reference

CCK field type 'View Reference' which allows users to link to, or include views into nodes.

Very well maintained, hugely informative project page.

when you assign (not by reference) a PHP5 object to a new variable, that integer handle is copied into the new variable, but it still points at the same instance, because it's still the same number.

Bottom line is it is like being passed by reference, but not quite, and it is better so long as you don't try to pass by reference. Get &= and such out of your PHP 5 code.

We encountered the necessity for referemtial integrity of nodereference fields in the PDonline project. To prevent deletion of nodes that are referenced by others there is no backend solution. Neither does this promising new project implement it so far. It seems to be an impossible task given the way the hook system and the database layer are designed.

This module provides a method to enforce referential integrity rules for CCK user and node reference fields.

Allows users to create named relationships between each other. It is the basic building block for a social networking site, or any site where users are aware of one another, and communicate.

There are many features on offer. It'd be worth your while to check it out.

Admins create relationship types (friend, coworker, etc). Relationship types can be setup to be one-way or mutual. If a relationship type is one-way (subscriber) only the requester is shown as relating to the requestee. Relationship types can also be set as needing or not needing approval.

This views module creates a relationship that ties the location of a referenced node to the referring node.

The overall purpose of the Nodereference Explorer module is to provide a comfortable and user-friendly way of referencing content. Content authors should be able to link internal arbitrary nodes, e. g. content types such as pages, stories, news, images etc., to each other. Typical use-cases are for instance: