Re: [sqlalchemy] Relationship setup

Hey Michael, I really appreciate all that, it was extremely informative. For the academic sake I have this extrapolated to include all the actual intermediate tables that TableB would include. For the academic sake, without the mixin and proxy, given a traditional approach where TableA is

[sqlalchemy] Relationship setup

I have about a dozen tables with an id PK column and a single column with some unique string. I then have a single table that composes 13 rows with an id PK field and all FK refs to rows in the other 12 tables. Bulk inserting data into the initial 12 tables is simple but I am not certain how to

Re: [sqlalchemy] Relationship setup

Hey Michael, Lets say I have a table TableA: class TableA(Base): __tablename__ = 'table_a' id = Column(Integer, primary_key=True) name = Column(String(collation='nocase'), unique=True, nullable=False) Then TableB: class TableB(Base): __tablename__ = 'table_b' id =

Re: [sqlalchemy] Relationship setup

I don’t understand. Do you mean at the configuration level? e.g.: class TableB(Base): # … name = relationship(TableA) # “name_id” is auto created? Right, So when a person is adding rows to TableB, they have a few ways of doing it. 1. If they know or lookup the actual PK

[sqlalchemy] Triggers with sqlite

For a trigger template something like: trg_template = CREATE TRIGGER trg_foo_{0} AFTER {0} ON foo FOR EACH ROW BEGIN ... END; Why does the following not work to remove some redundant boiler plate code: for x in 'UPDATE', 'INSERT', 'DELETE': event.listen(

Re: [sqlalchemy] Triggers with sqlite

You've been bitten by a Python gotcha! http://docs.python-guide.org/en/latest/writing/gotchas/#late-binding-closures Ugh, thanks Simon, moment of careless haste in thinking about this. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To

[sqlalchemy] Improving a subquery

I have scenario where I have a TableA that contains rows with with an optional reference to TableB. That foreign key column in TableA has triggers and constraints enforcing either one null or many with unique references. When I query for rows I need to select either rows with a reference that

Re: [sqlalchemy] String aggregation

, at 2:16 PM, Joseph Casale jcas...@gmail.com wrote: While not utilizing newer methods, this produced the desired effect: query = self.session.query(func.group_concat(TableA.name.op(',')(literal_column('|'.\ join(TableB).\ filter(TableB.table_a_id == TableA.id).\ filter

Re: [sqlalchemy] Scalar sub query as literal column

Thanks Michael, jlc On Tue, Nov 26, 2013 at 9:34 PM, Michael Bayer mike...@zzzcomputing.comwrote: On Nov 26, 2013, at 7:45 AM, Joseph Casale jcas...@gmail.com wrote: I have a scalar sub query with a predicate that involves a table and column produced in the outer query, Company.id

[sqlalchemy] Scalar sub query as literal column

I have a scalar sub query with a predicate that involves a table and column produced in the outer query, Company.id for example. The only way I could include the query was to write it out literally and add it as a column with literal_column. query = session.query(Company, City, ...,

[sqlalchemy] Re: String aggregation

While not utilizing newer methods, this produced the desired effect: query = self.session.query(func.group_concat(TableA.name.op(',')(literal_column('|'.\ join(TableB).\ filter(TableB.table_a_id == TableA.id).\ filter(TableB.col == some_val).\ one() -- You received this

Re: [sqlalchemy] Listener for metadata.create_all() event

://docs.sqlalchemy.org/en/rel_0_9/core/events.html?highlight=after_create#sqlalchemy.events.DDLEvents.after_create On Nov 21, 2013, at 8:02 PM, Joseph Casale jcas...@gmail.com wrote: Is it possible to construct a listener for this event, such that once all DDL has been run, some custom DLL statement(s

[sqlalchemy] Join query syntax

I have some sqlite tables such as: CREATE TABLE table_a ( id INTEGER NOT NULL, table_b_id INTEGER NOT NULL, name VARCHAR, PRIMARY KEY (id), FOREIGN KEY(table_b_id) REFERENCES table_b (id) ON DELETE CASCADE ); CREATE TABLE table_b ( id INTEGER NOT NULL, table_c_id INTEGER NOT NULL, name VARCHAR,

[sqlalchemy] Filter options

I am trying to write a convenience wrapper something like: def wrapper(self, arg_a=None, arg_a=None): query = self.session.query(Table_A).\ filter(Table_A.col_a == arg_a, Table_A.col_b == arg_b).\ all() ... The actual query is much longer, none the

Re: [sqlalchemy] Filter options

On Sunday, November 24, 2013 3:44:32 PM UTC-7, Michael Bayer wrote conditonals? Yeah, the queries are just so long and with all the combinations of possible criteria it would get out of hand as I have about 6 optional arguments. Currently I leverage one filter method and use eval on formatted

[sqlalchemy] Listener for metadata.create_all() event

Is it possible to construct a listener for this event, such that once all DDL has been run, some custom DLL statement(s) could be run without tying these to a specific table for example? Something like what @event.listens_for(Engine, 'connect') does but, but only after create just before the

Re: [sqlalchemy] Occasional InvalidRequestError: Table 'xxx' is already defined for this MetaData instance.

Hi Michael, idm_rw.py is simply a class that is fed stdin and processes and returns the input via stdout. The sqlalchemy imports at the top are leveraged within the classes init method for configuration queries. There are two plugins like this, each one is invoked in a fresh process and loads the

[sqlalchemy] Receiving sqlalchemy.exc.InvalidRequestError: Table 'xxx' is already defined for this MetaData instance.

I have a module I wrote that seems to emit this error during import of some of its table classes when concurrency gets high. The application that uses this module fires up an interpreter session for each Python script that leverages the import. When not under load or importing manually at the

Re: [sqlalchemy] Occasional InvalidRequestError: Table 'xxx' is already defined for this MetaData instance.

in addition to the main application thread. On Oct 20, 2013, at 11:04 PM, Joseph Casale jcas...@gmail.com wrote: I have a module that is imported by several Python scripts run by an application that fires up a new interpreter session for each invocation. When not under load or running

Re: [sqlalchemy] Occasional InvalidRequestError: Table 'xxx' is already defined for this MetaData instance.

itself should occur before the application starts any threads in addition to the main application thread. On Oct 20, 2013, at 11:04 PM, Joseph Casale jcas...@gmail.com wrote: I have a module that is imported by several Python scripts run by an application that fires up a new interpreter

[sqlalchemy] Occasional InvalidRequestError: Table 'xxx' is already defined for this MetaData instance.

I have a module that is imported by several Python scripts run by an application that fires up a new interpreter session for each invocation. When not under load or running the code manually at the cli things work fine but once the concurrency raises and the application starts seeing some load it

[sqlalchemy] Adding a trigger

I have a module I import which has some table defs and global sessionmaker() instance. If the module is ran directly, it executes a create_all() to build a new db. I am trying to add a trigger DDL event listener: trg = DDL('...') event.listen( SomeName.__table__, 'after_create',

Re: [sqlalchemy] Adding a trigger

you need to pass a Python callable function (def or lambda, typically) to event.listen, which it will call when the event occurs. right now you're just running the execute() before the listen() is even called: event.listen(table, after_create, lambda *args: trg.execute(bind=engine))