Comment 4 for bug 1182054

Reviewed: https://review.openstack.org/30108
Committed: http://github.com/openstack/nova/commit/64ce647003b110771331d3daf92980729bd3988e
Submitter: Jenkins
Branch: master

commit 64ce647003b110771331d3daf92980729bd3988e
Author: Victor Sergeyev <email address hidden>
Date: Wed May 22 15:46:02 2013 +0300

    Rename unique constraints due to new convention.

    We have found that current constraint name convention allows us to create
    constraints with duplicate names. It happens if we add constraints
    in different tables with the same column names (for example, `name`,
    `deleted`). In this case we can not create new constraint in mysql due to
    database limitation (it requires constraint name to be unique within a
    database). To solve this issue unique constraint name convention has
    been changed from "uniq_c1_x_c2_x_c3" to "uniq_t0c10c20c3" where `t` is
    a table name and columns `c1`, `c2`, `c3` are in UniqueConstraint.
    Fixed unique constraints in models description.
    Synced db code from oslo (function `_raise_if_duplicate_entry_error()`
    modified respectively to new unique constraint name convention).

    blueprint db-enforce-unique-keys
    Fixes: bug 1182054

    Change-Id: I4122dfb910a07a1a423781ebc22e9ce50596a05d