The Database Layer

The manila.db.api Module

Defines interface for DB access.

The underlying driver is loaded as a LazyPluggable.

Functions in this module are imported into the manila.db namespace. Call these functions from manila.db namespace, not the manila.db.api namespace.

All functions in this module return objects that implement a dictionary-like interface. Currently, many of these objects are sqlalchemy objects that implement a dictionary interface. However, a future goal is to have all of these objects be simple dictionaries.

Related Flags

backend:string to lookup in the list of LazyPluggable backends. sqlalchemy is the only supported backend right now. connection:string specifying the sqlalchemy connection to use, like: sqlite:///var/lib/manila/manila.sqlite. enable_new_services:  when adding a new service to the database, is it in the pool of available hardware (Default: True)

network_allocation_create(context, values)

Create a network allocation DB record.

network_allocation_delete(context, id)

Delete a network allocation DB record.

network_allocation_update(context, id, values)

Update a network allocation DB record.

network_allocations_get_for_share_server(context, share_server_id, session=None)

Get netwwork allocation for share server.

quota_class_create(context, class_name, resource, limit)

Create a quota class for the given name and resource.

quota_class_get(context, class_name, resource)

Retrieve a quota class or raise if it does not exist.

quota_class_get_all_by_name(context, class_name)

Retrieve all quotas associated with a given quota class.

quota_class_get_default(context)

Retrieve all default quotas.

quota_class_update(context, class_name, resource, limit)

Update a quota class or raise if it does not exist.

quota_create(context, project_id, resource, limit, user_id=None)

Create a quota for the given project and resource.

quota_destroy_all_by_project(context, project_id)

Destroy all quotas associated with a given project.

quota_destroy_all_by_project_and_user(context, project_id, user_id)

Destroy all quotas associated with a given project and user.

quota_get(context, project_id, resource, user_id=None)

Retrieve a quota or raise if it does not exist.

quota_get_all(context, project_id)

Retrieve all user quotas associated with a given project.

quota_get_all_by_project(context, project_id)

Retrieve all quotas associated with a given project.

quota_get_all_by_project_and_user(context, project_id, user_id)

Retrieve all quotas associated with a given project and user.

quota_reserve(context, resources, quotas, user_quotas, deltas, expire, until_refresh, max_age, project_id=None, user_id=None)

Check quotas and create appropriate reservations.

quota_update(context, project_id, resource, limit, user_id=None)

Update a quota or raise if it does not exist.

quota_usage_get(context, project_id, resource, user_id=None)

Retrieve a quota usage or raise if it does not exist.

quota_usage_get_all_by_project(context, project_id)

Retrieve all usage associated with a given resource.

quota_usage_get_all_by_project_and_user(context, project_id, user_id)

Retrieve all usage associated with a given resource.

quota_usage_update(context, project_id, user_id, resource, **kwargs)

Update a quota usage or raise if it does not exist.

reservation_commit(context, reservations, project_id=None, user_id=None)

Commit quota reservations.

reservation_create(context, uuid, usage, project_id, user_id, resource, delta, expire)

Create a reservation for the given project and resource.

reservation_expire(context)

Roll back any expired reservations.

reservation_get(context, uuid)

Retrieve a reservation or raise if it does not exist.

reservation_rollback(context, reservations, project_id=None, user_id=None)

Roll back quota reservations.

security_service_create(context, values)

Create security service DB record.

security_service_delete(context, id)

Delete security service DB record.

security_service_get(context, id)

Get security service DB record.

security_service_get_all(context)

Get all security service DB records.

security_service_get_all_by_project(context, project_id)

Get all security service DB records for the given project.

security_service_update(context, id, values)

Update security service DB record.

service_create(context, values)

Create a service from the values dictionary.

service_destroy(context, service_id)

Destroy the service or raise if it does not exist.

service_get(context, service_id)

Get a service or raise if it does not exist.

service_get_all(context, disabled=None)

Get all services.

service_get_all_by_host(context, host)

Get all services for a given host.

service_get_all_by_topic(context, topic)

Get all services for a given topic.

service_get_all_share_sorted(context)

Get all share services sorted by share count.

