sqldantic 0.1.0

sqlalchemy and pydantic integration.

sqldantic

SQLalchemy + pyDANTIC

Example:

from __future__ import annotations

import enum
import ipaddress 

from pydantic import BaseModel
from sqlalchemy import String, ForeignKey
from sqlalchemy.orm import Mapped
from sqlalchemy.dialects.postgresql import JSONB
from sqldantic import DeclarativeBase, Field, Relationship, Typed


class Base(DeclarativeBase):
    # see https://docs.sqlalchemy.org/en/20/orm/declarative_styles.html
    pass


class OS(str, enum.Enum):
    linux = "linux"
    windows = "windows"
    macos = "macos"
    

class Info(BaseModel):
    os: OS
    tags: set[str]
    

class ClusterBase(Base):
    name: Mapped[str]
    hosts: Mapped[list[Host]] = Relationship(back_populates="cluster")


class Cluster(ClusterBase, table=True):
    id: Mapped[int] = Field(primary_key=True)


class HostBase(Base):
    hostname: Mapped[str] = Field(index=True)
    address: Mapped[ipaddress.IPv4Address] = Field(Typed(String()))
    info: Mapped[Info] = Field(Typed(JSONB))
    cluster: Mapped[Cluster] = Relationship(back_populates="hosts")
    
    
class Host(HostBase, table=True):
    id: Mapped[int] = Field(primary_key=True)
    cluster_id: Mapped[int] = Field(ForeignKey("cluster.id"))

Descripion

Any subclass of DeclarativeBase is Pydantic Model.

Any subclass of DeclarativeBase with table=True is Sqlalchemy Model.

Both Mapped[...] and "unmapped" formats are supported, but Sqlalchemy needs Mapped for mypy type checking, so Mapped is preferred.

Sometimes it's impossible to use generic Sqlalchemy types:

class Foo(Base, table=True):
    ...
    address: Mapped[ipaddress.IPv4Address]
    info: Mapped[Info]
    ...

Both address and info are not supported by Sqlalchemy.

In such case, you can use special Typed type, which can handle any pydantic-supported types:

class Foo(Base, table=True):
    ...
    address: Mapped[ipaddress.IPv4Address] = Field(Typed(String))
    # means validate value as an IPv4Address object, but store it as a String
    info: Mapped[Info] = Field(Typed(JSONB))
    # means validate value as an Info object, but store it as a JSONB
    ...