Entity properties

Entities are a collection of Properties of different types. These classes implement the default set of types used in endpoints.

At entity class level, these properties are used in querying entities:

>>> import datetime
>>> Order.ShippedDate > datetime.datetime.now()
'ShippedDate gt 2016-02-19T12:02:04.956226'
>>> Service.query(Order).filter(Order.OrderID == 1234)

Once the entity is instanced, the properties act as data getters and setters:

>>> order = Order()
>>> order.ShippedDate = datetime.datetime.now()
>>> Service.save(order)

Setting a new value to a property marks the property as dirty, and will be sent to the endpoint when save() is called.

This behavior is similar to SQLAlchemy’s ORM.

Navigation properties

The entity can define properties that link to other entities. These are known as navigation properties and are supported in this library.

>>> order = Service.query(Order).first()
>>> order.Shipper
<Entity(Shipper:3)>
>>> order.Shipper.CompanyName
'Federal Shipping'

When creating new instances, relationships can be assigned via navigation properties:

# query a shipper instance, just for this example
Shipper = Service.entities['Shipper']
my_shipper = Service.query(Shipper).first()

# assign for the new Order
order.Shipper = my_shipper
Service.save(order)

Creating new property types

All properties must subclass PropertyBase, and implement the serialization methods. You can then use the created Property class in your custom defined entities. Replacing the default types is not supported.

class odata.property.PropertyBase(name, primary_key=False, is_collection=False, is_computed_value=False)

A base class for all properties.

Parameters:

• name – Name of the property in the endpoint
• primary_key – This property is a primary key
• is_collection – This property contains multiple values

deserialize(value)

Called when deserializing the value from JSON to Python. Implement this method when creating a new Property class

Parameters:value – Value received in JSON Returns:Value that will be passed to Python

escape_value(value)

Called when escaping the property value for usage in Query string. Implement this method when creating a new Property class

Parameters:value – Value of this property Returns:Escaped value that can be used in Query string

serialize(value)

Called when serializing the value to JSON. Implement this method when creating a new Property class

Parameters:value – Value given in Python code Returns:Value that will be used in JSON

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Types

class odata.property.BooleanProperty(name, primary_key=False, is_collection=False, is_computed_value=False)

Property that stores a boolean value

class odata.property.DatetimeProperty(name, primary_key=False, is_collection=False, is_computed_value=False)

Property that stores a datetime object. JSON does not support date objects natively so dates are transmitted as ISO-8601 formatted strings

class odata.property.DecimalProperty(name, primary_key=False, is_collection=False, is_computed_value=False)

Property that stores a decimal value. JSON does not support this directly, so the value will be transmitted as a float

class odata.property.FloatProperty(name, primary_key=False, is_collection=False, is_computed_value=False)

Property that stores a float value

class odata.property.IntegerProperty(name, primary_key=False, is_collection=False, is_computed_value=False)

Property that stores a plain old integer

class odata.property.StringProperty(name, primary_key=False, is_collection=False, is_computed_value=False)

Property that stores a unicode string

class odata.property.UUIDProperty(name, primary_key=False, is_collection=False, is_computed_value=False)

Property that stores a UUID (also known as GUID) value. JSON does not support this directly, so the value will be transmitted as a string. Unlike StringProperty, it does not escape quotes as query filters do not use quotes for UUID