查询API¶
Query API
本文件描述了如何使用 QuerySet 构建查询。
请确保查看 examples 以便更好地理解。
你可以从模型类开始你的查询:
Event.filter(id=1)
模型本身有几个方法来开始查询:
filter(*args, **kwargs)
- 创建带有给定过滤条件的 QuerySetexclude(*args, **kwargs)
- 创建带有给定排除条件的 QuerySetall()
- 创建不带过滤条件的 QuerySetfirst()
- 创建限于一个对象的 QuerySet,并返回实例而不是列表annotate()
- 创建带有给定注释的 QuerySet
这些方法返回一个 QuerySet
对象,允许进一步的过滤和一些更复杂的操作。
模型类还具有以下方法来创建对象:
create(**kwargs)
- 使用给定的 kwargs 创建对象get_or_create(defaults, **kwargs)
- 获取给定 kwargs 的对象,如果未找到,则使用来自 defaults 字典的附加 kwargs 创建它
模型实例本身还具有这些方法:
save()
- 更新实例,或在从未保存之前插入它delete()
- 从数据库中删除实例fetch_related(*args)
- 获取与实例相关的对象。它可以获取外键关系、反向外键关系和多对多关系。它还可以获取可变深度的相关对象,例如:await team.fetch_related('events__tournament')
- 这将获取团队的所有事件,并且每个事件的锦标赛也将被预取。在获取对象后,它们应该可以正常使用,例如:team.events[0].tournament.name
与实例上相关对象的另一种处理方法是在 async for
中显式查询它们:
async for team in event.participants:
print(team.name)
你也可以这样过滤相关对象:
await team.events.filter(name='First')
这将返回一个带有预定义过滤条件的 QuerySet 对象。
This document describes how to use QuerySet to build your queries
Be sure to check examples for better understanding
You start your query from your model class:
Event.filter(id=1)
There are several method on model itself to start query:
filter(*args, **kwargs)
- create QuerySet with given filtersexclude(*args, **kwargs)
- create QuerySet with given excluding filtersall()
- create QuerySet without filtersfirst()
- create QuerySet limited to one object and returning instance instead of listannotate()
- create QuerySet with given annotation
This method returns QuerySet
object, that allows further filtering and some more complex operations
Also model class have this methods to create object:
create(**kwargs)
- creates object with given kwargsget_or_create(defaults, **kwargs)
- gets object for given kwargs, if not found create it with additional kwargs from defaults dict
Also instance of model itself has these methods:
save()
- update instance, or insert it, if it was never saved beforedelete()
- delete instance from dbfetch_related(*args)
- fetches objects related to instance. It can fetch FK relation, Backward-FK relations and M2M relations. It also can fetch variable depth of related objects like this:await team.fetch_related('events__tournament')
- this will fetch all events for team, and for each of this events their tournament will be prefetched too. After fetching objects they should be available normally like this:team.events[0].tournament.name
Another approach to work with related objects on instance is to query them explicitly in async for
:
async for team in event.participants:
print(team.name)
You also can filter related objects like this:
await team.events.filter(name='First')
which will return you a QuerySet object with predefined filter
QuerySet¶
在你从对象获得查询集后,可以对其执行以下操作:
- class tortoise.queryset.QuerySetSingle(*args, **kwargs)[source]¶
Awaiting on this will resolve a single instance of the Model object, and not a sequence.
- class tortoise.queryset.QuerySet(model)[source]¶
- classmethod __class_getitem__(params)¶
Parameterizes a generic class.
At least, parameterizing a generic class is the main thing this method does. For example, for some generic class Foo, this is called when we do Foo[int] - there, with cls=Foo and params=int.
However, note that this method is also called when defining generic classes in the first place with class Foo(Generic[T]): ….
- __getitem__(key)[source]¶
Query offset and limit for Queryset.
- Raises:¶
ParamsError – QuerySet indices must be slices.
ParamsError – Slice steps should be 1 or None.
ParamsError – Slice start should be non-negative number or None.
ParamsError – Slice stop should be non-negative number greater that slice start,
or None.
-
bulk_create(objects, batch_size=
None
, ignore_conflicts=False
, update_fields=None
, on_conflict=None
)[source]¶ This method inserts the provided list of objects into the database in an efficient manner (generally only 1 query, no matter how many objects there are).