Returns:a list of (Service, share_count) tuples.

service_get_by_args(context, host, binary)

Get the state of an service by node name and binary.

service_get_by_host_and_topic(context, host, topic)

Get a service by host it’s on and topic it listens to.

service_update(context, service_id, values)

Set the given properties on an service and update it.

Raises NotFound if service does not exist.

share_access_create(context, values)

Allow access to share.

share_access_delete(context, access_id)

Deny access to share.

share_access_get(context, access_id)

Allow access to share.

share_access_get_all_by_type_and_access(context, share_id, access_type, access)

Returns share access by given type and access.

share_access_get_all_for_share(context, share_id)

Allow access to share.

share_access_update(context, access_id, values)

Update access record.

share_create(context, values)

Create new share.

share_data_get_for_project(context, project_id, session=None)

Get (share_count, gigabytes) for project.

share_delete(context, share_id)

Delete share.

share_get(context, share_id)

Get share by id.

share_get_all(context)

Get all shares.

share_get_all_by_host(context, host)

Returns all shares with given host.

share_get_all_by_project(context, project_id)

Returns all shares with given project ID.

share_get_all_by_share_server(context, share_server_id)

Returns all shares with given share server.

share_metadata_delete(context, share_id, key)

Delete the given metadata item.

share_metadata_get(context, share_id)

Get all metadata for a share.

share_metadata_update(context, share, metadata, delete)

Update metadata if it exists, otherwise create it.

share_network_add_security_service(context, id, security_service_id)

share_network_create(context, values)

Create a share network DB record.

share_network_delete(context, id)

Delete a share network DB record.

share_network_get(context, id)

Get requested share network DB record.

share_network_get_all(context)

Get all share network DB records.

share_network_get_all_by_project(context, project_id)

Get all share network DB records for the given project.

share_network_get_all_by_security_service(context, share_network_id)

Get all share network DB records for the given project.

share_network_remove_security_service(context, id, security_service_id)

share_network_update(context, id, values)

Update a share network DB record.

share_server_backend_details_get(context, share_server_id)

Get all backend details records for share server.

share_server_backend_details_set(context, share_server_id, server_details)

Create DB record with backend details.

share_server_create(context, values)

Create share server DB record.

share_server_delete(context, id)

Delete share server DB record.

share_server_get(context, id, session=None)

Get share server DB record by ID.

share_server_get_all(context)

Get all share server DB records.

share_server_get_by_host(context, host, share_net_id, session=None)

Get share server DB records by host.

share_server_get_by_host_and_share_net(context, host, share_net_id, session=None)

Get share server DB records by host and share net.

share_server_get_by_host_and_share_net_valid(context, host, share_net_id, session=None)

Get share server DB records by host and share net not error.

share_server_update(context, id, values)

Update share server DB record.

share_snapshot_create(context, values)

Create a snapshot from the values dictionary.

share_snapshot_data_get_for_project(context, project_id, session=None)

Get count and gigabytes used for snapshots for specified project.

share_snapshot_destroy(context, snapshot_id)

Destroy the snapshot or raise if it does not exist.

share_snapshot_get(context, snapshot_id)

Get a snapshot or raise if it does not exist.

share_snapshot_get_all(context)

Get all snapshots.

share_snapshot_get_all_by_project(context, project_id)

Get all snapshots belonging to a project.

share_snapshot_get_all_for_share(context, share_id)

Get all snapshots for a share.

share_snapshot_update(context, snapshot_id, values)

Set the given properties on an snapshot and update it.

Raises NotFound if snapshot does not exist.

share_update(context, share_id, values)

Update share fields.

snapshot_data_get_for_project(context, project_id, session=None)

Get (snapshot_count, gigabytes) for project.

volume_get_active_by_window(context, begin, end=None, project_id=None)

Get all the volumes inside the window.

Specifying a project_id will filter for a certain project.

volume_type_create(context, values)

Create a new volume type.

volume_type_destroy(context, id)

Delete a volume type.

volume_type_extra_specs_delete(context, volume_type_id, key)

Delete the given extra specs item.

volume_type_extra_specs_get(context, volume_type_id)

Get all extra specs for a volume type.

volume_type_extra_specs_update_or_create(context, volume_type_id, extra_specs)

Create or update volume type extra specs.

