[dataimport] move cwmassive_constraint temporary table handling to the PGHelper class
with consistent renaming and some rationalization to avoid doing things several
times and have code slightly easier to grasp.
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/html/index.html
Files: /usr/share/doc/cubicweb-documentation/html/*