- Parameters:¶
- Raises:¶
ValueError – If params do not meet specifications
- Return type:¶
BulkCreateQuery
[Model]
-
bulk_update(objects, fields, batch_size=
None
)[source]¶ Update the given fields in each of the given objects in the database.
- distinct()[source]¶
Make QuerySet distinct.
Only makes sense in combination with a
.values()
or.values_list()
as it precedes all the fetched fields with a distinct.
- async explain()[source]¶
Fetch and return information about the query execution plan.
This is done by executing an
EXPLAIN
query whose exact prefix depends on the database backend, as documented below.PostgreSQL:
EXPLAIN (FORMAT JSON, VERBOSE) ...
SQLite:
EXPLAIN QUERY PLAN ...
MySQL:
EXPLAIN FORMAT=JSON ...
Note
This is only meant to be used in an interactive environment for debugging and query optimization. The output format may (and will) vary greatly depending on the database backend.
- Return type:¶
Any
- filter(*args, **kwargs)[source]¶
Filters QuerySet by given kwargs. You can filter by related objects like this:
Team.filter(events__tournament__name='Test')
You can also pass Q objects to filters as args.
- first()[source]¶
Limit queryset to one object and return one object instead of list.
- Return type:¶
QuerySetSingle
[Optional
[Model]]
- force_index(*index_names)[source]¶
The FORCE INDEX hint acts like USE INDEX (index_list), with the addition that a table scan is assumed to be very expensive.
- get(*args, **kwargs)[source]¶
Fetch exactly one object matching the parameters.
- Return type:¶
QuerySetSingle
[Model]
- get_or_none(*args, **kwargs)[source]¶
Fetch exactly one object matching the parameters.
- Return type:¶
QuerySetSingle
[Optional
[Model]]
- group_by(*fields)[source]¶
Make QuerySet returns list of dict or tuple with group by.
Must call before .values() or .values_list()
- async in_bulk(id_list, field_name)[source]¶
Return a dictionary mapping each of the given IDs to the object with that ID. If id_list isn’t provided, evaluate the entire QuerySet.
- limit(limit)[source]¶
Limits QuerySet to given length.
- Raises:¶
ParamsError – Limit should be non-negative number.
- Return type:¶
QuerySet
[Model]
- offset(offset)[source]¶
Query offset for QuerySet.
- Raises:¶
ParamsError – Offset should be non-negative number.
- Return type:¶
QuerySet
[Model]
- only(*fields_for_select)[source]¶
Fetch ONLY the specified fields to create a partial model.
Persisting changes on the model is allowed only when:
All the fields you want to update is specified in
<model>.save(update_fields=[...])
You included the Model primary key in the .only(…)`
To protect against common mistakes we ensure that errors get raised:
If you access a field that is not specified, you will get an
AttributeError
.If you do a
<model>.save()
aIncompleteInstanceError
will be raised as the model is, as requested, incomplete.If you do a
<model>.save(update_fields=[...])
and you didn’t include the primary key in the.only(...)
, thenIncompleteInstanceError
will be raised indicating that updates can’t be done without the primary key being known.If you do a
<model>.save(update_fields=[...])
and one of the fields inupdate_fields
was not in the.only(...)
, thenIncompleteInstanceError
as that field is not available to be updated.
- order_by(*orderings)[source]¶
Accept args to filter by in format like this:
.order_by('name', '-tournament__name')
Supports ordering by related models too. A ‘-’ before the name will result in descending sort order, default is ascending.
- Raises:¶
FieldError – If unknown field has been provided.
- Return type:¶
QuerySet
[Model]
Like
.fetch_related()
on instance, but works on all objects in QuerySet.FieldError – If the field to prefetch on is not a relation, or not found.
QuerySet
[Model]
- resolve_filters(model, q_objects, annotations, custom_filters)¶
Builds the common filters for a QuerySet.
- resolve_ordering(model, table, orderings, annotations)¶
Applies standard ordering to QuerySet.
- Parameters:¶
- Raises:¶
FieldError – If a field provided does not exist in model.
- Return type:¶
None
-
select_for_update(nowait=
False
, skip_locked=False
, of=()
)[source]¶ Make QuerySet select for update.
Returns a queryset that will lock rows until the end of the transaction, generating a SELECT … FOR UPDATE SQL statement on supported databases.
Return a new QuerySet instance that will select related objects.
If fields are specified, they must be ForeignKey fields and only those related objects are included in the selection.
