I have rewritten the CSV io functions (in trunk). Now they work
better, are more portable and should work on GAE.
They also have one cool new feature:
Consider this:
db=SQLDB('sqlite:memory:')
db.define_table('t1',SQLField('name'),SQLField('test'))
db.define_table('t2',SQLField('a',db.t1),SQLField('name'))
db.t1.insert(name='max')
db.t2.insert(a=1,name='tim')
The t2 record references the t1 record. Let's dump both tables:
open('t1.csv','w').write(db(db.t1.id>0).select())
open('t2.csv','w').write(db(db.t2.id>0).select())
They contain:
t1.id,t1.name
1,max
t2.id,t2.a,t2.name
1,1,tim
Now reimport, in the naive way,
db.t1.import_from_csv_file(open('t1.csv','r'))
db.t2.import_from_csv_file(open('t2.csv','r'))
and you get
t1.id,t1.name
1,max
2,max
t2.id,t2.a,t2.name
1,1,tim
2,1,tim
Nothing new here. The record t2.id==2 references t1.id==1 instead of
t1.id==2. This is not what one would expect since the new t2 record
should reference the new t1 record.
To fix this you can instead import in the following way:
remap={}
db.t1.import_from_csv_file(open('t1.csv','r'),remap)
db.t2.import_from_csv_file(open('t2.csv','r'),remap)
and you get
t1.id,t1.name
1,max
2,max
t2.id,t2.a,t2.name
1,1,tim
2,2,tim
Now t2.id==2 reference t1.id==2 instead of t1.id==1. This is one would
expect.
Summary: if you need to import multiple tables that reference each
other, pass a dictionary (the same) to all calls to
import_from_csv_file and web2py will take care of remapping the
reference indices. The dictionary is used to store the mapping between
the old 'id' and the new 'id'.
This can be used for remote database synchronization using CSV.
None is serialized as <NULL> to avoid csv shortcomings.
Massimo
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"web2py Web Framework" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/web2py?hl=en
-~----------~----~----~----~------~----~------~--~---