This adds or modifies the key/value pairs specified in the extra specs dict argument.

volume_type_get(context, id, inactive=False)

Get volume type by id.

volume_type_get_all(context, inactive=False)

Get all volume types.

volume_type_get_by_name(context, name)

Get volume type by name.

volume_type_qos_specs_get(context, type_id)

Get all qos specs for given volume type.

The Sqlalchemy Driver

The manila.db.sqlalchemy.api Module

Implementation of SQLAlchemy backend.

The manila.db.sqlalchemy.models Module

SQLAlchemy models for Manila data.

class ManilaBase

Bases: oslo.db.sqlalchemy.models.ModelBase, oslo.db.sqlalchemy.models.TimestampMixin

Base class for Manila Models.

delete(session=None)

Delete this object.

deleted = Column(None, Integer(), table=None, default=ColumnDefault(0))

deleted_at = Column(None, DateTime(), table=None)

metadata = None

to_dict()

class ManilaNode(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a running manila service on a host.

created_at

deleted

deleted_at

id

service_id

updated_at

class NetworkAllocation(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents network allocation data.

created_at

deleted

deleted_at

id

ip_address

mac_address

share_server_id

status

updated_at

class ProjectUserQuota(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a single quota override for a user with in a project.

created_at

deleted

deleted_at

hard_limit

id

project_id

resource

updated_at

user_id

class Quota(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a single quota override for a project.

If there is no row for a given project id and resource, then the default for the quota class is used. If there is no row for a given quota class and resource, then the default for the deployment is used. If the row is present but the hard limit is Null, then the resource is unlimited.

created_at

deleted

deleted_at

hard_limit

id

project_id

resource

updated_at

class QuotaClass(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a single quota override for a quota class.

If there is no row for a given quota class and resource, then the default for the deployment is used. If the row is present but the hard limit is Null, then the resource is unlimited.

class_name

created_at

deleted

deleted_at

hard_limit

id

resource

updated_at

class QuotaUsage(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents the current usage for a given resource.

created_at

deleted

deleted_at

id

in_use

project_id

reserved

resource

total

until_refresh

updated_at

user_id

class Reservation(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a resource reservation for quotas.

created_at

deleted

deleted_at

delta

expire

id

project_id

resource

updated_at

usage_id

user_id

uuid

class SecurityService(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Security service information for manila shares.

created_at

deleted

deleted_at

description

dns_ip

domain

id

name

password

project_id

server

status

type

updated_at

user

class Service(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a running service on a host.

availability_zone

binary

created_at

deleted

deleted_at

disabled

host

id

report_count

topic

updated_at

class Share(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents an NFS and CIFS shares.

availability_zone

created_at

deleted

deleted_at

display_description

display_name

export_location

host

id

launched_at

name

project_id

scheduled_at

share_network_id

share_proto

share_server_id

size

snapshot_id

status

terminated_at

updated_at

user_id

volume_type_id

class ShareAccessMapping(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents access to NFS.

STATE_ACTIVE = 'active'

STATE_DELETED = 'deleted'

STATE_DELETING = 'deleting'

STATE_ERROR = 'error'

STATE_NEW = 'new'

access_to

access_type

created_at

deleted

deleted_at

id

share_id

state

updated_at

class ShareMetadata(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a metadata key/value pair for a share.

created_at

deleted

deleted_at

id

key

share

share_id

updated_at

value

class ShareNetwork(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents network data used by share.

cidr

created_at

deleted

deleted_at

description

id

ip_version

name

network_type

neutron_net_id

neutron_subnet_id

project_id

security_services

segmentation_id

share_servers

shares

updated_at

user_id

class ShareNetworkSecurityServiceAssociation(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Association table between compute_zones and compute_nodes tables.

created_at

deleted

deleted_at

id

security_service_id

share_network_id

updated_at

class ShareServer(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents share server used by share.

