set_mapping

this will report as many columns as mapping.length, and for each value at position 'i' in mapping, this will report the 'i'th column, mapped to the wrapped data model column at position mapping[i].

For example if mapping is {3, 4, 0}, then this will report 3 columns, respectively mapped to the 4th, 5th and 1st columns of the wrapped data model (as column numbers start at 0).

If mapping is null, then no mapping is done and this's columns will be the same as the wrapped data model.

If a column in mapping does not exist in the wrapped data model, then it is simply ignored (no error reported).

Please note that if this has already been used and if the wrapped data model offers a cursor forward access mode, then this method will return false and no action will be done.

If the mapping is applied, then any existing iterator will be invalid, and this is reset as if it had just been created.

Parameters:

this	a DataAccessWrapper object
mapping	an array of int which represents the mapping between this's columns and the columns of the wrapped data model
mapping_size	the size of mapping.

Returns:

true if the mapping actually changed