#24 Delaying command translation in TInstantSelector

[Nando Dessena]

Each time the value of TInstantSelector.Command
changes, the whole command is transferred to the
internal TInstantQuery object which calls its own
TranslateCommand method to translate it. This makes it
impossible to set a IQL command in
TInstantSelector.Command a bit at a time:

Selector.Command.Add('select * from ...');
Selector.Command.Add('where ...');
Selector.Open;

The code above will raise an exception as soon as the
first line is executed. It would be better if
TInstantSelector or TInstantQuery would delay the
command translation until it is necessary, i.e. just
before opening the cursor.