QuerySet
[Model]
- update(**kwargs)[source]¶
Update all objects in QuerySet with given kwargs.
Will instead of returning a resultset, update the data in the DB itself.
- Return type:¶
- use_index(*index_names)[source]¶
The USE INDEX (index_list) hint tells MySQL to use only one of the named indexes to find rows in the table.
- values(*args, **kwargs)[source]¶
Make QuerySet return dicts instead of objects.
If call after .get(), .get_or_none() or .first() return dict instead of object.
Can pass names of fields to fetch, or as a
field_name='name_in_dict'
kwarg.If no arguments are passed it will default to a dict containing all fields.
- Raises:¶
FieldError – If duplicate key has been provided.
- Return type:¶
ValuesQuery
[Literal
[False]]
-
values_list(*fields_, flat=
False
)[source]¶ Make QuerySet returns list of tuples for given args instead of objects.
If call after .get(), .get_or_none() or .first() return tuples for given args instead of object.
If
`flat=True
and only one arg is passed can return flat list or just scalar.If no arguments are passed it will default to a tuple containing all fields in order of declaration.
- Return type:¶
ValuesListQuery
[Literal
[False]]
-
class tortoise.queryset.BulkCreateQuery(model, db, objects, batch_size=
None
, ignore_conflicts=False
, update_fields=None
, on_conflict=None
)[source]¶
-
class tortoise.queryset.BulkUpdateQuery(model, db, q_objects, annotations, custom_filters, limit, orderings, objects, fields, batch_size=
None
)[source]¶
- class tortoise.queryset.CountQuery(model, db, q_objects, annotations, custom_filters, limit, offset, force_indexes, use_indexes)[source]¶
- class tortoise.queryset.DeleteQuery(model, db, q_objects, annotations, custom_filters, limit, orderings)[source]¶
- class tortoise.queryset.ExistsQuery(model, db, q_objects, annotations, custom_filters, force_indexes, use_indexes)[source]¶
- class tortoise.queryset.FieldSelectQuery(model, annotations)[source]¶
- class tortoise.queryset.UpdateQuery(model, update_kwargs, db, q_objects, annotations, custom_filters, limit, orderings)[source]¶
- class tortoise.queryset.ValuesListQuery(model, db, q_objects, single, raise_does_not_exist, fields_for_select_list, limit, offset, distinct, orderings, flat, annotations, custom_filters, group_bys, force_indexes, use_indexes)[source]¶
- class tortoise.queryset.ValuesQuery(model, db, q_objects, single, raise_does_not_exist, fields_for_select, limit, offset, distinct, orderings, annotations, custom_filters, group_bys, force_indexes, use_indexes)[source]¶
QuerySet 可以构建、过滤并在不实际访问数据库的情况下传递。只有在你 await
查询集后,它才会生成查询并在数据库中运行。
以下是一些使用查询集的常见场景(我们使用在 开始入门 中定义的模型):
常规选择模型实例:
await Event.filter(name__startswith='FIFA')
该查询将获取所有 name
以 FIFA
开头的事件,其中 name
是模型中定义的字段,startswith
是过滤修饰符。请注意,修饰符应通过双下划线分隔。你可以在本文档的 Filtering
部分阅读有关过滤修饰符的更多信息。
你也可以使用 .exclude()
来过滤查询:
await Team.exclude(name__icontains='junior')
作为更有趣的案例,当你处理相关数据时,你还可以围绕相关实体构建查询:
# 获取所有锦标赛名称为 "World Cup" 的事件
await Event.filter(tournament__name='World Cup')
# 获取参与事件 ID 为 1、2、3 的所有团队
await Team.filter(events__id__in=[1, 2, 3])
# 获取参与锦标赛的名称中包含 "junior" 的团队的所有锦标赛
await Tournament.filter(event__participants__name__icontains='junior').distinct()
通常,你不仅想按相关数据进行过滤,还希望获取该相关数据。你可以使用 .prefetch_related()
来做到这一点:
# 这将获取事件,并且每个事件的 ``.tournament`` 字段将填充相应的 ``Tournament`` 实例
await Event.all().prefetch_related('tournament')
# 这将获取锦标赛及其事件和每个事件的团队
tournament_list = await Tournament.all().prefetch_related('events__participants')
# 获取的多对多和反向外键关系的结果存储在类似列表的容器中
for tournament in tournament_list:
print([e.name for e in tournament.events])
关于 prefetch_related()
的一般规则是,每个相关模型的深度层级产生一个额外的查询,因此 .prefetch_related('events__participants')
将产生两个额外的查询来获取你的数据。
有时,当性能至关重要时,你不希望进行额外的查询。在这种情况下,你可以使用 values()
或 values_list()
来生成更高效的查询。
