google.appengine.datastore.datastore_query.Order

A base class that represents a sort order on a query.

Inherits From: expected_type

All sub-classes must be immutable as these are often stored without creating a defensive copying.

This class can be used as either the cmp or key arg in sorted() or list.sort(). To provide a stable ordering a trailing key ascending order is always used.

Methods

cmp

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cmp(
    lhs, rhs, filter_predicate=None
)

Compares the given values taking into account any filters.

This function can be used as the cmp argument for list.sort() and sorted().

This function is slightly more efficient that Order.key when comparing two entities, however it is much less efficient when sorting a list of entities.

Args
lhs	An entity_pb2.EntityProto
rhs	An entity_pb2.EntityProto
filter_predicate	A FilterPredicate used to prune values before comparing entities or None.

Returns
An integer <, = or > 0 representing the operator that goes in between lhs and rhs that to create a true statement.

cmp_for_filter

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cmp_for_filter(
    filter_predicate
)

key

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key(
    entity, filter_predicate=None
)

Constructs a "key" value for the given entity based on the current order.

This function can be used as the key argument for list.sort() and sorted().

Args
entity	The entity_pb2.EntityProto to convert
filter_predicate	A FilterPredicate used to prune values before comparing entities or None.

Returns
A key value that identifies the position of the entity when sorted by the current order.

key_for_filter

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key_for_filter(
    filter_predicate
)

reversed

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reversed(
    group_by=None
)

Constructs an order representing the reverse of the current order.

This function takes into account the effects of orders on properties not in the group_by clause of a query. For example, consider: SELECT A, First(B) ... GROUP BY A ORDER BY A, B Changing the order of B would effect which value is listed in the 'First(B)' column which would actually change the results instead of just reversing them.

Args
group_by	If specified, only orders on properties in group_by will be reversed.

Returns
A new order representing the reverse direction.

__eq__

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__eq__(
    other
)

Return self==value.

__ne__

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__ne__(
    other
)

Return self!=value.