This is where sqlalchemy gets murky for me. If I return all classes, I'm not returning all *instances* of those classes. How, then, would I update a given customer's record? The objects (c1 and c2, for instance) were instantiated elsewhere, and my GUIManager module has no knowledge of them. More generally, when I switch this over to our AS400 and start querying, I won't have created any records at all. Every record will be pulled from a table on the 400, and while I will have a schema, I won't have any instances of that schema.
As I think about this, it occurs to me that I should *create* the record objects from the records. That is: for record in recordsList: #an array of session.query(someTable).all() myTempRecord = mySchemaClass(record) myTempRecord.property = newValue #update the database Assuming GUIManager knows about mySchemaClass, would that approach work? How I'd pass in a record and get back an instance of mySchemaClass I'm not yet sure, but is this worth looking into more, or am I on the wrong track? On 2/4/16, Simon King <si...@simonking.org.uk> wrote: > getAllTables is returning Core Table objects. I suppose you could have a > similar function which returns all mapped classes, something like this: > > def getAllClasses(): > return base.__subclasses__() > > (If your class hierarchy is more complicated you'd need a more > sophisticated function there) > > Simon > > On Thu, Feb 4, 2016 at 12:32 PM, Alex Hall <ah...@autodist.com> wrote: > >> Yes, I'm using Declarative. I was following a great tutorial, then >> realized it was way out of date. The one recommended on the forum I >> found said to use Declarative, so I did. >> >> In DBInterface, I have this little function: >> >> def getAllTables(): >> return base.metadata.tables >> #end def getAllTables >> >> I then loop over that array, grabbing the value only and ignoring the >> key. I just tried printing the type, as in: >> >> def getAllTables(): >> for table in base.metadata.tables.values(): >> print type(table) >> return base.metadata.tables >> #end def getAllTables >> >> I got <class 'sqlalchemy.sql.schema.Table'> Here's the loop that >> generates the table list passed to my GUI (remember that this must be >> an array of arrays): >> >> tables = DBInterface.getAllTables() >> tablesList = [] >> for table in tables.values(): >> tablesList.append([table]) >> #end for >> >> Just to be sure, I stuck a "print type(table)" statement in that for >> loop, and the objects are still sqlalchemy.sql.schema.Table objects. >> >> On 2/4/16, Simon King <si...@simonking.org.uk> wrote: >> > SQLAlchemy has 2 main layers, the "Core" layer which deals with mostly >> > database-level constructs, such as Tables, and the ORM layer, which is >> > built on top of Core. With the ORM, you map your own classes onto the >> > lower-level Tables, then work with instances of those classes. You >> > appear >> > to be using the declarative system to define your classes, so >> > SQLAlchemy >> > will be creating the associated Table instances for you under the hood. >> > >> > In your example, Customer is an ORM-level class. Somewhere, there will >> be a >> > construct representing the Core-level Table that the Customer class is >> > mapped to. (It's probably available at Customer.__table__, but also in >> > other places). >> > >> > When you say that "self.choices" contains table objects, I suspect that >> > those are the Core-level Table instances. When you query using those, >> > you >> > don't get Customer objects back. You need to query using the Customer >> class >> > instead. Can you get the Customer class into your self.choices array, >> > either instead of the table, or as well as? Where are you getting the >> > object that you are putting in the first element of each of the >> > self.choices list? >> > >> > Simon >> > >> > On Thu, Feb 4, 2016 at 11:34 AM, Alex Hall <ah...@autodist.com> wrote: >> > >> >> It's all from a GUI, so it's something like this (my code isn't in >> >> front >> >> of me): >> >> DBInterface.session"query(self.choices[self.selectedIndex][0]).all() >> >> Choices is a 2D array where the first (0th) element of each sub-array >> >> is >> >> a >> >> table object. The query works, because I get the records as expected >> >> and >> >> can display them or inspect them. I just can't modify them for some >> >> reason. >> >> As I said, though, I'm new to this package so am likely missing an >> >> obvious >> >> step, or have something set up very wrong. >> >> >> >> Sent from my iPhone >> >> >> >> > On Feb 3, 2016, at 16:18, Simon King <si...@simonking.org.uk> wrote: >> >> > >> >> > OK, so you’re not actually getting Customer objects back from your >> >> query. What does your call to session.query() look like? For this to >> >> work, >> >> it really ought to be something like “session.query(Customer)”. I >> suspect >> >> you are doing something like “session.query(Customer.id, >> >> Customer.name, >> >> …)” >> >> instead. >> >> > >> >> > Simon >> >> > >> >> >> On 3 Feb 2016, at 17:43, Alex Hall <ah...@autodist.com> wrote: >> >> >> >> >> >> I'm on the Gmail site, so am not sure I can reply in-line. Sorry. >> >> >> >> >> >> This is a basic table class, like >> >> >> class Customer(base): >> >> >> __tablename__ = "customers" >> >> >> name = Column(String(50)), >> >> >> ... >> >> >> >> >> >> When I print the type: >> >> >> <class 'sqlalchemy.util._collections.result'> >> >> >> And repr(): >> >> >> (2, u'Powersports Etc', 5554443210L, u'ahall+dbte...@autodist.com', >> >> True) >> >> >> >> >> >> >> >> >>> On 2/3/16, Simon King <si...@simonking.org.uk> wrote: >> >> >>>> On Wed, Feb 3, 2016 at 3:54 PM, Alex Hall <ah...