epriestley 877cb136e8 Add an assocations-like "Edges" framework ... Summary: We have a lot of cases where we store object relationships, but it's all kind of messy and custom. Some particular problems: - We go to great lengths to enforce order stability in Differential revisions, but the implementation is complex and inelegant. - Some relationships are stored on-object, so we can't pull the inverses easily. For example, Maniphest shows child tasks but not parent tasks. - I want to add more of these and don't want to continue building custom stuff. - UIs like the "attach stuff to other stuff" UI need custom branches for each object type. - Stuff like "allow commits to close tasks" is notrivial because of nonstandard metadata storage. Provide an association-like "edge" framework to fix these problems. This is nearly identical to associations, with a few differences: - I put edge metadata in a separate table and don't load it by default, to keep edge rows small and allow large metadata if necessary. The on-edge metadata seemed to get abused a lot at Facebook. - I put a 'seq' column on the edges to ensure they have an explicit, stable ordering within a source and type. This isn't actually used anywhere yet, but my first target is attaching commits to tasks for T904. Test Plan: Made a mock page that used Editor and Query. Verified adding and removing edges, overwriting edges, writing and loading edge data, sequence number generation. Reviewers: btrahan Reviewed By: btrahan CC: aran, 20after4 Differential Revision: https://secure.phabricator.com/D2088		2012-04-04 15:30:21 -07:00
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init	Simplify database initialization, fix default data	2011-05-02 13:38:46 -07:00
patches	Add an assocations-like "Edges" framework	2012-04-04 15:30:21 -07:00