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fix inherited pk and add field accessor access to relations

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collerek
2021-06-25 13:32:31 +02:00
parent cc76e9b862
commit 107404c3e8
10 changed files with 516 additions and 61 deletions
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@ -79,7 +79,27 @@ Ormar is built with:
As I write open-source code to solve everyday problems in my work or to promote and build strong python
community you can say thank you and buy me a coffee or sponsor me with a monthly amount to help ensure my work remains free and maintained.
<iframe src="https://github.com/sponsors/collerek/button" title="Sponsor collerek" height="35" width="116" style="border: 0;"></iframe>
<a aria-label="Sponsor collerek" href="https://github.com/sponsors/collerek" style="text-decoration: none; color: #c9d1d9 !important;">
<div style="
background-color: #21262d;
border-color: #30363d;
box-shadow: 0 0 transparent, 0 0 transparent;
color: #c9d1d9 !important;
border: 1px solid;
border-radius: 6px;
cursor: pointer;
display: inline-block;
font-size: 14px;
padding: 10px;
line-height: 0px;
height: 40px;
">
<svg aria-hidden="true" viewBox="0 0 16 16" height="16" width="16" style="fill: #db61a2">
<path fill-rule="evenodd" d="M4.25 2.5c-1.336 0-2.75 1.164-2.75 3 0 2.15 1.58 4.144 3.365 5.682A20.565 20.565 0 008 13.393a20.561 20.561 0 003.135-2.211C12.92 9.644 14.5 7.65 14.5 5.5c0-1.836-1.414-3-2.75-3-1.373 0-2.609.986-3.029 2.456a.75.75 0 01-1.442 0C6.859 3.486 5.623 2.5 4.25 2.5zM8 14.25l-.345.666-.002-.001-.006-.003-.018-.01a7.643 7.643 0 01-.31-.17 22.075 22.075 0 01-3.434-2.414C2.045 10.731 0 8.35 0 5.5 0 2.836 2.086 1 4.25 1 5.797 1 7.153 1.802 8 3.02 8.847 1.802 10.203 1 11.75 1 13.914 1 16 2.836 16 5.5c0 2.85-2.045 5.231-3.885 6.818a22.08 22.08 0 01-3.744 2.584l-.018.01-.006.003h-.002L8 14.25zm0 0l.345.666a.752.752 0 01-.69 0L8 14.25z"></path>
</svg>
<span style="color: #c9d1d9 !important;">Sponsor</span>
</div>
</a>
### Migrating from `sqlalchemy` and existing databases
@ -176,6 +196,7 @@ class BaseMeta(ormar.ModelMeta):
# id = ormar.Integer(primary_key=True) # <= notice no field types
# name = ormar.String(max_length=100)
class Author(ormar.Model):
class Meta(BaseMeta):
tablename = "authors"
@ -210,15 +231,9 @@ async def create():
# Create some records to work with through QuerySet.create method.
# Note that queryset is exposed on each Model's class as objects
tolkien = await Author.objects.create(name="J.R.R. Tolkien")
await Book.objects.create(author=tolkien,
title="The Hobbit",
year=1937)
await Book.objects.create(author=tolkien,
title="The Lord of the Rings",
year=1955)
await Book.objects.create(author=tolkien,
title="The Silmarillion",
year=1977)
await Book.objects.create(author=tolkien, title="The Hobbit", year=1937)
await Book.objects.create(author=tolkien, title="The Lord of the Rings", year=1955)
await Book.objects.create(author=tolkien, title="The Silmarillion", year=1977)
# alternative creation of object divided into 2 steps
sapkowski = Author(name="Andrzej Sapkowski")
@ -317,27 +332,43 @@ async def delete():
