Hi all,
i am writing a python script which parse an xml file (python lxml) and
import it into a sqlite db, and it works.
The xml file size is about 30Mb and the import operation takes about 15
minutes (do you think is too much? is there something i can do to speed up
the process?)
This is a piece of the import function:
...
for definition in definitions.getchildren(): #iterate for every xml children
node
defInst = SQLTableBuilder_Definition.DefinitionClass(definition) #read
and write on db some attribute of the node
...
if subbaElem1.tag == mainNS + "platform": #another loop iterate for
every sub-node of the definition node
platf = SQLTableBuilder_Platform.PlatformClass()
platf.setPlatform(str(subbaElem1))
platf.platformId_fk = defInst.defId
session.add(platf)
session.commit()
...
session.add(defInst)
session.commit()
where DefinitionClass contains the attributes declaration (primary_key,
column(string), etc.) and a Foreign Key.
There is a relation between the definition table and the platform table (one
or more platforms - Operating System - can be associated to a single
definition) so,
in the platform table, i've added the following: platformId_fk =
Column('definitionId_fk', Integer, ForeignKey('definitions.defId'))
All my ORM-Classes are declared within n different classes within n
different python modules so, i've included the needed imports everytime i
needed it.
And i suppose this is a problem, at least for me, sometime, because when i
try to add: PlatformRel =
relation(SQLTableBuilder_Definition.DefinitionClass, backref="platform")
within my platformClass, i got: 'list' object has no attribute
'_sa_instance_state' :/
So, i've tried to "manually" set the foreign key, as you can see above. In
the documentation (http://www.sqlalchemy.org/docs/ormtutorial.html) i read:
" SQLAlchemy is automatically aware of many-to-one/one-to-many based on
foreign keys." Does this mean that what i've done is correct or i'm a little
confused? If i "manually" set a foreign key value, does sqlalchemy
understand that a relation between two tables exists?
Thanks for your attention.
---
Masetto
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