for example, heres a beast of a unit test:
python test/orm/inheritance/query.py --log-debug=sqlalchemy.engine --
db oracle PolymorphicUnionsTest.test_primary_eager_aliasing
When you run on SQLite, one of the queries is:
SELECT anon_1.people_person_id AS anon_1_people_person_id,
anon_1.people_company_id AS anon_1_people_company_id,
anon_1.people_name AS anon_1_people_name, anon_1.people_type AS
anon_1_people_type, anon_1.engineers_person_id AS
anon_1_engineers_person_id, anon_1.engineers_status AS
anon_1_engineers_status, anon_1.engineers_engineer_name AS
anon_1_engineers_engineer_name, anon_1.engineers_primary_language AS
anon_1_engineers_primary_language, anon_1.managers_person_id AS
anon_1_managers_person_id, anon_1.managers_status AS
anon_1_managers_status, anon_1.managers_manager_name AS
anon_1_managers_manager_name, anon_1.boss_boss_id AS
anon_1_boss_boss_id, anon_1.boss_golf_swing AS anon_1_boss_golf_swing,
machines_1.machine_id AS machines_1_machine_id, machines_1.name AS
machines_1_name, machines_1.engineer_id AS machines_1_engineer_id
FROM (SELECT people.person_id AS people_person_id, people.company_id
AS people_company_id, people.name AS people_name, people.type AS
people_type, engineers.person_id AS engineers_person_id,
engineers.status AS engineers_status, engineers.engineer_name AS
engineers_engineer_name, engineers.primary_language AS
engineers_primary_language, managers.person_id AS managers_person_id,
managers.status AS managers_status, managers.manager_name AS
managers_manager_name, boss.boss_id AS boss_boss_id, boss.golf_swing
AS boss_golf_swing
FROM people LEFT OUTER JOIN engineers ON people.person_id =
engineers.person_id LEFT OUTER JOIN managers ON people.person_id =
managers.person_id LEFT OUTER JOIN boss ON managers.person_id =
boss.boss_id ORDER BY people.person_id
LIMIT 2 OFFSET 1) AS anon_1 LEFT OUTER JOIN machines AS machines_1
ON anon_1.engineers_person_id = machines_1.engineer_id ORDER BY
anon_1.people_person_id, machines_1.oid
of note is the anonymous label "anon_1_engineers_primary_language", 34
characters. This label is generated from an anonymous alias name
combined with a column name, which is itself a combination of the
original table name and column name. So theres three stages of name
generation represented here.
Here it is on oracle, including the result rows:
SELECT anon_1.people_person_id AS anon_1_people_person_id,
anon_1.people_company_id AS anon_1_people_company_id,
anon_1.people_name AS anon_1_people_name, anon_1.people_type AS
anon_1_people_type, anon_1.managers_person_id AS
anon_1_managers_person_id, anon_1.managers_status AS
anon_1_managers_status, anon_1.managers_manager_name AS
anon_1_managers_manager_name, anon_1.boss_boss_id AS
anon_1_boss_boss_id, anon_1.boss_golf_swing AS anon_1_boss_golf_swing,
anon_1.engineers_person_id AS anon_1_engineers_person_id,
anon_1.engineers_status AS anon_1_engineers_status,
anon_1.engineers_engineer_name AS anon_1_engineers_engineer_name,
anon_1.engineers_primary_language AS anon_1_engineers_primary_1,
machines_1.machine_id AS machines_1_machine_id, machines_1.name AS
machines_1_name, machines_1.engineer_id AS machines_1_engineer_id
FROM (SELECT people_person_id, people_company_id, people_name,
people_type, managers_person_id, managers_status,
managers_manager_name, boss_boss_id, boss_golf_swing,
engineers_person_id, engineers_status, engineers_engineer_name,
engineers_primary_language