# note that despite the fact that record no longer exists in database
# the object above is still accessible and you can use it (and i.e. save()) again.
tolkien = silmarillion.author
await Book.objects.create(author=tolkien,
title="The Silmarillion",
year=1977)
await Book.objects.create(author=tolkien, title="The Silmarillion", year=1977)
async def joins():
# Tho join two models use select_related
# Django style
book = await Book.objects.select_related("author").get(title="The Hobbit")
# Python style
book = await Book.objects.select_related(Book.author).get(
Book.title == "The Hobbit"
)
# now the author is already prefetched
assert book.author.name == "J.R.R. Tolkien"
# By default you also get a second side of the relation
# constructed as lowercase source model name +'s' (books in this case)
# you can also provide custom name with parameter related_name
# Django style
author = await Author.objects.select_related("books").all(name="J.R.R. Tolkien")
# Python style
author = await Author.objects.select_related(Author.books).all(
Author.name == "J.R.R. Tolkien"
)
assert len(author[0].books) == 3
# for reverse and many to many relations you can also prefetch_related
# that executes a separate query for each of related models
# Django style
author = await Author.objects.prefetch_related("books").get(name="J.R.R. Tolkien")
# Python style
author = await Author.objects.prefetch_related(Author.books).get(
Author.name == "J.R.R. Tolkien"
)
assert len(author.books) == 3
# to read more about relations
@ -371,11 +402,17 @@ async def filter_and_sort():
# to sort decreasing use hyphen before the field name
# same as with filter you can use double underscores to access related fields
# Django style
books = await Book.objects.filter(author__name__icontains="tolkien").order_by(
"-year").all()
books = (
await Book.objects.filter(author__name__icontains="tolkien")
.order_by("-year")
.all()
)
# python style
books = await Book.objects.filter(Book.author.name.icontains("tolkien")).order_by(
Book.year.desc()).all()
books = (
await Book.objects.filter(Book.author.name.icontains("tolkien"))
.order_by(Book.year.desc())
.all()
)
assert len(books) == 3
assert books[0].title == "The Silmarillion"
assert books[2].title == "The Hobbit"
@ -448,25 +485,68 @@ async def aggregations():
# count:
assert 2 == await Author.objects.count()
# exists:
# exists
assert await Book.objects.filter(title="The Hobbit").exists()
# max:
# maximum
assert 1990 == await Book.objects.max(columns=["year"])
# min:
# minimum
assert 1937 == await Book.objects.min(columns=["year"])
# avg:
# average
assert 1964.75 == await Book.objects.avg(columns=["year"])
# sum:
# sum
assert 7859 == await Book.objects.sum(columns=["year"])
# to read more about aggregated functions
# visit: https://collerek.github.io/ormar/queries/aggregations/
async def raw_data():
# extract raw data in a form of dicts or tuples
# note that this skips the validation(!) as models are
# not created from parsed data
# get list of objects as dicts
assert await Book.objects.values() == [
{"id": 1, "author": 1, "title": "The Hobbit", "year": 1937},
{"id": 2, "author": 1, "title": "The Lord of the Rings", "year": 1955},
{"id": 4, "author": 2, "title": "The Witcher", "year": 1990},
{"id": 5, "author": 1, "title": "The Silmarillion", "year": 1977},
]
# get list of objects as tuples
assert await Book.objects.values_list() == [
(1, 1, "The Hobbit", 1937),
(2, 1, "The Lord of the Rings", 1955),
(4, 2, "The Witcher", 1990),
(5, 1, "The Silmarillion", 1977),
]
# filter data - note how you always get a list
assert await Book.objects.filter(title="The Hobbit").values() == [
{"id": 1, "author": 1, "title": "The Hobbit", "year": 1937}
]
# select only wanted fields
assert await Book.objects.filter(title="The Hobbit").values(["id", "title"]) == [
{"id": 1, "title": "The Hobbit"}
]
# if you select only one column you could flatten it with values_list
assert await Book.objects.values_list("title", flatten=True) == [
"The Hobbit",
"The Lord of the Rings",
"The Witcher",
"The Silmarillion",
]
# to read more about extracting raw values
# visit: https://collerek.github.io/ormar/queries/aggregations/
async def with_connect(function):
# note that for any other backend than sqlite you actually need to
# connect to the database to perform db operations
@ -477,15 +557,25 @@ async def with_connect(function):
# in your endpoints but have a global connection pool
# check https://collerek.github.io/ormar/fastapi/ and section with db connection
# gather and execute all functions
# note - normally import should be at the beginning of the file
import asyncio
# note that normally you use gather() function to run several functions
# concurrently but we actually modify the data and we rely on the order of functions
for func in [create, read, update, delete, joins,
filter_and_sort, subset_of_columns,
pagination, aggregations]:
for func in [
create,
read,
update,
delete,
joins,
filter_and_sort,
subset_of_columns,
pagination,
aggregations,
raw_data,
]:
print(f"Executing: {func.__name__}")
asyncio.run(with_connect(func))
@ -523,6 +613,8 @@ metadata.drop_all(engine)
* `fields(columns: Union[List, str, set, dict]) -> QuerySet`
* `exclude_fields(columns: Union[List, str, set, dict]) -> QuerySet`
* `order_by(columns:Union[List, str]) -> QuerySet`
* `values(fields: Union[List, str, Set, Dict])`
* `values_list(fields: Union[List, str, Set, Dict])`
#### Relation types
@ -584,6 +676,10 @@ Signals allow to trigger your function for a given event on a given Model.
* `post_update`
* `pre_delete`
* `post_delete`
* `pre_relation_add`
* `post_relation_add`
* `pre_relation_remove`
* `post_relation_remove`
[sqlalchemy-core]: https://docs.sqlalchemy.org/en/latest/core/