created_at

deleted

deleted_at

host

id

network_allocations

share_network_id

shares

status

updated_at

class ShareServerBackendDetails(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a metadata key/value pair for a share server.

created_at

deleted

deleted_at

id

key

share_server_id

updated_at

value

class ShareSnapshot(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents a snapshot of a share.

created_at

deleted

deleted_at

display_description

display_name

export_location

id

name

progress

project_id

share

share_id

share_name

share_proto

share_size

size

status

updated_at

user_id

class VolumeTypeExtraSpecs(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represents additional specs as key/value pairs for a volume_type.

created_at

deleted

deleted_at

id

key

updated_at

value

volume_type

volume_type_id

class VolumeTypes(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, manila.db.sqlalchemy.models.ManilaBase

Represent possible volume_types of volumes offered.

created_at

deleted

deleted_at

id

name

shares

updated_at

register_models()

Register Models and create metadata.

Called from manila.db.sqlalchemy.__init__ as part of loading the driver, it will never need to be called explicitly elsewhere unless the connection is lost and needs to be reestablished.

relationship(argument, secondary=None, primaryjoin=None, secondaryjoin=None, foreign_keys=None, uselist=None, order_by=False, backref=None, back_populates=None, post_update=False, cascade=False, extension=None, viewonly=False, lazy=True, collection_class=None, passive_deletes=False, passive_updates=True, remote_side=None, enable_typechecks=True, join_depth=None, comparator_factory=None, single_parent=False, innerjoin=False, distinct_target_key=None, doc=None, active_history=False, cascade_backrefs=True, load_on_pending=False, strategy_class=None, _local_remote_pairs=None, query_class=None, info=None)

Provide a relationship between two mapped classes.

This corresponds to a parent-child or associative table relationship. The constructed class is an instance of RelationshipProperty.

A typical relationship(), used in a classical mapping:

mapper(Parent, properties={
  'children': relationship(Child)
})

Some arguments accepted by relationship() optionally accept a callable function, which when called produces the desired value. The callable is invoked by the parent Mapper at “mapper initialization” time, which happens only when mappers are first used, and is assumed to be after all mappings have been constructed. This can be used to resolve order-of-declaration and other dependency issues, such as if Child is declared below Parent in the same file:

mapper(Parent, properties={
    "children":relationship(lambda: Child,
                        order_by=lambda: Child.id)
})

When using the declarative_toplevel extension, the Declarative initializer allows string arguments to be passed to relationship(). These string arguments are converted into callables that evaluate the string as Python code, using the Declarative class-registry as a namespace. This allows the lookup of related classes to be automatic via their string name, and removes the need to import related classes at all into the local module space:

from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class Parent(Base):
    __tablename__ = 'parent'
    id = Column(Integer, primary_key=True)
    children = relationship("Child", order_by="Child.id")

See also

relationship_config_toplevel - Full introductory and reference documentation for relationship().

orm_tutorial_relationship - ORM tutorial introduction.

Parameters:

• argument –

  a mapped class, or actual Mapper instance, representing the target of the relationship.

  :paramref:`~.relationship.argument` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

  See also

  declarative_configuring_relationships - further detail on relationship configuration when using Declarative.

• secondary –

  for a many-to-many relationship, specifies the intermediary table, and is typically an instance of Table. In less common circumstances, the argument may also be specified as an Alias construct, or even a Join construct.

  :paramref:`~.relationship.secondary` may also be passed as a callable function which is evaluated at mapper initialization time. When using Declarative, it may also be a string argument noting the name of a Table that is present in the MetaData collection associated with the parent-mapped Table.

  The :paramref:`~.relationship.secondary` keyword argument is typically applied in the case where the intermediary Table is not otherwise exprssed in any direct class mapping. If the “secondary” table is also explicitly mapped elsewhere (e.g. as in association_pattern), one should consider applying the :paramref:`~.relationship.viewonly` flag so that this relationship() is not used for persistence operations which may conflict with those of the association object pattern.

