5.Firedac错误信息

主要错误信息属性：

1.EFDDBEngineException

•   Errors -- TFDDBError对象集合.
• ErrorCount --错误的记录数
• Kind -- DBMS的错误集合.
• Message --错误消息.

2. TFDDBError属性:

• ErrorCode -- DBMS错误代码
• Kind -- DBMS的错误集合.
• Message --错误消息.  

处理OnError过程：

procedure TForm1.FDConnection1Error(ASender: TObject; const AInitiator: IFDStanObject;

  var AException: Exception);

var

  oExc: EFDDBEngineException;

begin

  if AException is EFDDBEngineException then begin

    oExc := EFDDBEngineException(AException);

    if oExc.Kind = ekRecordLocked then

      oExc.Message := 'Please, try the operation later. At moment, the record is busy'

    else if (oExc.Kind = ekUKViolated) and SameText(oExc[0].ObjName, 'UniqueKey_Orders') then

      oExc.Message := 'Please, provide the unique order information. It seems, your order was already put';

  end;

end;

FDConnection1.OnError := FDConnection1Error;