bazaar.core.Bazaar

Package bazaar :: Module core :: Class Bazaar

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Class Bazaar

The interface to get, modify, find and perform other tasks on application objects.

See Also: Broker bazaar.motor.Motor

Method Summary
	`__init__(self, cls_list, config, dsn, dbmod, seqpattern)` Start the Bazaar layer.
	`add(self, obj)` Add object to database.
	`closeDBConn(self)` Close database connection.
	`commit(self)` Commit pending database transactions.
	`connectDB(self, dsn)` Make new database connection.
	`delete(self, obj)` Delete object from database.
	`find(self, cls, query, param, field)` Find objects of given class in database.
	`getObjects(self, cls)` Get list of application objects.
	`init(self)` Initialize the Bazaar layer.
	`parseConfig(self, config)` Parse Bazaar configuration.
	`reloadObjects(self, cls, now)` Reload objects from database.
	`rollback(self)` Rollback database transactions.
	`setConfig(self, config)` Set Bazaar configuration.
	`update(self, obj)` Update object in database.

Instance Variable Summary
	`brokers`: Dictionary of brokers.
	`cls_list`: List of application classes.
	`dbmod`: Python DB API module.
	`dsn`: Python DB API database source name.
	`motor`: Database access object.

Method Details

init(self, cls_list, config=None, dsn='', dbmod=None, seqpattern=None)
(Constructor)

Start the Bazaar layer.

If database source name is not empty, then database connection is created.

Parameters:: cls_list - List of application classes.; config - Configuration object.; dsn - Database source name.; dbmod - Python DB API module.; seqpattern - Sequence command pattern.

add(self, obj)

Add object to database.

Parameters:: obj - Object to add.

closeDBConn(self)

Close database connection.

: See Also: bazaar.core.Bazaar.connectDB

commit(self)

Commit pending database transactions.

connectDB(self, dsn=None)

Make new database connection.

New database connection is created with specified database source name, which must conform to Python DB API Specification, i.e.:

   bazaar.connectDB('dbname=addressbook host=localhost port=5432 user=bird')

It is possible to reconnect with previous database source name, too:

   bazaar.connectDB()

Parameters:: dsn - Database source name.

See Also: bazaar.core.Bazaar.closeDBConn

delete(self, obj)

Delete object from database.

Object's primary key value is set to None.

Parameters:: obj - Object to delete.

find(self, cls, query, param=None, field=0)

Find objects of given class in database.

The method can be used in two ways.

First, simple dictionary can be passed as query:

   # iterator is returned, so its next() method is used to get
   # the object
   apple = bazaar.find(Article, {'name': 'apple'}).next()

Dictionary can contain objects as values, i.e.:

   bazaar.find(OrderItem, {'article': art})

Second, it is possible to use full power of SQL language:

   # find orders and their articles if order amount is greater
   # than 50$

   # find orders with the query
   query = """
       select O.__key__ from "order" O
       left outer join order_item OI on O.__key__ = OI.order_fkey
       left outer join article A on OI.article_fkey = A.__key__
       group by O.__key__ having sum(A.price) > 50
   """

   for ord in  bzr.find(Order, query):
       print ord                     # show order
       for oi in ord.items:          # show order's articles
           print oi.article

Parameters:: cls - Application class.; query - SQL query or dictionary.; param - SQL query parameters.; field - SQL column number which describes found objects' primary key values.

Returns:: Iterator of found objects.

getObjects(self, cls)

Get list of application objects.

Only objects of specified class are returned.

Parameters:: cls - Application class.

init(self)

Initialize the Bazaar layer.

parseConfig(self, config)

Parse Bazaar configuration.

Parameters:: config - Bazaar configuration.

reloadObjects(self, cls, now=False)

Reload objects from database.

If objects immediate reload is requested, then method returns iterator of objects being loaded from database.

Parameters:: cls - Application class.; now - Reload objects immediately.

See Also: bazaar.core.Bazaar.getObjects

rollback(self)

Rollback database transactions.

setConfig(self, config)

Set Bazaar configuration.

: See Also: parseConfig init bazaar.config.Config bazaar.config.CPConfig

update(self, obj)

Update object in database.

Parameters:: obj - Object to update.

Instance Variable Details

brokers

Dictionary of brokers. Brokers are mapped with its class application.

cls_list

List of application classes.

dbmod

Python DB API module.

dsn

Python DB API database source name.

motor

Database access object.

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