(PECL solr >= 0.9.2)
SolrInputDocument::merge — Merges one input document into another
Merges one input document into another.
sourceDocThe source document.
overwrite
If this is TRUE it will replace matching fields in the destination document.
Restituisce TRUE in caso di successo, FALSE in caso di fallimento. In the future, this will be modified to return the number of fields in the new document.