diff options
| -rw-r--r-- | doc/build/mappers.rst | 22 | ||||
| -rw-r--r-- | lib/sqlalchemy/databases/mssql.py | 2 | ||||
| -rw-r--r-- | lib/sqlalchemy/orm/session.py | 2 |
3 files changed, 22 insertions, 4 deletions
diff --git a/doc/build/mappers.rst b/doc/build/mappers.rst index 80fe8045a..bc0d59e31 100644 --- a/doc/build/mappers.rst +++ b/doc/build/mappers.rst @@ -1564,7 +1564,7 @@ It works just as well with an inline ``Query.join()`` or ``Query.outerjoin()``:: session.query(User).outerjoin(User.addresses).options(contains_eager(User.addresses)).all() -If the "eager" portion of the statement is "aliased", the ``alias`` keyword argument to ``contains_eager()`` may be used to indicate it. This is a string alias name or reference to an actual ``Alias`` object: +If the "eager" portion of the statement is "aliased", the ``alias`` keyword argument to ``contains_eager()`` may be used to indicate it. This is a string alias name or reference to an actual ``Alias`` (or other selectable) object: .. sourcecode:: python+sql @@ -1572,7 +1572,9 @@ If the "eager" portion of the statement is "aliased", the ``alias`` keyword argu adalias = aliased(Address) # construct a Query object which expects the "addresses" results - query = session.query(User).outerjoin((adalias, User.addresses)).options(contains_eager(User.addresses, alias=adalias)) + query = session.query(User).\ + outerjoin((adalias, User.addresses)).\ + options(contains_eager(User.addresses, alias=adalias)) # get results normally {sql}r = query.all() @@ -1580,6 +1582,22 @@ If the "eager" portion of the statement is "aliased", the ``alias`` keyword argu adalias.user_id AS adalias_user_id, adalias.email_address AS adalias_email_address, (...other columns...) FROM users LEFT OUTER JOIN email_addresses AS email_addresses_1 ON users.user_id = email_addresses_1.user_id +The ``alias`` argument is used only as a source of columns to match up to the result set. You can use it even to match up the result to arbitrary label names in a string SQL statement, by passing a selectable() which links those labels to the mapped ``Table``:: + + # label the columns of the addresses table + eager_columns = select([ + addresses.c.address_id.label('a1'), + addresses.c.email_address.label('a2'), + addresses.c.user_id.label('a3')]) + + # select from a raw SQL statement which uses those label names for the + # addresses table. contains_eager() matches them up. + query = session.query(User).\ + from_statement("select users.*, addresses.address_id as a1, " + "addresses.email_address as a2, addresses.user_id as a3 " + "from users left outer join addresses on users.user_id=addresses.user_id").\ + options(contains_eager(User.addresses, alias=eager_columns)) + The path given as the argument to ``contains_eager()`` needs to be a full path from the starting entity. For example if we were loading ``Users->orders->Order->items->Item``, the string version would look like:: query(User).options(contains_eager('orders', 'items')) diff --git a/lib/sqlalchemy/databases/mssql.py b/lib/sqlalchemy/databases/mssql.py index 4d2176f85..95be55e7f 100644 --- a/lib/sqlalchemy/databases/mssql.py +++ b/lib/sqlalchemy/databases/mssql.py @@ -96,7 +96,7 @@ arguments on the URL, or as keyword argument to * *auto_identity_insert* - enables support for IDENTITY inserts by automatically turning IDENTITY INSERT ON and OFF as required. - Defaults to ``True`. + Defaults to ``True``. * *query_timeout* - allows you to override the default query timeout. Defaults to ``None``. This is only supported on pymssql. diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py index 3be8dac39..b44ec25d5 100644 --- a/lib/sqlalchemy/orm/session.py +++ b/lib/sqlalchemy/orm/session.py @@ -742,7 +742,7 @@ class Session(object): Optional, a ``mapper`` or mapped class \**kw - Additional keyword arguments are sent to :method:`get_bind()` + Additional keyword arguments are sent to :meth:`get_bind()` which locates a connectable to use for the execution. Subclasses of :class:`Session` may override this. |