set_mapping
Description:
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 |
Returns:
true if the mapping actually changed |