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

1 files changed, 4 insertions, 3 deletions

diff --git a/nova/openstack/common/db/sqlalchemy/session.py b/nova/openstack/common/db/sqlalchemy/session.py
index a3f4283d0..093d8b082 100644
--- a/nova/openstack/common/db/sqlalchemy/session.py
+++ b/nova/openstack/common/db/sqlalchemy/session.py
@@ -386,14 +386,15 @@ def _raise_if_duplicate_entry_error(integrity_error, engine_name):
     """
 
     def get_columns_from_uniq_cons_or_name(columns):
-        # note(boris-42): UniqueConstraint name convention: "uniq_c1_x_c2_x_c3"
-        # means that columns c1, c2, c3 are in UniqueConstraint.
+        # note(vsergeyev): UniqueConstraint name convention: "uniq_t0c10c2"
+        #                  where `t` it is table name, `0` it is delimiter and
+        #                  columns `c1`, `c2` are in UniqueConstraint.
         uniqbase = "uniq_"
         if not columns.startswith(uniqbase):
             if engine_name == "postgresql":
                 return [columns[columns.index("_") + 1:columns.rindex("_")]]
             return [columns]
-        return columns[len(uniqbase):].split("_x_")
+        return columns[len(uniqbase):].split("0")[1:]
 
     if engine_name not in ["mysql", "sqlite", "postgresql"]:
         return