的语法了,草草收场的原因是现在的脑筋已经进入了 IntraWeb 的世界. 相关备忘会随时补充在下面: //连接多个数据库的参考代码: FDConnection1.ExecSQL( 'ATTACH ' 'c:hr.sdb' ' AS hr' );FDConnection1.ExecSQL( 'ATTACH ' 'c:

该话题的继续延伸主要就是 SQL 的语法了,草草收场的原因是现在的脑筋已经进入了 IntraWeb 的世界.

相关备忘会随时补充在下面:

//连接多个数据库的参考代码:
FDConnection1.ExecSQL('ATTACH ''c:hr.sdb'' AS hr');
FDConnection1.ExecSQL('ATTACH ''c:cust.sdb'' AS cust');
FDQuery1.Open('select * from "Orders" o ' +
 'left join hr."Employees" e on o.EmployeeID = e.EmployeeID ' +
 'left join cust."Customers" c on o.CustomerID = c.CustomerID');


//SQLite_OnAuthorize 参考代码:
procedure TForm1.FormCreate(Sender: TObject);
begin
 FDConnection1.Connected := True;
 TSQLiteDatabase(FDConnection1.ConnectionIntf.CliObj).OnAutorize := DoAuthorize;
 FDQuery1.Open;
end;

procedure TForm1.DoAuthorize(ADB: TSQLiteDatabase; ACode: Integer; const AArg1,AArg2,AArg3,AArg4: String; var AResult: Integer);
begin
 Memo1.Lines.Add(Format('%d - %s - %s - %s - %s',[ACode,AArg1,AArg4]));
 if ACode = SQLITE_DELETE then
  AResult := SQLITE_DENY
 else
  AResult := SQLITE_OK;
end;


//SQLite_OnUpdate 参考代码:
procedure TForm1.FormCreate(Sender: TObject);
begin
 FDConnection1.Connected := True;
 TSQLiteDatabase(FDConnection1.ConnectionIntf.CliObj).OnUpdate := DoUpdate;
 FDQuery1.Open;
end;

procedure TForm1.DoUpdate(ADB: TSQLiteDatabase; AOper: Integer; const ADatabase,ATable: String; ARowid: sqlite3_int64);
begin
 Memo1.Lines.Add(Format('%d - %s - %s - %u',[AOper,ADatabase,ATable,ARowid]));
end;


//快速选择到行:
SELECT * FROM Orders WHERE ROWID = :RID

//TFDMemTable 代替 TClientDataSet
<pre class="Delphi">procedure TForm1.FormCreate(Sender: TObject);
begin
 with FDMemTable1.FieldDefs.AddFieldDef do
 begin
  Name := 'word';
  DataType := ftString;
  Size := 50;
 end;

 with FDMemTable1.FieldDefs.AddFieldDef do
 begin
  Name := 'ph';
  DataType := ftString;
  Size := 50;
 end;

 with FDMemTable1.FieldDefs.AddFieldDef do
 begin
  Name := 'note';
  DataType := ftString;
  Size := 255;
 end;

 with FDMemTable1.FieldDefs.AddFieldDef do
 begin
  Name := 'num';
  DataType := ftInteger;
 end;

 FDMemTable1.IndexDefs.Add('Index_1','word',[ixPrimary]);
 FDMemTable1.CreateDataSet;
end;

 
 
//并发相关: http://docwiki.embarcadero.com/RADStudio/XE6/en/Using_SQLite_with_FireDAC#Locking_and_Concurrent_Updates

（编辑：李大同）

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