Re: [sqlalchemy] Adding a relationship for specific rows based on foreign value

2017-06-19 Thread mike bayer 



On 06/19/2017 08:29 PM, Van Klaveren, Brian N. wrote:

Hi,

I want to represent a One to Many relationship with an additional default value 
that depends on a value in the foreign table.

I think what I want is something like the following:


class UserDatabase(Base):
 db_id = Column(Integer, primary_key=True)
 repo_id = Column(Integer, ForeignKey("UserDatabase.db_id"), nullable=True)
 name = Column(String(128))
 description = Column(Text)
 conn_host = Column(String(128))
 conn_port = Column(Integer)
 schemas = relationship("UserDatabaseSchema", lazy="dynamic")
 # Where is_default_schema == True
 default_schema = relationship("UserDatabaseSchema", primaryjoin=???, 
lazy="dynamic")

class UserDatabaseSchema(Base):
 schema_id = Column(Integer, primary_key=True)
 db_id = Column(Integer, ForeignKey("UserDatabase.db_id"))
 name = Column(String(128))
 description = Column(Text)
 is_default_schema = Column(Boolean)


but I'm not sure if primaryjoin is the proper argument for relationship and, if 
it is, what the expression should be. Or is this something that's best handled 
a different way?



you'd use primaryjoin for that and for examples see 
http://docs.sqlalchemy.org/en/rel_1_1/orm/join_conditions.html#specifying-alternate-join-conditions






Thanks,
Brian



--
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper


http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
--- 
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.

[sqlalchemy] Adding a relationship for specific rows based on foreign value

2017-06-19 Thread Van Klaveren, Brian N. 
Hi,

I want to represent a One to Many relationship with an additional default value 
that depends on a value in the foreign table.

I think what I want is something like the following:


class UserDatabase(Base):
db_id = Column(Integer, primary_key=True)
repo_id = Column(Integer, ForeignKey("UserDatabase.db_id"), nullable=True)
name = Column(String(128))
description = Column(Text)
conn_host = Column(String(128))
conn_port = Column(Integer)
schemas = relationship("UserDatabaseSchema", lazy="dynamic")
# Where is_default_schema == True
default_schema = relationship("UserDatabaseSchema", primaryjoin=???, 
lazy="dynamic")

class UserDatabaseSchema(Base):
schema_id = Column(Integer, primary_key=True)
db_id = Column(Integer, ForeignKey("UserDatabase.db_id"))
name = Column(String(128))
description = Column(Text)
is_default_schema = Column(Boolean)


but I'm not sure if primaryjoin is the proper argument for relationship and, if 
it is, what the expression should be. Or is this something that's best handled 
a different way?


Thanks,
Brian

-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
--- 
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.