Skip to content

Commit

Permalink
bump version, update docs
Browse files Browse the repository at this point in the history
  • Loading branch information
collerek committed Dec 1, 2020
1 parent 4c4e624 commit 3ac767e
Show file tree
Hide file tree
Showing 13 changed files with 347 additions and 64 deletions.
2 changes: 1 addition & 1 deletion README.md
Original file line number Diff line number Diff line change
Expand Up @@ -154,7 +154,7 @@ assert len(tracks) == 1
* `bulk_create(objects: List[Model]) -> None`
* `bulk_update(objects: List[Model], columns: List[str] = None) -> None`
* `delete(each: bool = False, **kwargs) -> int`
* `all(self, **kwargs) -> List[Optional[Model]]`
* `all(**kwargs) -> List[Optional[Model]]`
* `filter(**kwargs) -> QuerySet`
* `exclude(**kwargs) -> QuerySet`
* `select_related(related: Union[List, str]) -> QuerySet`
Expand Down
2 changes: 1 addition & 1 deletion docs/index.md
Original file line number Diff line number Diff line change
Expand Up @@ -154,7 +154,7 @@ assert len(tracks) == 1
* `bulk_create(objects: List[Model]) -> None`
* `bulk_update(objects: List[Model], columns: List[str] = None) -> None`
* `delete(each: bool = False, **kwargs) -> int`
* `all(self, **kwargs) -> List[Optional[Model]]`
* `all(**kwargs) -> List[Optional[Model]]`
* `filter(**kwargs) -> QuerySet`
* `exclude(**kwargs) -> QuerySet`
* `select_related(related: Union[List, str]) -> QuerySet`
Expand Down
2 changes: 1 addition & 1 deletion docs/queries.md
Original file line number Diff line number Diff line change
Expand Up @@ -176,7 +176,7 @@ Return number of rows deleted.

### all

`all(self, **kwargs) -> List[Optional["Model"]]`
`all(**kwargs) -> List[Optional["Model"]]`

Returns all rows from a database for given model for set filter options.

Expand Down
313 changes: 273 additions & 40 deletions docs/relations.md
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,83 @@ By default it's child (source) `Model` name + s, like courses in snippet below:
--8<-- "../docs_src/fields/docs001.py"
```

Reverse relation exposes API to manage related objects also from parent side.

##### add

Adding child model from parent side causes adding related model to currently loaded parent relation,
as well as sets child's model foreign key value and updates the model.

```python
department = await Department(name="Science").save()
course = Course(name="Math", completed=False) # note - not saved

await department.courses.add(course)
assert course.pk is not None # child model was saved
# relation on child model is set and FK column saved in db
assert courses.department == department
# relation on parent model is also set
assert department.courses[0] == course
```

!!!warning
If you want to add child model on related model the primary key value for parent model **has to exist in database**.

Otherwise ormar will raise RelationshipInstanceError as it cannot set child's ForeignKey column value
if parent model has no primary key value.

That means that in example above the department has to be saved before you can call `department.courses.add()`.

##### remove

Removal of the related model one by one.

In reverse relation calling `remove()` does not remove the child model, but instead nulls it ForeignKey value.

```python
# continuing from above
await department.courses.remove(course)
assert len(department.courses) == 0
# course still exists and was saved in remove
assert course.pk is not None
assert course.department is None

# to remove child from db
await course.delete()
```

But if you want to clear the relation and delete the child at the same time you can issue:

```python
# this will not only clear the relation
# but also delete related course from db
await department.courses.remove(course, keep_reversed=False)
```

##### clear

Removal of all related models in one call.

Like remove by default `clear()` nulls the ForeigKey column on child model (all, not matter if they are loaded or not).

```python
# nulls department column on all courses related to this department
await department.courses.clear()
```

If you want to remove the children altogether from the database, set `keep_reversed=False`

```python
# deletes from db all courses related to this department
await department.courses.clear(keep_reversed=False)
```

##### QuerysetProxy

Reverse relation exposes QuerysetProxy API that allows you to query related model like you would issue a normal Query.

To read which methods of QuerySet are available read below [querysetproxy][querysetproxy]

#### related_name

But you can overwrite this name by providing `related_name` parameter like below:
Expand Down Expand Up @@ -94,7 +171,7 @@ Sqlalchemy column and Type are automatically taken from target `Model`.
* Sqlalchemy column: class of a target `Model` primary key column
* Type (used for pydantic): type of a target `Model`

####Defining `Models`:
####Defining `Models`

```Python
--8<-- "../docs_src/relations/docs002.py"
Expand All @@ -107,7 +184,7 @@ post = await Post.objects.create(title="Hello, M2M", author=guido)
news = await Category.objects.create(name="News")
```

#### Adding related models
#### add

```python
# Add a category to a post.
Expand All @@ -121,26 +198,7 @@ await news.posts.add(post)

Otherwise an IntegrityError will be raised by your database driver library.

#### create()

Create related `Model` directly from parent `Model`.

The link table is automatically populated, as well as relation ids in the database.

```python
# Creating columns object from instance:
await post.categories.create(name="Tips")
assert len(await post.categories.all()) == 2
# newly created instance already have relation persisted in the database
```

!!!note
Note that when accessing QuerySet API methods through ManyToMany relation you don't
need to use objects attribute like in normal queries.

To learn more about available QuerySet methods visit [queries][queries]

#### remove()
#### remove

Removal of the related model one by one.

Expand All @@ -150,27 +208,85 @@ Removes also the relation in the database.
await news.posts.remove(post)
```

#### clear()
#### clear

Removal all related models in one call.
Removal of all related models in one call.

Removes also the relation in the database.

