Manipulating Data

You can use TFDConnection or TFDQuery objects to execute data manipulation commands. A TFDQuery object is more efficient for executing a query repeatedly since you can prepare statements to skip statement processing on subsequent executions.

Using TFDConnection

You can use the ExecSQL method of the TFDConnection class as a quick way to execute data manipulation commands. You can pass in parameters through the overloaded method; however, the statement is not prepared.

Note that the TFDConnection object does not return result sets, so it is not suitable for SELECT statements. Note as well that the Connected property of the TFDConnection object needs to be set to true.

Update

The following example executes a parameterized update:

RowsAffected := FDConnection1.ExecSQL('update Orders set Total=:Total where Id = :Id', ['John','6']);

Insert

The following example executes a parameterized insert:

RowsAffected := FDConnection1.ExecSQL('INSERT INTO Orders (Total) values (:Total)', ['Jon Doe']);

Delete

The following example executes a parameterized delete:

RowsAffected:= FDConnection1.ExecSQL('delete from Orders set Id = :Id', ['6']);

Using TFDQuery

TFDQuery objects can also return the rows affected by an operation and execute Prepared Statements. Use the ExecSQL method when no result set is returned. This method is overloaded. One way to invoke it is to specify the SQL statement in the SQL property:

FDQuery1.SQL.Text := 'update Orders set Total=:Total where Id = :Id';
FDQuery1.ParamByName('Total').AsString := 'John';
FDQuery1.ParamByName('Id').AsString := '6';
FDQuery1.ExecSQL;
RowsAffected := FDQuery1.RowsAffected;

Or, you can specify the statement and parameters as method arguments: