Mongo Query Expression Language

Query Fields

class ommongo.query_expression.QueryField(type, parent=None)

elem_match(value)

This method does two things depending on the context:

1. In the context of a query expression it:

Creates a query expression to do an $elemMatch on the selected field. If the type of this field is a DocumentField the value can be either a QueryExpression using that Document’s fields OR you can use a dict for raw mongo.

See the mongo documentation for thorough treatment of elemMatch: http://docs.mongodb.org/manual/reference/operator/elemMatch/

2. In the context of choosing fields in a query.fields() expr:

Sets the field to use elemMatch, so only the matching elements of a list are used. See the mongo docs for more details: http://docs.mongodb.org/manual/reference/projection/elemMatch/

endswith(suffix, ignore_case=False, options=None)

A query to check if a field ends with a given suffix string

Example: session.query(Spell).filter(Spells.name.endswith("cadabra", ignore_case=True))

eq_(value)

Creates a query expression where this field == value

Note

The prefered usage is via an operator: User.name == value

exclude()

Use in a query.fields() expression to say this field should be excluded. The default of fields() is to include only fields which are specified. This allows retrieving of “every field except ‘foo’”.

exists(exists=True)

Create a MongoDB query to check if a field exists on a Document.

fields_expression

ge_(value)

Creates a query expression where this field >= value

Note

The prefered usage is via an operator: User.name >= value

get_absolute_name()

Returns the full dotted name of this field

get_type()

Returns the underlying ommongo.fields.Field

gt_(value)

Creates a query expression where this field > value

Note

The prefered usage is via an operator: User.name > value

in_(*values)

A query to check if this query field is one of the values in values. Produces a MongoDB $in expression.

le_(value)

Creates a query expression where this field <= value

Note

The prefered usage is via an operator: User.name <= value

lt_(value)

Creates a query expression where this field < value

Note

The prefered usage is via an operator: User.name < value

matched_index()

Represents the matched array index on a query with objects inside of a list. In the MongoDB docs, this is the $ operator

ne_(value)

Creates a query expression where this field != value

Note

The prefered usage is via an operator: User.name != value

near(x, y, max_distance=None)

Return documents near the given point

near_sphere(x, y, max_distance=None)

Return documents near the given point using sphere distances

nin(*values)

A query to check if this query field is not one of the values in values. Produces a MongoDB $nin expression.

regex(expression, ignore_case=False, options=None)

A query to check if a field matches a given regular expression :param ignore_case: Whether or not to ignore the case (setting this to True is the same as setting the ‘i’ option) :param options: A string of option characters, as per the MongoDB $regex operator (e.g. “imxs”)

Example: session.query(Spell).filter(Spells.name.regex(r'^abra[a-z]*cadabra$', ignore_case=True))

startswith(prefix, ignore_case=False, options=None)

A query to check if a field starts with a given prefix string

Example: session.query(Spell).filter(Spells.name.startswith("abra", ignore_case=True))

Note

This is a shortcut to .regex(‘^’ + re.escape(prefix)) MongoDB optimises such prefix expressions to use indexes appropriately. As the prefix contains no further regex, this will be optimized by matching only against the prefix.

within_box(corner1, corner2)

Adapted from the Mongo docs:

session.query(Places).filter(Places.loc.within_box(cornerA, cornerB)

within_polygon(polygon)

Adapted from the Mongo docs:

polygonA = [ [ 10, 20 ], [ 10, 40 ], [ 30, 40 ], [ 30, 20 ] ]
polygonB = { a : { x : 10, y : 20 }, b : { x : 15, y : 25 }, c : { x : 20, y : 20 } }
session.query(Places).filter(Places.loc.within_polygon(polygonA)
session.query(Places).filter(Places.loc.within_polygon(polygonB)

within_radius(x, y, radius)

Adapted from the Mongo docs:

session.query(Places).filter(Places.loc.within_radius(1, 2, 50)

within_radius_sphere(x, y, radius)

Adapted from the Mongo docs:

session.query(Places).filter(Places.loc.within_radius_sphere(1, 2, 50)

Query Expressions

class ommongo.query_expression.QueryExpression(obj)

A QueryExpression wraps a dictionary representing a query to perform on a mongo collection. The

Note

There is no and_ expression because multiple expressions can be specified to a single call of Query.filter()

not_()

Negates this instance’s query expression using MongoDB’s $not operator

Example: (User.name == 'Jeff').not_()

Note

Another usage is via an operator, but parens are needed to get past precedence issues: ~ (User.name == 'Jeff')

or_(expression)

Adds the given expression to this instance’s MongoDB $or expression, starting a new one if one does not exst

Example: (User.name == 'Jeff').or_(User.name == 'Jack')

Note

The prefered usageis via an operator: User.name == 'Jeff' | User.name == 'Jack'