```python
await news.posts.clear()
```

#### Other queryset methods
#### QuerysetProxy

Reverse relation exposes QuerysetProxy API that allows you to query related model like you would issue a normal Query.

To read which methods of QuerySet are available read below [querysetproxy][querysetproxy]

### QuerySetProxy

When access directly the related `ManyToMany` field as well as `ReverseForeignKey` returns the list of related models.

But at the same time it exposes subset of QuerySet API, so you can filter, create, select related etc related models directly from parent model.

When access directly the related `ManyToMany` field returns the list of related models.
!!!note
By default exposed QuerySet is already filtered to return only `Models` related to parent `Model`.

So if you issue `post.categories.all()` you will get all categories related to that post, not all in table.

!!!note
Note that when accessing QuerySet API methods through QuerysetProxy you don't
need to use `objects` attribute like in normal queries.

So note that it's `post.categories.all()` and **not** `post.categories.objects.all()`.

To learn more about available QuerySet methods visit [queries][queries]

!!!warning
Querying related models from ManyToMany cleans list of related models loaded on parent model:

Example: `post.categories.first()` will set post.categories to list of 1 related model -> the one returned by first()

Example 2: if post has 4 categories so `len(post.categories) == 4` calling `post.categories.limit(2).all()`
-> will load only 2 children and now `assert len(post.categories) == 2`

This happens for all QuerysetProxy methods returning data: `get`, `all` and `first` and in `get_or_create` if model already exists.

Note that value returned by `create` or created in `get_or_create` and `update_or_create`
if model does not exist will be added to relation list (not clearing it).

#### get

But at the same time it exposes full QuerySet API, so you can filter, create, select related etc.
`get(**kwargs): -> Model`

To grab just one of related models filtered by name you can use `get(**kwargs)` method.

```python
# Many to many relation exposes a list of columns models
# and an API of the Queryset:
# grab one category
assert news == await post.categories.get(name="News")

# note that method returns the category so you can grab this value
# but it also modifies list of related models in place
# so regardless of what was previously loaded on parent model
# now it has only one value -> just loaded with get() call
assert len(post.categories) == 1
assert post.categories[0] == news

```

!!!tip
Read more in queries documentation [get][get]

#### all

`all(**kwargs) -> List[Optional["Model"]]`

To get a list of related models use `all()` method.

Note that you can filter the queryset, select related, exclude fields etc. like in normal query.

```python
# with all Queryset methods - filtering, selecting columns, counting etc.
await news.posts.filter(title__contains="M2M").all()
await Category.objects.filter(posts__author=guido).get()
Expand All @@ -180,18 +296,135 @@ news_posts = await news.posts.select_related("author").all()
assert news_posts[0].author == guido
```

Currently supported methods are:
!!!tip
Read more in queries documentation [all][all]

#### create

`create(**kwargs): -> Model`

Create related `Model` directly from parent `Model`.

The link table is automatically populated, as well as relation ids in the database.

```python
# Creating columns object from instance:
await post.categories.create(name="Tips")
assert len(await post.categories.all()) == 2
# newly created instance already have relation persisted in the database
```

!!!tip
To learn more about available QuerySet methods visit [queries][queries]
Read more in queries documentation [create][create]


#### get_or_create

`get_or_create(**kwargs) -> Model`

!!!tip
Read more in queries documentation [get_or_create][get_or_create]

#### update_or_create

##### get()
##### all()
##### filter()
##### select_related()
##### limit()
##### offset()
##### count()
##### exists()
`update_or_create(**kwargs) -> Model`

[queries]: ./queries.md
!!!tip
Read more in queries documentation [update_or_create][update_or_create]

#### filter

`filter(**kwargs) -> QuerySet`

!!!tip
Read more in queries documentation [filter][filter]

#### exclude

`exclude(**kwargs) -> QuerySet`

!!!tip
Read more in queries documentation [exclude][exclude]

#### select_related

`select_related(related: Union[List, str]) -> QuerySet`

!!!tip
Read more in queries documentation [select_related][select_related]

#### prefetch_related

`prefetch_related(related: Union[List, str]) -> QuerySet`

!!!tip
Read more in queries documentation [prefetch_related][prefetch_related]

#### limit

`limit(limit_count: int) -> QuerySet`

!!!tip
Read more in queries documentation [limit][limit]

#### offset

`offset(offset: int) -> QuerySet`

!!!tip
Read more in queries documentation [offset][offset]

#### count

`count() -> int`

!!!tip
Read more in queries documentation [count][count]

#### exists

`exists() -> bool`

!!!tip
Read more in queries documentation [exists][exists]

#### fields

`fields(columns: Union[List, str, set, dict]) -> QuerySet`

!!!tip
Read more in queries documentation [fields][fields]

#### exclude_fields

`exclude_fields(columns: Union[List, str, set, dict]) -> QuerySet`

!!!tip
Read more in queries documentation [exclude_fields][exclude_fields]

#### order_by

`order_by(columns:Union[List, str]) -> QuerySet`

!!!tip
Read more in queries documentation [order_by][order_by]


[queries]: ./queries.md
[querysetproxy]: ./relations.md#querysetproxy-methods
[get]: ./queries.md#get
[all]: ./queries.md#all
[create]: ./queries.md#create
[get_or_create]: ./queries.md#get_or_create
[update_or_create]: ./queries.md#update_or_create
[filter]: ./queries.md#filter
[exclude]: ./queries.md#exclude
[select_related]: ./queries.md#select_related
[prefetch_related]: ./queries.md#prefetch_related
[limit]: ./queries.md#limit
[offset]: ./queries.md#offset
[count]: ./queries.md#count
[exists]: ./queries.md#exists
[fields]: ./queries.md#fields
[exclude_fields]: ./queries.md#exclude_fields
[order_by]: ./queries.md#order_by
Loading

0 comments on commit 3ac767e

Please sign in to comment.