Re: eagerly fetching joined objects

Thanks!  Sorry, my email filter moved this into a hidden folder.
I'll take a look :)  Here's hoping
-S

-----Original Message-----
From: Simon Cross [mailto:hodgestar <at> gmail.com] 
Sent: Thursday, July 21, 2011 1:32 AM
To: Simon Laalo
Cc: sqlobject-discuss <at> lists.sourceforge.net
Subject: Re: [SQLObject] eagerly fetching joined objects

Hi

On Thu, Jul 21, 2011 at 2:07 AM, Simon Laalo
<slaalo <at> resiliencesoftware.com> wrote:
> I'm currently trying to improve my DB performance by reducing the number of queries
> and associated overhead while grabbing some SQLObjects from the DB.  I would like
> to have SQLObject fully populate the object graph for the objects I'm using since all
> joined objects will be read every time this object is loaded.

I encountered a similar need in one of my own projects and wrote a
caching version of RelatedJoin that you could probably take ideas from
for a caching version of MultipleJoin / ForeignKey.  You can find the
code at http://sutekh.svn.sourceforge.net/viewvc/sutekh/trunk/sutekh/sutekh/core/CachedRelatedJoin.py?revision=2873&view=markup.

I considered contributing it back to SQLObject but it's a bit finicky
to use -- one has to manually initialize the cache (see init_cache
method) and then flush the cache (flush_cache) or just particular
items (invalidate_cache_item) from within one's application as needed.

Schiavo

SQLObject 1.0.2

Hello!

I'm pleased to announce version 1.0.2, a bugfix release of branch 1.0
of SQLObject.

What is SQLObject
=================

SQLObject is an object-relational mapper.  Your database tables are described
as classes, and rows are instances of those classes.  SQLObject is meant to be
easy to use and quick to get started with.

SQLObject supports a number of backends: MySQL, PostgreSQL, SQLite,
Firebird, Sybase, MSSQL and MaxDB (also known as SAPDB).

Where is SQLObject
==================

Site:
http://sqlobject.org

Development:
http://sqlobject.org/devel/

Mailing list:
https://lists.sourceforge.net/mailman/listinfo/sqlobject-discuss

Archives:
http://news.gmane.org/gmane.comp.python.sqlobject

SQLObject 1.1.2

Hello!

I'm pleased to announce version 1.1.2, a bugfix release of branch
1.1 of SQLObject.

What is SQLObject
=================

SQLObject is an object-relational mapper.  Your database tables are described
as classes, and rows are instances of those classes.  SQLObject is meant to be
easy to use and quick to get started with.

SQLObject supports a number of backends: MySQL, PostgreSQL, SQLite,
Firebird, Sybase, MSSQL and MaxDB (also known as SAPDB).

Where is SQLObject
==================

Site:
http://sqlobject.org

Development:
http://sqlobject.org/devel/

Mailing list:
https://lists.sourceforge.net/mailman/listinfo/sqlobject-discuss

Archives:
http://news.gmane.org/gmane.comp.python.sqlobject

Vacation

Hi! I am taking a week off.

Oleg.
--

-- 
     Oleg Broytman            http://phdru.name/            phd <at> phdru.name
           Programmers don't die, they just GOSUB without RETURN.

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Re: Vacation

Have fun Oleg!

Cheers,
Daniel

> Hi! I am taking a week off.
>
> Oleg.

--

-- 
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Storing object from same table

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Re: Storing object from same table

On 13-08-11 15:43, Timo wrote:
> Hello, sorry if I use the wrong terminology, I just started with 
> SQLObject and databases in general.
>
> This is my current class:
> class Person(SQLObject):
>     name = StringCol(notNone=True)
>     father = StringCol(default='')
>     mother = StringCol(default='')
Sorry about the fuzz, after some more searching and experimenting, I 
came up with the following which seems to work fine:

class Person(SQLObject):
     name = StringCol(notNone=True)
     father = ForeignKey('Person', default=None)
     mother = ForeignKey('Person', default=None)

p1 = Person(name='John')
print p1, p1.father, p1.mother
p2 = Person(name='Jane')
print p2, p2.father, p2.mother
p3 = Person(name='Jeff', father=p1, mother=p2)
print p3, p3.father, p3.mother

Cheers,
Timo

>
> This stores the names for the person's father and mother, but when I 
> want to access their data, I need to fetch their names first and then 
> lookup their objects from the database. What I actually want, is that 
> father and mother are references to their own Person object. Is 
> something like this possible? I read about SingleJoin/MultipleJoin, 
> but it always references to another table.
>
> Cheers,
> Timo

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update and CONCAT

How would I do this in SQLObject? 

UPDATE
    Table
SET
    some_text = CONCAT(some_text, 'text')
WHERE
    id = 57

Is it just

table = Table.get(57)
table.some_text = table.some_text + "text"

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Re: UPDATE and CONCAT

On Sat, Aug 20, 2011 at 11:15:20PM +0000, Mark wrote:
> How would I do this in SQLObject? 
> 
> UPDATE
>     Table
> SET
>     some_text = CONCAT(some_text, 'text')
> WHERE
>     id = 57
> 
> Is it just
> 
> table = Table.get(57)
> table.some_text = table.some_text + "text"

   It depends on what you really want. Functionally, your SQL and python
code do the same thing but in different ways. SQL code works on the
server side and doesn't update the client side; python code performs
concatenation on the client side and sends an UPDATE like that:

UPDATE table SET some_text = new_text WHERE id = 57

   If you really want to call CONCAT or any other function do it in
SQLObject like this:

from sqlobject.sqlbuilder import Update, func
connection.query(
    Update(Table.sqlmeta.table,
        {'some_text': func.CONCAT(Table.q.some_text, 'text')},
        Test.q.id==57))

   You have to ask SQLObject to update the client side because
you updated the server side and you don't want python and SQL sides to
by desynchronized:

table.sync()

Oleg.
--

-- 
     Oleg Broytman            http://phdru.name/            phd <at> phdru.name
           Programmers don't die, they just GOSUB without RETURN.

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Re: UPDATE and CONCAT

Oleg Broytman <phd <at> phdru.name> writes:

>    It depends on what you really want. Functionally, your SQL and python
> code do the same thing but in different ways. SQL code works on the
> server side and doesn't update the client side; python code performs
> concatenation on the client side and sends an UPDATE like that:

Great thanks, it makes perfect sense.

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