# 这将返回包含键 'id'、'name' 和 'tournament_name' 的字典列表,
# 'tournament_name' 将由相关锦标赛的名称填充。
# 并且将通过一个查询完成
events = await Event.filter(id__in=[1, 2, 3]).values('id', 'name', tournament_name='tournament__name')
查询集还通过 .annotate()
方法支持聚合和数据库函数。
from tortoise.functions import Count, Trim, Lower, Upper, Coalesce
# 该查询将获取所有事件数量为 10 或更多的锦标赛,并将
# 在实例中填充字段 `.events_count`,其值相应
await Tournament.annotate(events_count=Count('events')).filter(events_count__gte=10)
await Tournament.annotate(clean_name=Trim('name')).filter(clean_name='tournament')
await Tournament.annotate(name_upper=Upper('name')).filter(name_upper='TOURNAMENT')
await Tournament.annotate(name_lower=Lower('name')).filter(name_lower='tournament')
await Tournament.annotate(desc_clean=Coalesce('desc', '')).filter(desc_clean='')
请查看 examples 以了解其工作原理。
After you obtained queryset from object you can do following operations with it:
- class tortoise.queryset.QuerySetSingle(*args, **kwargs)[source]¶
Awaiting on this will resolve a single instance of the Model object, and not a sequence.
- class tortoise.queryset.QuerySet(model)[source]¶
- classmethod __class_getitem__(params)¶
Parameterizes a generic class.
At least, parameterizing a generic class is the main thing this method does. For example, for some generic class Foo, this is called when we do Foo[int] - there, with cls=Foo and params=int.
However, note that this method is also called when defining generic classes in the first place with class Foo(Generic[T]): ….
- __getitem__(key)[source]¶
Query offset and limit for Queryset.
- Raises:¶
ParamsError – QuerySet indices must be slices.
ParamsError – Slice steps should be 1 or None.
ParamsError – Slice start should be non-negative number or None.
ParamsError – Slice stop should be non-negative number greater that slice start,
or None.
-
bulk_create(objects, batch_size=
None
, ignore_conflicts=False
, update_fields=None
, on_conflict=None
)[source]¶ This method inserts the provided list of objects into the database in an efficient manner (generally only 1 query, no matter how many objects there are).
- Parameters:¶
- Raises:¶
ValueError – If params do not meet specifications
- Return type:¶
BulkCreateQuery
[Model]
-
bulk_update(objects, fields, batch_size=
None
)[source]¶ Update the given fields in each of the given objects in the database.
- distinct()[source]¶
Make QuerySet distinct.
Only makes sense in combination with a
.values()
or.values_list()
as it precedes all the fetched fields with a distinct.
- async explain()[source]¶
Fetch and return information about the query execution plan.
This is done by executing an
EXPLAIN
query whose exact prefix depends on the database backend, as documented below.PostgreSQL:
EXPLAIN (FORMAT JSON, VERBOSE) ...
SQLite:
EXPLAIN QUERY PLAN ...
MySQL:
EXPLAIN FORMAT=JSON ...
Note
This is only meant to be used in an interactive environment for debugging and query optimization. The output format may (and will) vary greatly depending on the database backend.
- Return type:¶
Any
- filter(*args, **kwargs)[source]¶
Filters QuerySet by given kwargs. You can filter by related objects like this:
Team.filter(events__tournament__name='Test')
You can also pass Q objects to filters as args.
- first()[source]¶
Limit queryset to one object and return one object instead of list.
- Return type:¶
QuerySetSingle
[Optional
[Model]]
- force_index(*index_names)[source]¶
The FORCE INDEX hint acts like USE INDEX (index_list), with the addition that a table scan is assumed to be very expensive.
- get(*args, **kwargs)[source]¶
Fetch exactly one object matching the parameters.
- Return type:¶
QuerySetSingle
[Model]
- get_or_none(*args, **kwargs)[source]¶
Fetch exactly one object matching the parameters.
- Return type:¶
QuerySetSingle
[Optional
[Model]]
- group_by(*fields)[source]¶
Make QuerySet returns list of dict or tuple with group by.
