Google App Engine Python Sdk
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2Google App Engine
Property
is the superclass for data model definitions.
Query
uses objects and methods to prepare queries.
Python SDK 1.2.2
REVISION 1.1 05.21.09
CONSTRUCTOR
CONSTRUCTOR
class Property(verbose_name=None, name=None,
Datastore
class Query(model_class)
google.appengine.ext.db
indexed=True, default=None, choices=None
A scalable storage and query engine.
INSTANCE METHODS
required=False, validator=None)
filter(property_operator, value)
self
CLASS ATTRIBUTES
PACKAGE FUNCTIONS
order(property)
self
data_type
get(key)
Model instance
ancestor(model_instance|key)
self
You can also pass multiple keys and it will return multiple Model instances.
INSTANCE METHODS
get()
model instance or None
default_value()
value
put(model_instance)
Key object
fetch(limit, offset=0)
list of model instances
You can also pass multiple model instances and it will return multiple keys.
validate(value)
value or exception
count(limit=None)
integer
empty(value)
bool
delete(model_instance|key)
Key
represents a unique key for a datastore entity.
TYPE AND PROPERTY CLASSES
run_in_transaction(function, *args, **kwargs)
run_in_transaction_custom_retries(retries, function,
CONSTRUCTOR
Property Class
Value Type
Sort Order
*args, **kwargs)
class Key(encoded=None)
StringProperty
str
Unicode (str is treated as ASCII)
unicode
Model
is the superclass for data model definitions.
CLASS METHODS
ByteStringProperty
db.ByteString
byte order
Key.from_path(*args, **kwds)
CONSTRUCTOR
BooleanProperty
bool
False < True
This example creates a key for an Address entity with the numeric ID 9876 whose par-
class Model(parent=None, key_name=None, **kwds)
ent is a User entity with the named key ‘Boris’:
IntegerProperty
int
Numeric
CLASS METHODS
long
k = Key.from_path(‘User’, ‘Boris’, ‘Address’, 9876)
get(key)
Key object
FloatProperty
float
Numeric
INSTANCE METHODS
get_by_id(id, parent=None)
Model instance
DateTimeProperty
datetime.datetime
Chronological
app()
Application name (string)
You can also pass multiple ids and it will return multiple Model instances.
DateProperty
kind()
Kind (string)
TimeProperty
get_by_key_name(key_name, parent=None)
see above
id()
Numeric ID (int)
ListProperty
list
If ascending, by least element; if
You can also pass multiple ids and it will return multiple Model instances.
StringListProperty
descending, by greatest element
name()
Entity name (string)
get_or_insert(key_name, **kwds)
see above
ReferenceProperty
db.Key
By path elements (kind, ID or name)
id_or_name()
Numeric ID(int) or name (string)
SelfReferenceProperty
all()
Query object
has_id_or_name()
bool
UserProperty
user.User
By email address
gql(query_string, *args, **kwds)
GQLQuery object
parent()
Key
BlobProperty
db.Blob
(not orderable)
Examples:
GQL
is a SQL-like language for retrieving entities.
TextProperty
db. T ext
(not orderable)
s = Story.gql(“WHERE title = :1”, “The Little Prince”)
SYNTAX
s = Story.gql(“WHERE title = :title”, title=”The Little Prince”)
CategoryProperty
db.Category
Unicode
WHERE <condition> [AND <condition> ...]
kind()
Kind
LinkProperty
db.Link
Unicode
ORDER BY <property> [ASC | DESC] [,<property> [ASC | DESC]…]
properties()
dict
LIMIT [<offset>,]<count>
EmailProperty
db.Email
Unicode
INSTANCE METHODS
OFFSET <offset>
GeoPtProperty
db.GeoPt
By latitude, then longitude
key()
Key
<condition> := <property> {< | <= | > | >= | = | != } <value>
put()
Key
<condition> := <property> IN <list>
IMProperty
db.IM
Unicode
<condition> := ANCESTOR IS <entity or key>
delete()
PhoneNumberProperty
db.PhoneNumber
Unicode
<list> := (<value>, …)
is_saved()
bool
PostalAddressProperty
db.PostalAddress
Unicode
Note that
and
are substitutions for positional and keyword argu-
:NUMBER
:NAME
parent()
Model
ments, referrring to
(starting at 1) and
respectively. See
*args
**kwds
RatingProperty
db.Rating
Unicode
parent_key()
Key
for example usage. Key-only queries are supported using either
Model.gql()
.
SELECT __key__
to_xml()
XML
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