  See also

  relationships_many_to_many - Reference example of “many to many”.

  orm_tutorial_many_to_many - ORM tutorial introduction to many-to-many relationships.

  self_referential_many_to_many - Specifics on using many-to-many in a self-referential case.

  declarative_many_to_many - Additional options when using Declarative.

  association_pattern - an alternative to :paramref:`~.relationship.secondary` when composing association table relationships, allowing additional attributes to be specified on the association table.

  composite_secondary_join - a lesser-used pattern which in some cases can enable complex relationship() SQL conditions to be used.

  New in version 0.9.2: :paramref:`~.relationship.secondary` works more effectively when referring to a Join instance.

• active_history=False – When True, indicates that the “previous” value for a many-to-one reference should be loaded when replaced, if not already loaded. Normally, history tracking logic for simple many-to-ones only needs to be aware of the “new” value in order to perform a flush. This flag is available for applications that make use of attributes.get_history() which also need to know the “previous” value of the attribute.
• backref –

  indicates the string name of a property to be placed on the related mapper’s class that will handle this relationship in the other direction. The other property will be created automatically when the mappers are configured. Can also be passed as a backref() object to control the configuration of the new relationship.

  See also

  relationships_backref - Introductory documentation and examples.

  :paramref:`~.relationship.back_populates` - alternative form of backref specification.

  backref() - allows control over relationship() configuration when using :paramref:`~.relationship.backref`.

• back_populates –

  Takes a string name and has the same meaning as :paramref:`~.relationship.backref`, except the complementing property is not created automatically, and instead must be configured explicitly on the other mapper. The complementing property should also indicate :paramref:`~.relationship.back_populates` to this relationship to ensure proper functioning.

  See also

  relationships_backref - Introductory documentation and examples.

  :paramref:`~.relationship.backref` - alternative form of backref specification.

• cascade –

  a comma-separated list of cascade rules which determines how Session operations should be “cascaded” from parent to child. This defaults to False, which means the default cascade should be used - this default cascade is "save-update, merge".

  The available cascades are save-update, merge, expunge, delete, delete-orphan, and refresh-expire. An additional option, all indicates shorthand for "save-update, merge, refresh-expire, expunge, delete", and is often used as in "all, delete-orphan" to indicate that related objects should follow along with the parent object in all cases, and be deleted when de-associated.

  See also

  unitofwork_cascades - Full detail on each of the available cascade options.

  tutorial_delete_cascade - Tutorial example describing a delete cascade.

• cascade_backrefs=True –

  a boolean value indicating if the save-update cascade should operate along an assignment event intercepted by a backref. When set to False, the attribute managed by this relationship will not cascade an incoming transient object into the session of a persistent parent, if the event is received via backref.

  See also

  backref_cascade - Full discussion and examples on how the :paramref:`~.relationship.cascade_backrefs` option is used.

• collection_class –

  a class or callable that returns a new list-holding object. will be used in place of a plain list for storing elements.

  See also

  custom_collections - Introductory documentation and examples.

• comparator_factory –

  a class which extends RelationshipProperty.Comparator which provides custom SQL clause generation for comparison operations.

  See also

  PropComparator - some detail on redefining comparators at this level.

  custom_comparators - Brief intro to this feature.

• distinct_target_key=None –

  Indicate if a “subquery” eager load should apply the DISTINCT keyword to the innermost SELECT statement. When left as None, the DISTINCT keyword will be applied in those cases when the target columns do not comprise the full primary key of the target table. When set to True, the DISTINCT keyword is applied to the innermost SELECT unconditionally.

  It may be desirable to set this flag to False when the DISTINCT is reducing performance of the innermost subquery beyond that of what duplicate innermost rows may be causing.

  New in version 0.8.3: - :paramref:`~.relationship.distinct_target_key` allows the subquery eager loader to apply a DISTINCT modifier to the innermost SELECT.

  Changed in version 0.9.0: - :paramref:`~.relationship.distinct_target_key` now defaults to None, so that the feature enables itself automatically for those cases where the innermost query targets a non-unique key.

  See also

  loading_toplevel - includes an introduction to subquery eager loading.

• doc – docstring which will be applied to the resulting descriptor.
• extension –

  an AttributeExtension instance, or list of extensions, which will be prepended to the list of attribute listeners for the resulting descriptor placed on the class.