Must call before .values() or .values_list()
- async in_bulk(id_list, field_name)[source]¶
Return a dictionary mapping each of the given IDs to the object with that ID. If id_list isn’t provided, evaluate the entire QuerySet.
- limit(limit)[source]¶
Limits QuerySet to given length.
- Raises:¶
ParamsError – Limit should be non-negative number.
- Return type:¶
QuerySet
[Model]
- offset(offset)[source]¶
Query offset for QuerySet.
- Raises:¶
ParamsError – Offset should be non-negative number.
- Return type:¶
QuerySet
[Model]
- only(*fields_for_select)[source]¶
Fetch ONLY the specified fields to create a partial model.
Persisting changes on the model is allowed only when:
All the fields you want to update is specified in
<model>.save(update_fields=[...])
You included the Model primary key in the .only(…)`
To protect against common mistakes we ensure that errors get raised:
If you access a field that is not specified, you will get an
AttributeError
.If you do a
<model>.save()
aIncompleteInstanceError
will be raised as the model is, as requested, incomplete.If you do a
<model>.save(update_fields=[...])
and you didn’t include the primary key in the.only(...)
, thenIncompleteInstanceError
will be raised indicating that updates can’t be done without the primary key being known.If you do a
<model>.save(update_fields=[...])
and one of the fields inupdate_fields
was not in the.only(...)
, thenIncompleteInstanceError
as that field is not available to be updated.
- order_by(*orderings)[source]¶
Accept args to filter by in format like this:
.order_by('name', '-tournament__name')
Supports ordering by related models too. A ‘-’ before the name will result in descending sort order, default is ascending.
- Raises:¶
FieldError – If unknown field has been provided.
- Return type:¶
QuerySet
[Model]
- prefetch_related(*args)[source]¶
Like
.fetch_related()
on instance, but works on all objects in QuerySet.- Raises:¶
FieldError – If the field to prefetch on is not a relation, or not found.
- Return type:¶
QuerySet
[Model]
- resolve_filters(model, q_objects, annotations, custom_filters)¶
Builds the common filters for a QuerySet.
- resolve_ordering(model, table, orderings, annotations)¶
Applies standard ordering to QuerySet.
- Parameters:¶
- Raises:¶
FieldError – If a field provided does not exist in model.
- Return type:¶
None
-
select_for_update(nowait=
False
, skip_locked=False
, of=()
)[source]¶ Make QuerySet select for update.
Returns a queryset that will lock rows until the end of the transaction, generating a SELECT … FOR UPDATE SQL statement on supported databases.
- select_related(*fields)[source]¶
Return a new QuerySet instance that will select related objects.
If fields are specified, they must be ForeignKey fields and only those related objects are included in the selection.
- update(**kwargs)[source]¶
Update all objects in QuerySet with given kwargs.
Will instead of returning a resultset, update the data in the DB itself.
- Return type:¶
- use_index(*index_names)[source]¶
The USE INDEX (index_list) hint tells MySQL to use only one of the named indexes to find rows in the table.
- values(*args, **kwargs)[source]¶
Make QuerySet return dicts instead of objects.
If call after .get(), .get_or_none() or .first() return dict instead of object.
Can pass names of fields to fetch, or as a
field_name='name_in_dict'
kwarg.If no arguments are passed it will default to a dict containing all fields.
- Raises:¶
FieldError – If duplicate key has been provided.
- Return type:¶
ValuesQuery
[Literal
[False]]
-
values_list(*fields_, flat=
False
)[source]¶ Make QuerySet returns list of tuples for given args instead of objects.
If call after .get(), .get_or_none() or .first() return tuples for given args instead of object.
If
`flat=True
and only one arg is passed can return flat list or just scalar.If no arguments are passed it will default to a tuple containing all fields in order of declaration.
