DataAccessWrapper.setMapping

wrapper will report as many columns as mapping_size, and for each value at position 'i' in mapping, wrapper will report the 'i'th column, mapped to the wrapped data model column at position mappingi. For example if mapping is {3, 4, 0}, then wrapper 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 wrapper'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 wrapper 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 wrapper is reset as if it had just been created.

class DataAccessWrapper
bool
setMapping
(
int[] mapping = null
)

Parameters

mapping int[]

an array of #gint which represents the mapping between wrapper's columns and the columns of the wrapped data model

Return Value

Type: bool

true if the mapping actually changed