  Deprecated since version 0.7: Please see AttributeEvents.

• foreign_keys –

  a list of columns which are to be used as “foreign key” columns, or columns which refer to the value in a remote column, within the context of this relationship() object’s :paramref:`~.relationship.primaryjoin` condition. That is, if the :paramref:`~.relationship.primaryjoin` condition of this relationship() is a.id == b.a_id, and the values in b.a_id are required to be present in a.id, then the “foreign key” column of this relationship() is b.a_id.

  In normal cases, the :paramref:`~.relationship.foreign_keys` parameter is not required. relationship() will automatically determine which columns in the :paramref:`~.relationship.primaryjoin` conditition are to be considered “foreign key” columns based on those Column objects that specify ForeignKey, or are otherwise listed as referencing columns in a ForeignKeyConstraint construct. :paramref:`~.relationship.foreign_keys` is only needed when:

  1. There is more than one way to construct a join from the local table to the remote table, as there are multiple foreign key references present. Setting foreign_keys will limit the relationship() to consider just those columns specified here as “foreign”.

     Changed in version 0.8: A multiple-foreign key join ambiguity can be resolved by setting the :paramref:`~.relationship.foreign_keys` parameter alone, without the need to explicitly set :paramref:`~.relationship.primaryjoin` as well.

  2. The Table being mapped does not actually have ForeignKey or ForeignKeyConstraint constructs present, often because the table was reflected from a database that does not support foreign key reflection (MySQL MyISAM).
  3. The :paramref:`~.relationship.primaryjoin` argument is used to construct a non-standard join condition, which makes use of columns or expressions that do not normally refer to their “parent” column, such as a join condition expressed by a complex comparison using a SQL function.

  The relationship() construct will raise informative error messages that suggest the use of the :paramref:`~.relationship.foreign_keys` parameter when presented with an ambiguous condition. In typical cases, if relationship() doesn’t raise any exceptions, the :paramref:`~.relationship.foreign_keys` parameter is usually not needed.

  :paramref:`~.relationship.foreign_keys` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

  See also

  relationship_foreign_keys

  relationship_custom_foreign

  foreign() - allows direct annotation of the “foreign” columns within a :paramref:`~.relationship.primaryjoin` condition.

  New in version 0.8: The foreign() annotation can also be applied directly to the :paramref:`~.relationship.primaryjoin` expression, which is an alternate, more specific system of describing which columns in a particular :paramref:`~.relationship.primaryjoin` should be considered “foreign”.

• info –

  Optional data dictionary which will be populated into the MapperProperty.info attribute of this object.

  New in version 0.8.

• innerjoin=False –

  when True, joined eager loads will use an inner join to join against related tables instead of an outer join. The purpose of this option is generally one of performance, as inner joins generally perform better than outer joins.

  This flag can be set to True when the relationship references an object via many-to-one using local foreign keys that are not nullable, or when the reference is one-to-one or a collection that is guaranteed to have one or at least one entry.

  If the joined-eager load is chained onto an existing LEFT OUTER JOIN, innerjoin=True will be bypassed and the join will continue to chain as LEFT OUTER JOIN so that the results don’t change. As an alternative, specify the value "nested". This will instead nest the join on the right side, e.g. using the form “a LEFT OUTER JOIN (b JOIN c)”.

  New in version 0.9.4: Added innerjoin="nested" option to support nesting of eager “inner” joins.

  See also

  what_kind_of_loading - Discussion of some details of various loader options.

  :paramref:`.joinedload.innerjoin` - loader option version

• join_depth –

  when non-None, an integer value indicating how many levels deep “eager” loaders should join on a self-referring or cyclical relationship. The number counts how many times the same Mapper shall be present in the loading condition along a particular join branch. When left at its default of None, eager loaders will stop chaining when they encounter a the same target mapper which is already higher up in the chain. This option applies both to joined- and subquery- eager loaders.

  See also

  self_referential_eager_loading - Introductory documentation and examples.

