Hi,
in your DB view tables are joined and database views implement an inner join (you can check here: http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21ecab446011d189700000e8322d00/content.htm), that's why the system extracts only 50 records.
It's not possible to have all the 1000 records using a database view.
Marco