[sqlalchemy] Re: session issues in TG - automatic commits happening.
As I recall, this was discussed in TG forum sometime, and there is a nice way to disable this. Searching there might help... Sanjay --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Storing JSON objects, maybe OT
http://www.evolt.org/article/Four_ways_to_work_with_hierarchical_ data/17/4047/index.html I have to say I've seen better writeups on this topic - so be warned :) that looks very much like '1st 5 things i found about recursive data'. Choosing a strategy for storing hierarchical data in a database depends largely on how you will be retrieving the data (what kind of queries do you need to make). exactly. and one more thing, the way u store data may not be the way u retrieve it - i.e. u have one original copy that presents everything as is, and one pre-calculated/calculable-on-the-fly view/copy which u use for queries. and for differnt queries u may have different extracts/views. For example, storing a graph as links and nodes is fine to keep the original data, but is quite difficult for most (graph algorithmical) queries - procedural recursion is not SQL's piece of cake. Thus storing additional transient-closure of the graph (all possible end-to-end paths) is a way to go for some targets which need paths. Probably there are other solutions for other targets. have fun svil --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Storing JSON objects, maybe OT
Thanks Arnar! I´ll prefer to take this off the list since it is only slightly related to SQLAlchemy. On Jun 26, 2:28 am, Arnar Birgisson [EMAIL PROTECTED] wrote: On 6/25/07, voltron [EMAIL PROTECTED] wrote: Thank you very much for your feedback guys! I was very worried the whole day. I did some research and found this: http://www.evolt.org/article/Four_ways_to_work_with_hierarchical_data... I have to say I've seen better writeups on this topic - so be warned :) Choosing a strategy for storing hierarchical data in a database depends largely on how you will be retrieving the data (what kind of queries do you need to make). Actually, I would be reordering or editing page links using this method, the JSON data is passed to a tree widget I'm not sure what is the relation between your JSON issue and the hierarchical stuff. JSON is really only useful to serialize simple data structures in a way that is easy for Javascript code to deserialize. It won't help you particularly in designing a hierarchical database model. If you still need help and if you want to, feel free to tell us a bit more what you want to do. If it's not an SA issue you can mail me directly if you're more comfortable with that. Arnar --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Concurrency control using version_id_col
Hi Mike, Thanks a lot. It works fine (with or without default=0). The problem was in my TG application, which was not preserving version while populating the edit form. I made version as a hidden field in the form, and it works fine now. Sanjay --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: advanced mapping help
The mapper expects a class, but I can't define Content before ContentCollection and ContentCollection before Content... whhy? SA-wise u have no problem: class X: pass class Y: pass mapper(X, ... y=relation(Y,...) ... ) mapper(Y, ... x=relation(X,...) ... ) The problem might be only in your own classes (X,Y). some theory/experience: This is a problem in ordered declarative languages, where order of appearance is important and which usualy have a sort of 'Forward declarations' for that matter. Python itself is a sort of such language without Forward decl, but usualy declaration and usage are in different lifetimes/scopes (e.g. class declaration vs class-method-runtime are different scopes/lifetimes), so u never hit it. Well, If u try using it pure declaratively, in same lifetime/scope - then u have trouble. For python there 2 ways to workaround: - at the reference end/ refereee: use surrogates/aliases instead of real references, then at certain 'end-of-declarations' time go replace all reference to surogate with reference to real thing. May need some rework e.g. not to expect real things before runtime. i'm using this approach in my sa-wrapping pure declarative framework. - at the owner end/ referer: declare the class empty; then somewhat later put the contents in (the contents may be prepared early, but not in the class). This is not straight forward, uses pseudo __bases__ that are replaced with something full later. i'm using this in a 2-tier protocol generator, miming C/CORBA scope semantics in equivalent python classes. If u're interested i can give u some sources doing either one. but i am 95% sure u don't need them - they are of use only for large frameworks where u cant choose which is when nor where. ciao svil --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Relation ends up as a one-to-one, not a one-to-many
Hi,
I have the following property on an object, which is working fine:
class VulnResDesc:
...
@property
def rawvulns(self):
return VulnRes.select(
and_(VulnRes.c.targetid == self.targetid,
VulnMap.c.tool == VulnRes.c.tool,
VulnMap.c.toolvulnid == VulnRes.c.toolvulnid,
VulnMap.c.vulndescid == self.id))
The role of VulnMap is a bit funky in the query, but this is intentional.
Now, I am trying to code this as a relation instead of a property, the
following is what I've got so far:
VulnResDesc.mapper.add_property('rawvulns', relation(VulnRes.mapper,
primaryjoin = and_(VulnRes.c.targetid == VulnResDesc.c.targetid,
VulnMap.c.vulndescid == VulnResDesc.c.id,
VulnMap.c.tool == VulnRes.c.tool,
VulnMap.c.toolvulnid == VulnRes.c.toolvulnid),
foreign_keys = [VulnResDesc.c.targetid, VulnResDesc.c.id]))
This almost works, but it returns a single object, which I was expecting a
list. Any ideas what's up?