• lazy=’select’ –

  specifies how the related items should be loaded. Default value is select. Values include:

  • select - items should be loaded lazily when the property is first accessed, using a separate SELECT statement, or identity map fetch for simple many-to-one references.
  • immediate - items should be loaded as the parents are loaded, using a separate SELECT statement, or identity map fetch for simple many-to-one references.
  • joined - items should be loaded “eagerly” in the same query as that of the parent, using a JOIN or LEFT OUTER JOIN. Whether the join is “outer” or not is determined by the :paramref:`~.relationship.innerjoin` parameter.
  • subquery - items should be loaded “eagerly” as the parents are loaded, using one additional SQL statement, which issues a JOIN to a subquery of the original statement, for each collection requested.
  • noload - no loading should occur at any time. This is to support “write-only” attributes, or attributes which are populated in some manner specific to the application.
  • dynamic - the attribute will return a pre-configured Query object for all read operations, onto which further filtering operations can be applied before iterating the results. See the section dynamic_relationship for more details.
  • True - a synonym for ‘select’
  • False - a synonym for ‘joined’
  • None - a synonym for ‘noload’

  See also

  /orm/loading - Full documentation on relationship loader configuration.

  dynamic_relationship - detail on the dynamic option.

• load_on_pending=False –

  Indicates loading behavior for transient or pending parent objects.

  When set to True, causes the lazy-loader to issue a query for a parent object that is not persistent, meaning it has never been flushed. This may take effect for a pending object when autoflush is disabled, or for a transient object that has been “attached” to a Session but is not part of its pending collection.

  The :paramref:`~.relationship.load_on_pending` flag does not improve behavior when the ORM is used normally - object references should be constructed at the object level, not at the foreign key level, so that they are present in an ordinary way before a flush proceeds. This flag is not not intended for general use.

  See also

  Session.enable_relationship_loading() - this method establishes “load on pending” behavior for the whole object, and also allows loading on objects that remain transient or detached.

• order_by –

  indicates the ordering that should be applied when loading these items. :paramref:`~.relationship.order_by` is expected to refer to one of the Column objects to which the target class is mapped, or the attribute itself bound to the target class which refers to the column.

  :paramref:`~.relationship.order_by` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

• passive_deletes=False –

  Indicates loading behavior during delete operations.

  A value of True indicates that unloaded child items should not be loaded during a delete operation on the parent. Normally, when a parent item is deleted, all child items are loaded so that they can either be marked as deleted, or have their foreign key to the parent set to NULL. Marking this flag as True usually implies an ON DELETE <CASCADE|SET NULL> rule is in place which will handle updating/deleting child rows on the database side.

  Additionally, setting the flag to the string value ‘all’ will disable the “nulling out” of the child foreign keys, when there is no delete or delete-orphan cascade enabled. This is typically used when a triggering or error raise scenario is in place on the database side. Note that the foreign key attributes on in-session child objects will not be changed after a flush occurs so this is a very special use-case setting.

  See also

  passive_deletes - Introductory documentation and examples.

• passive_updates=True –

  Indicates loading and INSERT/UPDATE/DELETE behavior when the source of a foreign key value changes (i.e. an “on update” cascade), which are typically the primary key columns of the source row.

  When True, it is assumed that ON UPDATE CASCADE is configured on the foreign key in the database, and that the database will handle propagation of an UPDATE from a source column to dependent rows. Note that with databases which enforce referential integrity (i.e. PostgreSQL, MySQL with InnoDB tables), ON UPDATE CASCADE is required for this operation. The relationship() will update the value of the attribute on related items which are locally present in the session during a flush.

  When False, it is assumed that the database does not enforce referential integrity and will not be issuing its own CASCADE operation for an update. The relationship() will issue the appropriate UPDATE statements to the database in response to the change of a referenced key, and items locally present in the session during a flush will also be refreshed.

  This flag should probably be set to False if primary key changes are expected and the database in use doesn’t support CASCADE (i.e. SQLite, MySQL MyISAM tables).

  See also

  passive_updates - Introductory documentation and examples.

  :paramref:`.mapper.passive_updates` - a similar flag which takes effect for joined-table inheritance mappings.

