FireDAC.Comp.Client.TFDRdbmsDataSet.OnError

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Delphi

property OnError: TFDErrorEvent read GetOnError write SetOnError;

C++

__property Firedac::Stan::Error::TFDErrorEvent OnError = {read=GetOnError, write=SetOnError};

Properties

Type	Visibility	Source	Unit	Parent
event	public	FireDAC.Comp.Client.pas FireDAC.Comp.Client.hpp	FireDAC.Comp.Client	TFDRdbmsDataSet

Description

An event that fires when an error happens while the dataset is communicating with a DBMS.

The OnError event fires when the dataset executes one of the following operations and an error happens:

• Prepare. The dataset is preparing the DBMS command text for execution.
• Open. The dataset is executing the DBMS command to open the cursor.
• Execute, ExecSQL, ExecProc. The dataset is executing the DBMS command text.
• Navigation methods. The dataset is fetching rows from the cursor.

The event handler of OnError receives the following parameters:

• ASender is the RDBMS dataset.
• AInitiator is the object that raises the exception.
• AException is the exception. It is usually an instance of EFDDBEngineException.

You can handle OnError to analyze and modify the exception object. You can even create a new exception object and assign it to AException; if you do so, you must free the original exception object.

If AException is an instance of EFDDBArrayExecuteError, then it is a case of Array DML error handling.

To centralize error handling, you may consider using TFDCustomConnection.OnError.

See Also

• FireDAC.Comp.Client.TFDCustomQuery.ExecSQL
• FireDAC.Comp.Client.TFDCustomStoredProc.ExecProc
• FireDAC.Comp.Client.TFDRdbmsDataSet.Prepare
• FireDAC.Stan.Error.EFDDBArrayExecuteError
• FireDAC.Stan.Error.EFDDBEngineException
• FireDAC.Comp.Client.TFDCustomConnection.OnError

Samples

• FireDAC TFDQuery Batch Error Handling sample