BTW, the reason I want to recode this is I'm hoping to use the eagerloader.
Still, to start with I'll settle for just getting it to work lazily :-)
Paul
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[sqlalchemy] Re: Relation ends up as a one-to-one, not a one-to-many
it might be stupid, but did u try use_list=True ? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Relation ends up as a one-to-one, not a one-to-many
Ah, that does it. Sorry, that really was stupid! If only I had scrolled down the docs a little bit :-) Thanks svilen. Paul On 6/26/07, svilen [EMAIL PROTECTED] wrote: it might be stupid, but did u try use_list=True ? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] alchemy mysql database problem
Hi,
I am currently using SQLAlchemy in the creation of a mysql database. I
use alchemy to create the tables and to access them but I use a python
script to collect the information from the necessary sources prepare
them and shove them into tab delimited 'out' files which i then load
into the tables using the mysql 'LOAD IN FILE' function.
These are my tables
AccessionsTable = Table('AccessionsTable',metadata,
Column('accession_number', String(20), primary_key=True),
Column('description',String(300)),
Column('seq_length',Integer),
Column('accessions_id',Integer)
)
AccessionsTable.create()
InstancesTable = Table('InstancesTable',metadata,
Column('inst_id',Integer,primary_key=True,autoincrement=True),
Column('oligomer',String(40)),
Column('instances', String),
Column('frequency',Integer),
Column('fisher_coef', Float),
Column('expectation_per_100kb', String),
Column('accession_number',String(20),ForeignKey('AccessionsTable.accession_number'))
)
InstancesTable.create()
OligosTable = Table('OligosTable', metadata,
Column('oligomer',String(40),ForeignKey('InstancesTable.oligomer'),
primary_key=True),
Column('word', String),
Column('word_length', Integer),
Column('descriptor', Integer),
Column('gc_cont', Float),
Column('melt_temp_wall', Float),
Column('melt_temp_nn', Float)
)
OligosTable.create()
This is what the command looks like
LOAD DATA INFILE '/db/test/01.ins' INTO TABLE InstancesTable FIELDS
TERMINATED BY '\t' LINES TERMINATED BY '\n';
My problem is that this specific table - InstancesTable has an
autoincremented primary key which was intended to be generated
automatically however the first value in each line in the file is
being shoved into it which breaks the operation. I am just curious if
theres an attribute i can specify for this column when i create the
table so that this doesnt happen.
Thanks
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[sqlalchemy] Table updates using data mapping
Could someone tell me how I would execute this SQL using data mapping? # SQL UPDATE users SET group=consultant WHERE group = contractor; # Mapped object user_mapper = mapper(User, users) user = User() Thanks --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Table updates using data mapping
Updates and inserts on the ORM side of the street are single-object kinds of
things. The pattern is to load a list of objects, make the appropriate
modifications to the those in-memory objects, and then issue a session
flush().
This type of
bulk operation is best done with the SQL generation portion of the library,
like so (using an implicit bound connection here):
users.update(users.c.group == contractor).execute({users.c.group =
consultant})
On 6/26/07, voltron [EMAIL PROTECTED] wrote:
Could someone tell me how I would execute this SQL using data mapping?
# SQL
UPDATE users SET group=consultant WHERE group = contractor;
# Mapped object
user_mapper = mapper(User, users)
user = User()
Thanks
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[sqlalchemy] Re: Table updates using data mapping
would I have to do something like this? sess = create_session() allusers = sess.query(User).select() for user in allusers: user.group = contractor print x.name On Jun 26, 10:40 pm, voltron [EMAIL PROTECTED] wrote: Could someone tell me how I would execute this SQL using data mapping? # SQL UPDATE users SET group=consultant WHERE group = contractor; # Mapped object user_mapper = mapper(User, users) user = User() Thanks --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Table updates using data mapping
On Jun 26, 2007, at 4:51 PM, Rick Morrison wrote:
Updates and inserts on the ORM side of the street are single-object
kinds of things. The pattern is to load a list of objects, make the
appropriate modifications to the those in-memory objects, and then
issue a session flush().
This type of bulk operation is best done with the SQL generation
portion of the library, like so (using an implicit bound connection
here):
users.update(users.c.group == contractor).execute({users.c.group
= consultant})
using the actual execution terminology i made up ! nice
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[sqlalchemy] Re: Table updates using data mapping
On 6/26/07, voltron [EMAIL PROTECTED] wrote: sess = create_session() allusers = sess.query(User).select() for user in allusers: user.group = contractor print x.name This adds the overhead of creating a Python object for every row. If you already have many of the objects in memory anyway or the overhead is too small to be noticeable, you can do it this way. Rick's way sends one small query to the database, which does it all internally. -- Mike Orr [EMAIL PROTECTED] --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