- Return type:¶
ValuesListQuery
[Literal
[False]]
-
class tortoise.queryset.BulkCreateQuery(model, db, objects, batch_size=
None
, ignore_conflicts=False
, update_fields=None
, on_conflict=None
)[source]¶
-
class tortoise.queryset.BulkUpdateQuery(model, db, q_objects, annotations, custom_filters, limit, orderings, objects, fields, batch_size=
None
)[source]¶
- class tortoise.queryset.CountQuery(model, db, q_objects, annotations, custom_filters, limit, offset, force_indexes, use_indexes)[source]¶
- class tortoise.queryset.DeleteQuery(model, db, q_objects, annotations, custom_filters, limit, orderings)[source]¶
- class tortoise.queryset.ExistsQuery(model, db, q_objects, annotations, custom_filters, force_indexes, use_indexes)[source]¶
- class tortoise.queryset.FieldSelectQuery(model, annotations)[source]¶
- class tortoise.queryset.UpdateQuery(model, update_kwargs, db, q_objects, annotations, custom_filters, limit, orderings)[source]¶
- class tortoise.queryset.ValuesListQuery(model, db, q_objects, single, raise_does_not_exist, fields_for_select_list, limit, offset, distinct, orderings, flat, annotations, custom_filters, group_bys, force_indexes, use_indexes)[source]¶
- class tortoise.queryset.ValuesQuery(model, db, q_objects, single, raise_does_not_exist, fields_for_select, limit, offset, distinct, orderings, annotations, custom_filters, group_bys, force_indexes, use_indexes)[source]¶
QuerySet could be constructed, filtered and passed around without actually hitting database.
Only after you await
QuerySet, it will generate query and run it against database.
Here are some common usage scenarios with QuerySet (we are using models defined in 开始入门):
Regular select into model instances:
await Event.filter(name__startswith='FIFA')
This query will get you all events with name
starting with FIFA
, where name
is fields
defined on model, and startswith
is filter modifier. Take note, that modifiers should
be separated by double underscore. You can read more on filter modifiers in Filtering
section of this document.
It’s also possible to filter your queries with .exclude()
:
await Team.exclude(name__icontains='junior')
As more interesting case, when you are working with related data, you could also build your query around related entities:
# getting all events, which tournament name is "World Cup"
await Event.filter(tournament__name='World Cup')
# Gets all teams participating in events with ids 1, 2, 3
await Team.filter(events__id__in=[1,2,3])
# Gets all tournaments where teams with "junior" in their name are participating
await Tournament.filter(event__participants__name__icontains='junior').distinct()
Usually you not only want to filter by related data, but also get that related data as well.
You could do it using .prefetch_related()
:
# This will fetch events, and for each of events ``.tournament`` field will be populated with
# corresponding ``Tournament`` instance
await Event.all().prefetch_related('tournament')
# This will fetch tournament with their events and teams for each event
tournament_list = await Tournament.all().prefetch_related('events__participants')
# Fetched result for m2m and backward fk relations are stored in list-like container
for tournament in tournament_list:
print([e.name for e in tournament.events])
General rule about how prefetch_related()
works is that each level of depth of related models
produces 1 additional query, so .prefetch_related('events__participants')
will produce two
additional queries to fetch your data.
Sometimes, when performance is crucial, you don’t want to make additional queries like this.
In cases like this you could use values()
or values_list()
to produce more efficient query
# This will return list of dicts with keys 'id', 'name', 'tournament_name' and
# 'tournament_name' will be populated by name of related tournament.
# And it will be done in one query
events = await Event.filter(id__in=[1,2,3]).values('id', 'name', tournament_name='tournament__name')
QuerySet also supports aggregation and database functions through .annotate()
method
from tortoise.functions import Count, Trim, Lower, Upper, Coalesce
# This query will fetch all tournaments with 10 or more events, and will
# populate filed `.events_count` on instances with corresponding value
await Tournament.annotate(events_count=Count('events')).filter(events_count__gte=10)
await Tournament.annotate(clean_name=Trim('name')).filter(clean_name='tournament')
await Tournament.annotate(name_upper=Upper('name')).filter(name_upper='TOURNAMENT')
await Tournament.annotate(name_lower=Lower('name')).filter(name_lower='tournament')
await Tournament.annotate(desc_clean=Coalesce('desc', '')).filter(desc_clean='')
Check examples to see it all in work
外键¶
Foreign Key
Tortoise ORM 提供了用于处理 FK 关系的 API
Tortoise ORM provides an API for working with FK relations
- class tortoise.fields.relational.ReverseRelation(remote_model, relation_field, instance, from_field)[source]¶
Relation container for
ForeignKeyField()
.