@autodist.com> >> >> >>>> wrote: >> >> >>>> >> >> >>>> Hello list, >> >> >>>> I'm new to SQLAlchemy, but not to Python. I have an application >> >> >>>> that's >> >> >>>> coming together, and relies on SQLAlchemy to talk to a database >> >> >>>> for >> >> >>>> many of the app's functions. Listing tables, listing records, >> >> >>>> updating >> >> >>>> records, pulling records for internal use, and so on. >> >> >>>> >> >> >>>> My app is working, but so far I've been writing the framework and >> >> >>>> GUI >> >> >>>> with a bit of SQLite just to check that things are working how I >> >> >>>> want. >> >> >>>> Now, though, I'm getting into my first "real" user-facing >> >> >>>> database >> >> >>>> task: taking the values from a dialog and updating a record >> >> >>>> according >> >> >>>> to those values. Thus far, I'm having no luck. >> >> >>>> >> >> >>>> My organization for now is DBInterface.py, which holds all my >> >> >>>> table >> >> >>>> definitions, database details, and my base, session, and engine >> >> >>>> objects. I can hear the groans from here; I do plan to move the >> >> >>>> table >> >> >>>> definitions into a module of their own at some point, there >> >> >>>> simply >> >> >>>> hasn't been a need yet. GUIManager.py imports DBInterface, and >> >> >>>> handles >> >> >>>> all the GUI stuff, as the name suggests. It's where, eventually, >> >> >>>> I'll >> >> >>>> take user input and use it to update records by calling functions >> >> >>>> from >> >> >>>> DBInterface. That's the problem, though. In GUIManager, I have a >> >> >>>> simple test: >> >> >>>> >> >> >>>> self.records[self.selectedRecordIndex].name="test name" #records >> >> >>>> is >> >> >>>> the list of objects returned by querying the current table >> >> >>>> >> >> >>>> Which errors out every time: >> >> >>>> AttributeError: can't set attribute >> >> >>>> >> >> >>>> (Yes, "name" is an attribute name of my Customer class.) From >> >> >>>> what >> >> >>>> I've read thus far, updating records is as easy as modifying >> >> >>>> their >> >> >>>> properties and calling session.commit(). That isn't working, >> though. >> >> >>>> I >> >> >>>> imagine the problem is that the records in a query aren't the >> >> >>>> same >> >> >>>> as >> >> >>>> the records originally created, and modify/commit only works on >> >> >>>> those >> >> >>>> originals. I'm not sure if that's right, though. If it is, how >> could >> >> >>>> I >> >> >>>> modify the originals, given that I run a new query each time the >> >> >>>> user >> >> >>>> selects a table name in my GUI's list of names? If I'm wrong, how >> >> >>>> would I update the record attributes and save the changes back to >> >> >>>> the >> >> >>>> database? I think I'm picturing this whole thing wrong, to be >> >> >>>> honest. >> >> >>>> Thanks for any help, and please let me know if I need to provide >> >> >>>> more >> >> >>>> code or context. >> >> >>> Is your query against a single mapped class, or is it against some >> >> >>> set >> >> of >> >> >>> columns? What do you get if you write: >> >> >>> >> >> >>> print type(self.records[self.selectedRecordIndex]) >> >> >>> print repr(self.records[self.selectedRecordIndex]) >> >> >>> >> >> >>> ...at the point where you are trying to set the name? >> >> >>> >> >> >>> Simon >> >> >>> >> >> >>> -- >> >> >>> You received this message because you are subscribed to the Google >> >> Groups >> >> >>> "sqlalchemy" group. >> >> >>> To unsubscribe from this group and stop receiving emails from it, >> >> >>> send >> >> an >> >> >>> email to sqlalchemy+unsubscr...@googlegroups.com. >> >> >>> To post to this group, send email to sqlalchemy@googlegroups.com. >> >> >>> Visit this group at https://groups.google.com/group/sqlalchemy. >> >> >>> For more options, visit https://groups.google.com/d/optout. >> >> >> >> >> >> -- >> >> >> You received this message because you are subscribed to the Google >> >> Groups "sqlalchemy" group. >> >> >> To unsubscribe from this group and stop receiving emails from it, >> send >> >> an email to sqlalchemy+unsubscr...@googlegroups.com. >> >> >> To post to this group, send email to sqlalchemy@googlegroups.com. >> >> >> Visit this group at https://groups.google.com/group/sqlalchemy. >> >> >> For more options, visit https://groups.google.com/d/optout. >> >> > >> >> > -- >> >> > You received this message because you are subscribed to the Google >> >> Groups "sqlalchemy" group. >> >> > To unsubscribe from this group and stop receiving emails from it, >> >> > send >> >> an email to sqlalchemy+unsubscr...@googlegroups.com. >> >> > To post to this group, send email to sqlalchemy@googlegroups.com. >> >> > Visit this group at https://groups.google.com/group/sqlalchemy. >> >> > For more options, visit https://groups.google.com/d/optout. >> >> >> >> -- >> >> You received this message because you are subscribed to the Google >> Groups >> >> "sqlalchemy" group. >> >> To unsubscribe from this group and stop receiving emails from it, send >> an >> >> email to sqlalchemy+unsubscr...@googlegroups.com. >> >> To post to this group, send email to sqlalchemy@googlegroups.com. >> >> Visit this group at https://groups.google.com/group/sqlalchemy. >> >> For more options, visit https://groups.google.com/d/optout. >> >> >> > >> > -- >> > You received this message because you are subscribed to the Google >> > Groups >> > "sqlalchemy" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> > an >> > email to sqlalchemy+unsubscr...@googlegroups.com. >> > To post to this group, send email to sqlalchemy@googlegroups.com. >> > Visit this group at https://groups.google.com/group/sqlalchemy. >> > For more options, visit https://groups.google.com/d/optout. >> > >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sqlalchemy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sqlalchemy+unsubscr...@googlegroups.com. >> To post to this group, send email to sqlalchemy@googlegroups.com. >> Visit this group at https://groups.google.com/group/sqlalchemy. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at https://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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