FROM (SELECT people.person_id AS people_person_id, people.company_id
AS people_company_id, people.name AS people_name, people.type AS
people_type, managers.person_id AS managers_person_id, managers.status
AS managers_status, managers.manager_name AS managers_manager_name,
boss.boss_id AS boss_boss_id, boss.golf_swing AS boss_golf_swing,
engineers.person_id AS engineers_person_id, engineers.status AS
engineers_status, engineers.engineer_name AS engineers_engineer_name,
engineers.primary_language AS engineers_primary_language, ROW_NUMBER()
OVER (ORDER BY people.person_id) AS ora_rn
FROM people LEFT OUTER JOIN managers ON people.person_id =
managers.person_id LEFT OUTER JOIN boss ON managers.person_id =
boss.boss_id LEFT OUTER JOIN engineers ON people.person_id =
engineers.person_id)
WHERE ora_rn>1 AND ora_rn<=3) anon_1 LEFT OUTER JOIN machines
machines_1 ON anon_1.engineers_person_id = machines_1.engineer_id
ORDER BY anon_1.people_person_id, machines_1.machine_id
INFO:sqlalchemy.engine.base.Engine.0x..4c:{}
DEBUG:sqlalchemy.engine.base.Engine.0x..4c:Col
('ANON_1_PEOPLE_PERSON_ID', 'ANON_1_PEOPLE_COMPANY_ID',
'ANON_1_PEOPLE_NAME', 'ANON_1_PEOPLE_TYPE',
'ANON_1_MANAGERS_PERSON_ID', 'ANON_1_MANAGERS_STATUS',
'ANON_1_MANAGERS_MANAGER_NAME', 'ANON_1_BOSS_BOSS_ID',
'ANON_1_BOSS_GOLF_SWING', 'ANON_1_ENGINEERS_PERSON_ID',
'ANON_1_ENGINEERS_STATUS', 'ANON_1_ENGINEERS_ENGINEER_NAME',
'ANON_1_ENGINEERS_PRIMARY_1', 'MACHINES_1_MACHINE_ID',
'MACHINES_1_NAME', 'MACHINES_1_ENGINEER_ID')
DEBUG:sqlalchemy.engine.base.Engine.0x..4c:Row (2, 1, 'wally',
'engineer', None, None, None, None, None, 2, 'regular engineer',
'wally', 'c++', 3, 'Commodore 64', 2)
DEBUG:sqlalchemy.engine.base.Engine.0x..4c:Row (3, 1, 'pointy haired
boss', 'boss', 3, 'da boss', 'pointy', 3, 'fore', None, None, None,
None, None, None, None)
Where you can see that "anon_1_engineers_primary_language" becomes
"anon_1_engineers_primary_1" (27 characters) - this translation occurs
as late as possible. It shows up as that name in cursor.description,
and the ResultProxy translates that truncated name back to a name
matching the original column object.
On Jun 13, 2008, at 11:12 AM, Michael Bayer wrote:
>
>
> On Jun 13, 2008, at 3:58 AM, Egil Möller wrote:
>
>> I and a coworker are currently working on a patch-set to the oracle
>> driver for SA for this very reason, fixing issues like:
>>
>> * broken mangling of forbidden/to long table/column names
>
> really ? we have a lot of tests which pass fine for that, including
> when aliases are created, etc. In compiler.py, all names go through
> the same "length" filter no matter how they got generated (the only
> exception to this is the "too long index names" ticket which is
> strictly a schema thing). We have a "long labels" test specifically
> for this, and lots of ORM tests generate very long names as well (all
> of which work fine with Oracle). We did a tremendous amount of
> development on this a few years back and noone has had issues since.
>
> can you post a ticket with an example ? Also if producing fixes,
> keep in mind theres some compiler differences between 0.4 and 0.5, 0.5
> is the direction we're heading....
>
>>
>> * missing support for the BOOL data type
>
> there may or may not be a ticket for this (please post one if not)
>
>>
>> * missing support for boolean expressions in the column list (
>> select([tbl.c.col1 == tbl.c.col2]) ) (related to the last one above)
>
> ditto
> >
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