• post_update –

  this indicates that the relationship should be handled by a second UPDATE statement after an INSERT or before a DELETE. Currently, it also will issue an UPDATE after the instance was UPDATEd as well, although this technically should be improved. This flag is used to handle saving bi-directional dependencies between two individual rows (i.e. each row references the other), where it would otherwise be impossible to INSERT or DELETE both rows fully since one row exists before the other. Use this flag when a particular mapping arrangement will incur two rows that are dependent on each other, such as a table that has a one-to-many relationship to a set of child rows, and also has a column that references a single child row within that list (i.e. both tables contain a foreign key to each other). If a flush operation returns an error that a “cyclical dependency” was detected, this is a cue that you might want to use :paramref:`~.relationship.post_update` to “break” the cycle.

  See also

  post_update - Introductory documentation and examples.

• primaryjoin –

  a SQL expression that will be used as the primary join of this child object against the parent object, or in a many-to-many relationship the join of the primary object to the association table. By default, this value is computed based on the foreign key relationships of the parent and child tables (or association table).

  :paramref:`~.relationship.primaryjoin` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

  See also

  relationship_primaryjoin

• remote_side –

  used for self-referential relationships, indicates the column or list of columns that form the “remote side” of the relationship.

  :paramref:`.relationship.remote_side` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

  Changed in version 0.8: The remote() annotation can also be applied directly to the primaryjoin expression, which is an alternate, more specific system of describing which columns in a particular primaryjoin should be considered “remote”.

  See also

  self_referential - in-depth explanation of how :paramref:`~.relationship.remote_side` is used to configure self-referential relationships.

  remote() - an annotation function that accomplishes the same purpose as :paramref:`~.relationship.remote_side`, typically when a custom :paramref:`~.relationship.primaryjoin` condition is used.

• query_class –

  a Query subclass that will be used as the base of the “appender query” returned by a “dynamic” relationship, that is, a relationship that specifies lazy="dynamic" or was otherwise constructed using the orm.dynamic_loader() function.

  See also

  dynamic_relationship - Introduction to “dynamic” relationship loaders.

• secondaryjoin –

  a SQL expression that will be used as the join of an association table to the child object. By default, this value is computed based on the foreign key relationships of the association and child tables.

  :paramref:`~.relationship.secondaryjoin` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

  See also

  relationship_primaryjoin

• single_parent –

  when True, installs a validator which will prevent objects from being associated with more than one parent at a time. This is used for many-to-one or many-to-many relationships that should be treated either as one-to-one or one-to-many. Its usage is optional, except for relationship() constructs which are many-to-one or many-to-many and also specify the delete-orphan cascade option. The relationship() construct itself will raise an error instructing when this option is required.

  See also

  unitofwork_cascades - includes detail on when the :paramref:`~.relationship.single_parent` flag may be appropriate.

• uselist –

  a boolean that indicates if this property should be loaded as a list or a scalar. In most cases, this value is determined automatically by relationship() at mapper configuration time, based on the type and direction of the relationship - one to many forms a list, many to one forms a scalar, many to many is a list. If a scalar is desired where normally a list would be present, such as a bi-directional one-to-one relationship, set :paramref:`~.relationship.uselist` to False.

  The :paramref:`~.relationship.uselist` flag is also available on an existing relationship() construct as a read-only attribute, which can be used to determine if this relationship() deals with collections or scalar attributes:

  >>> User.addresses.property.uselist
  True
  

  See also

  relationships_one_to_one - Introduction to the “one to one” relationship pattern, which is typically when the :paramref:`~.relationship.uselist` flag is needed.

• viewonly=False – when set to True, the relationship is used only for loading objects, and not for any persistence operation. A relationship() which specifies :paramref:`~.relationship.viewonly` can work with a wider range of SQL operations within the :paramref:`~.relationship.primaryjoin` condition, including operations that feature the use of a variety of comparison operators as well as SQL functions such as cast(). The :paramref:`~.relationship.viewonly` flag is also of general use when defining any kind of relationship() that doesn’t represent the full set of related objects, to prevent modifications of the collection from resulting in persistence operations.

Tests

Tests are lacking for the db api layer and for the sqlalchemy driver. Failures in the drivers would be detected in other test cases, though.