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| -rw-r--r-- | doc/build/mappers.rst | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/doc/build/mappers.rst b/doc/build/mappers.rst index bc0d59e31..138c530d4 100644 --- a/doc/build/mappers.rst +++ b/doc/build/mappers.rst @@ -658,7 +658,7 @@ Upon select, the polymorphic union produces a query like this: Using Relations with Inheritance ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Both joined-table and single table inheritance scenarios produce mappings which are usable in relation() functions; that is, it's possible to map a parent object to a child object which is polymorphic. Similarly, inheriting mappers can have ``relation()``s of their own at any level, which are inherited to each child class. The only requirement for relations is that there is a table relationship between parent and child. An example is the following modification to the joined table inheritance example, which sets a bi-directional relationship between ``Employee`` and ``Company``: +Both joined-table and single table inheritance scenarios produce mappings which are usable in relation() functions; that is, it's possible to map a parent object to a child object which is polymorphic. Similarly, inheriting mappers can have ``relation()`` objects of their own at any level, which are inherited to each child class. The only requirement for relations is that there is a table relationship between parent and child. An example is the following modification to the joined table inheritance example, which sets a bi-directional relationship between ``Employee`` and ``Company``: .. sourcecode:: python+sql @@ -804,7 +804,7 @@ Multiple Mappers for One Class ------------------------------- -The first mapper created for a certain class is known as that class's "primary mapper." Other mappers can be created as well on the "load side" - these are called **secondary mappers**. This is a mapper that must be constructed with the keyword argument ``non_primary=True``, and represents a load-only mapper. Objects that are loaded with a secondary mapper will have their save operation processed by the primary mapper. It is also invalid to add new ``relation()``s to a non-primary mapper. To use this mapper with the Session, specify it to the ``query`` method: +The first mapper created for a certain class is known as that class's "primary mapper." Other mappers can be created as well on the "load side" - these are called **secondary mappers**. This is a mapper that must be constructed with the keyword argument ``non_primary=True``, and represents a load-only mapper. Objects that are loaded with a secondary mapper will have their save operation processed by the primary mapper. It is also invalid to add new ``relation()`` objects to a non-primary mapper. To use this mapper with the Session, specify it to the ``query`` method: example: |