- tortoise.fields.relational.ForeignKeyNullableRelation¶
Type hint for the result of accessing the
ForeignKeyField()
field in the model when obtained model can be nullable.alias of
ForeignKeyFieldInstance
[MODEL
] |None
- tortoise.fields.relational.ForeignKeyRelation¶
Type hint for the result of accessing the
ForeignKeyField()
field in the model.alias of
ForeignKeyFieldInstance
[MODEL
]
一对一¶
One to One
- tortoise.fields.relational.OneToOneNullableRelation¶
Type hint for the result of accessing the
OneToOneField()
field in the model when obtained model can be nullable.alias of
OneToOneFieldInstance
[MODEL
] |None
- tortoise.fields.relational.OneToOneRelation¶
Type hint for the result of accessing the
OneToOneField()
field in the model.alias of
OneToOneFieldInstance
[MODEL
]
多对多¶
Many to Many
Tortoise ORM 提供了一个用于处理多对多(M2M)关系的 API。
- class tortoise.fields.relational.ManyToManyRelation(instance, m2m_field)[source]¶
Many-to-many relation container for
ManyToManyField()
.- classmethod __class_getitem__(params)¶
Parameterizes a generic class.
At least, parameterizing a generic class is the main thing this method does. For example, for some generic class Foo, this is called when we do Foo[int] - there, with cls=Foo and params=int.
However, note that this method is also called when defining generic classes in the first place with class Foo(Generic[T]): ….
-
async add(*instances, using_db=
None
)[source]¶ Adds one or more of
instances
to the relation.If it is already added, it will be silently ignored.
- Raises:¶
OperationalError – If Object to add is not saved.
- Return type:¶
None
你可以这样使用它们:
await event.participants.add(participant_1, participant_2)
Tortoise ORM provides an API for working with M2M relations
- class tortoise.fields.relational.ManyToManyRelation(instance, m2m_field)[source]¶
Many-to-many relation container for
ManyToManyField()
.- classmethod __class_getitem__(params)¶
Parameterizes a generic class.
At least, parameterizing a generic class is the main thing this method does. For example, for some generic class Foo, this is called when we do Foo[int] - there, with cls=Foo and params=int.
However, note that this method is also called when defining generic classes in the first place with class Foo(Generic[T]): ….
-
async add(*instances, using_db=
None
)[source]¶ Adds one or more of
instances
to the relation.If it is already added, it will be silently ignored.
- Raises:¶
OperationalError – If Object to add is not saved.
- Return type:¶
None
You can use them like this:
await event.participants.add(participant_1, participant_2)
过滤¶
Filtering
使用 .filter()
方法时,可以使用多个修饰符来指定所需的操作。
teams = await Team.filter(name__icontains='CON')
not
in
- 检查字段的值是否在传入的列表中not_in
gte
- 大于或等于传入的值gt
- 大于传入的值lte
- 小于或等于传入的值lt
- 小于传入的值range
- 在两个给定值之间isnull
- 字段为 nullnot_isnull
- 字段不为 nullcontains
- 字段包含指定子字符串icontains
- 不区分大小写的contains
startswith
- 字段是否以值开头istartswith
- 不区分大小写的startswith
endswith
- 字段是否以值结尾iendswith
- 不区分大小写的endswith
iexact
- 不区分大小写的相等search
- 全文搜索
特别地,你可以使用以下之一过滤日期部分,注意目前只支持 PostgreSQL 和 MySQL,但不支持 SQLite:
class DatePart(Enum):
year = "YEAR"
quarter = "QUARTER"
month = "MONTH"
week = "WEEK"
day = "DAY"
hour = "HOUR"
minute = "MINUTE"
second = "SECOND"
microsecond = "MICROSECOND"
teams = await Team.filter(created_at__year=2020)
teams = await Team.filter(created_at__month=12)
teams = await Team.filter(created_at__day=5)
在 PostgreSQL 和 MySQL 中,你可以在 JSONField
中使用 contains
、contained_by
和 filter
选项:
class JSONModel:
data = fields.JSONField()
await JSONModel.create(data=["text", 3, {"msg": "msg2"}])
obj = await JSONModel.filter(data__contains=[{"msg": "msg2"}]).first()
await JSONModel.create(data=["text"])
await JSONModel.create(data=["tortoise", "msg"])
await JSONModel.create(data=["tortoise"])
objects = await JSONModel.filter(data__contained_by=["text", "tortoise", "msg"])
class JSONModel:
data = fields.JSONField()
await JSONModel.create(data={"breed": "labrador",
"owner": {
"name": "Boby",
"last": None,
"other_pets": [
{
