Re: [gnome-db] gda_data_model_update_row syntax

[Paisa Seeluangsawat <paisa unt edu>]

Regarding to "the ability to update a row", this is probably what
gda_data_model_is_editable() is for.

I agree with moving provider specific functions into a separate
header.  This will also help tidy up the documentation a bit, since
regular users shouldn't have to care about these functions.

To prevent forcing user to cast off "const", I think we can provide
separate functions for editing.  As added benefits, it allows
providers to do special preparation, such as row locking or copying
the original record values.

A draft idea follows.  Comment please :-),

Paisa



const GdaRow*   gda_data_model_get_row (GdaDataModel *model, gint row);
GdaRow*         gda_data_model_get_updateable_row (
			GdaDataModel *model, gint row,
			LockType lock_type,  LockType *result);

// the following two can be overloaded in most languages binding
const GdaValue* gda_row_get_value (const GdaRow *row, gint num); 
GdaValue*	gda_row_get_updatable_value (GdaRow *row, gint num); 


enum LockType {
	NO_LOCK = 0;
	REFRESH;
	LOCK_ROW;	// default
	LOCK_TABLE;	// use this with caution

	CONFLICT = -2;
	NONEDITABLE = -1;
};


GdaRow *
gda_data_model_get_updateable_row (GdaDataModel *model,  gint row,
				   LockType lock_type,  LockType *result)
{
	if (model can't be edited)
		result = NONEDITABLE;
		return NULL;

	result = lock_type;
	if (result == LOCK_ROW)
		if (provider support row locking)
			lock the row;
			if (succeed)
				reselect the row to make sure the 
				content is uptodate;
			else
				result = CONFLICT;
				return NULL;
		else
			result = REFRESH;

	if (result == LOCK_TABLE)
		similar to above;

	if (result == REFRESH)
		reselect the row data;

	return GdaRow*
}