https://github.com/collerek/sqlalchemy-to-ormar
Simple translator from sqlalchemy ORM models to ormar models
https://github.com/collerek/sqlalchemy-to-ormar
asyncio orm-models ormar sqlalchemy translator
Last synced: 8 months ago
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Simple translator from sqlalchemy ORM models to ormar models
- Host: GitHub
- URL: https://github.com/collerek/sqlalchemy-to-ormar
- Owner: collerek
- License: mit
- Created: 2021-04-06T16:24:03.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2021-05-16T14:12:22.000Z (over 4 years ago)
- Last Synced: 2024-09-07T04:10:41.910Z (about 1 year ago)
- Topics: asyncio, orm-models, ormar, sqlalchemy, translator
- Language: Python
- Homepage:
- Size: 35.2 KB
- Stars: 12
- Watchers: 1
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE.md
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README
# sqlalchemy-to-ormar
A simple auto-translator from `sqlalchemy` ORM models to `ormar` models.
The `ormar` package is an async mini ORM for Python, with support for **Postgres,
MySQL**, and **SQLite**.
To learn more about ormar:
* ormar [github][github]
* ormar [documentation][documentation]
## Quickstart
```python
from databases import Database
from sqlalchemy import (
Column,
ForeignKey,
Integer,
MetaData,
String,
create_engine,
DECIMAL,
)
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import Session, relationship, sessionmaker
Base = declarative_base()
Database_URL = "sqlite:///test.db"
engine = create_engine(Database_URL, echo=True)
# given sqlalchemy models you already have
class User(Base):
__tablename__ = "users"
id = Column(Integer, primary_key=True)
name = Column(String)
fullname = Column(String)
nickname = Column(String)
salary = Column(DECIMAL)
addresses = relationship(
"Address", back_populates="user", cascade="all, delete, delete-orphan"
)
class Address(Base):
__tablename__ = "addresses"
id = Column(Integer, primary_key=True)
email_address = Column(String, nullable=False)
user_id = Column(Integer, ForeignKey("users.id"))
user = relationship("User", back_populates="addresses")
# instantiate new Databases instance
database = Database(Database_URL)
# note that you need new metadata instance as table names in ormar
# will remain the same and you cannot have two tables with same name in
# one metadata, note that we bind it to the same engine!
# (or you can create new one with same url)
metadata = MetaData(engine)
# use sqlalchemy-to-ormar (not normally imports should be at the top)
from sqlalchemy_to_ormar import ormar_model_str_repr, sqlalchemy_to_ormar
# convert sqlalchemy models to ormar
OrmarAddress = sqlalchemy_to_ormar(Address, database=database, metadata=metadata)
OrmarUser = sqlalchemy_to_ormar(User, database=database, metadata=metadata)
# you can print the ormar model
# or save it to file and you have proper model definition created for you
address_str = ormar_model_str_repr(OrmarAddress)
# now you can print it or save to file
print(address_str)
# will print:
# class OrmarAddress(ormar.Model):
#
# class Meta(ormar.ModelMeta):
# metadata=metadata
# database=database
# tablename="addresses"
#
# id = ormar.Integer(autoincrement=True, primary_key=True)
# email_address = ormar.String(max_length=255, nullable=False)
# user = ormar.ForeignKey(to=OrmarUser, related_name="addresses", name=user_id, nullable=True)
# if you want to skip column aliases if they match field names use skip_names_if_match flag
user_model_str = ormar_model_str_repr(OrmarUser, skip_names_if_match=True)
# let's insert some sample data with sync sqlalchemy
Base.metadata.create_all(engine)
LocalSession = sessionmaker(bind=engine)
db: Session = LocalSession()
ed_user = User(name="ed", fullname="Ed Jones", nickname="edsnickname")
address = Address(email_address="ed@example.com")
address2 = Address(email_address="eddy@example.com")
ed_user.addresses = [address, address2]
db.add(ed_user)
db.commit()
# and now we can query it asynchronously with ormar
async def test_ormar_queries():
user = await OrmarUser.objects.select_related("addresses").get(name='ed')
assert len(user.addresses) == 2
assert user.nickname == 'edsnickname'
assert user.fullname == 'Ed Jones'
addresses = await OrmarAddress.objects.select_related('user').all(user__name='ed')
assert len(addresses) == 2
assert addresses[0].user.nickname == 'edsnickname'
assert addresses[1].user.nickname == 'edsnickname'
# run async
import asyncio
asyncio.run(test_ormar_queries())
# drop db
Base.metadata.drop_all(engine)
```
## Automap support
You can use [`sqlacodegen`](https://github.com/agronholm/sqlacodegen) to generate sqlalchemy models out of existing database
and then use sqlalchemy-to-ormar to translate it to `ormar` models.
Note that sqlalchemy has it's own automap feature, but out of experience it does not work well with complicated databases.
## Supported fields
`sqlalchemy-to-ormar` supports following sqlalchemy field types:
* "integer": `ormar.Integer`,
* "small_integer": `ormar.Integer`,
* "big_integer": `ormar.BigInteger`,
* "string": `ormar.String,`
* "text": `ormar.Text,`
* "float": `ormar.Float,`
* "decimal": `ormar.Decimal,`
* "date": `ormar.Date,`
* "datetime": `ormar.DateTime,`
* "time": `ormar.Time,`
* "boolean": `ormar.Boolean`
## Supported relations
sqlalchemy-to-ormar supports both `ForeignKey` as well as `ManyToMany` relations
although like `ormar` itself it will create relation field on one side of the relation only
and other side will be auto-populated with reversed side.
## Known limitations
sqlalchemy to ormar right now does not support:
* composite (multi-column) primary keys and foreign keys (as ormar does not support them
yet)
* `cascade` options from `relationship` are ignored, only the ones declared in sqlalchemy ForeignKey (ondelete, onupdate) are extracted
* ManyToMany fields names customization (as ormar does not support them yet)
* ManyToMany association table has to have primary key
* Model inheritance
[documentation]: https://collerek.github.io/ormar/
[github]: https://github.com/collerek/ormar