"name": "Fishy",
}
],
},
})
obj1 = await JSONModel.filter(data__filter={"breed": "labrador"}).first()
obj2 = await JSONModel.filter(data__filter={"owner__name": "Boby"}).first()
obj3 = await JSONModel.filter(data__filter={"owner__other_pets__0__name": "Fishy"}).first()
obj4 = await JSONModel.filter(data__filter={"breed__not": "a"}).first()
obj5 = await JSONModel.filter(data__filter={"owner__name__isnull": True}).first()
obj6 = await JSONModel.filter(data__filter={"owner__last__not_isnull": False}).first()
在 PostgreSQL 和 MySQL 中,你可以使用 postgres_posix_regex
使用 POSIX 正则表达式进行比较:
在 PostgreSQL 中,这使用 ~
操作符,在 MySQL 中它使用 REGEXP
操作符。
class DemoModel:
demo_text = fields.TextField()
await DemoModel.create(demo_text="Hello World")
obj = await DemoModel.filter(demo_text__posix_regex="^Hello World$").first()
When using .filter()
method you can use number of modifiers to field names to specify desired operation
teams = await Team.filter(name__icontains='CON')
not
in
- checks if value of field is in passed listnot_in
gte
- greater or equals than passed valuegt
- greater than passed valuelte
- lower or equals than passed valuelt
- lower than passed valuerange
- between and given two valuesisnull
- field is nullnot_isnull
- field is not nullcontains
- field contains specified substringicontains
- case insensitivecontains
startswith
- if field starts with valueistartswith
- case insensitivestartswith
endswith
- if field ends with valueiendswith
- case insensitiveendswith
iexact
- case insensitive equalssearch
- full text search
Specially, you can filter date part with one of following, note that current only support PostgreSQL and MySQL, but not sqlite:
class DatePart(Enum):
year = "YEAR"
quarter = "QUARTER"
month = "MONTH"
week = "WEEK"
day = "DAY"
hour = "HOUR"
minute = "MINUTE"
second = "SECOND"
microsecond = "MICROSECOND"
teams = await Team.filter(created_at__year=2020)
teams = await Team.filter(created_at__month=12)
teams = await Team.filter(created_at__day=5)
In PostgreSQL and MYSQL, you can use the contains
, contained_by
and filter
options in JSONField
:
class JSONModel:
data = fields.JSONField()
await JSONModel.create(data=["text", 3, {"msg": "msg2"}])
obj = await JSONModel.filter(data__contains=[{"msg": "msg2"}]).first()
await JSONModel.create(data=["text"])
await JSONModel.create(data=["tortoise", "msg"])
await JSONModel.create(data=["tortoise"])
objects = await JSONModel.filter(data__contained_by=["text", "tortoise", "msg"])
class JSONModel:
data = fields.JSONField()
await JSONModel.create(data={"breed": "labrador",
"owner": {
"name": "Boby",
"last": None,
"other_pets": [
{
"name": "Fishy",
}
],
},
})
obj1 = await JSONModel.filter(data__filter={"breed": "labrador"}).first()
obj2 = await JSONModel.filter(data__filter={"owner__name": "Boby"}).first()
obj3 = await JSONModel.filter(data__filter={"owner__other_pets__0__name": "Fishy"}).first()
obj4 = await JSONModel.filter(data__filter={"breed__not": "a"}).first()
obj5 = await JSONModel.filter(data__filter={"owner__name__isnull": True}).first()
obj6 = await JSONModel.filter(data__filter={"owner__last__not_isnull": False}).first()
In PostgreSQL and MySQL, you can use postgres_posix_regex
to make comparisons using POSIX regular expressions:
On PostgreSQL, this uses the ~
operator, on MySQL it uses the REGEXP
operator.
class DemoModel:
demo_text = fields.TextField()
await DemoModel.create(demo_text="Hello World")
obj = await DemoModel.filter(demo_text__posix_regex="^Hello World$").first()
复杂的预获取¶
Complex prefetch
有时需要仅提取某些相关记录。你可以使用 Prefetch
对象来实现:
tournament_with_filtered = await Tournament.all().prefetch_related(
Prefetch('events', queryset=Event.filter(name='First'))
).first()
你可以在这里查看完整示例: 预取(Prefetching)
Sometimes it is required to fetch only certain related records. You can achieve it with Prefetch
object:
tournament_with_filtered = await Tournament.all().prefetch_related(
Prefetch('events', queryset=Event.filter(name='First'))
).first()
You can view full example here: 预取(Prefetching)