Composite IndexΒΆ

Composite indexes are indexes that span multiple columns.

See also

Composite Index

OpenAlchemy documentation for composite indexes.

SQLAlchemy Composite Index

Documentation for defining composite indexes in SQLAlchemy.

The following example defines a composite index for the Employee schema over the name and division property:

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openapi: "3.0.0"

info:
  title: Test Schema
  description: API to illustrate the OpenAlchemy composite index feature.
  version: "0.1"

paths:
  /employee:
    get:
      summary: Used to retrieve all employees.
      responses:
        200:
          description: Return all employees from the database.
          content:
            application/json:
              schema:
                type: array
                items:
                  "$ref": "#/components/schemas/Employee"

components:
  schemas:
    Employee:
      description: Person that works for a company.
      type: object
      x-tablename: employee
      properties:
        id:
          type: integer
          description: Unique identifier for the employee.
          example: 0
          x-primary-key: true
        name:
          type: string
          description: The name of the employee.
          example: David Andersson
        division:
          type: string
          description: The part of the company the employee works in.
          example: Engineering
      x-composite-index:
        - name
        - division

The following file uses OpenAlchemy to generate the SQLAlchemy models:

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from open_alchemy import init_yaml

init_yaml("example-spec.yml", models_filename="models_auto.py")

The SQLAlchemy models generated by OpenAlchemy are equivalent to the following traditional models file:

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import sqlalchemy as sa
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()


class Employee(Base):
    """Person that works for a company."""

    __tablename__ = "employee"
    id = sa.Column(sa.Integer, primary_key=True)
    name = sa.Column(sa.String)
    division = sa.Column(sa.String)


sa.Index(None, Employee.name, Employee.division)

OpenAlchemy will generate the following typed models:

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"""Autogenerated SQLAlchemy models based on OpenAlchemy models."""
# pylint: disable=no-member,super-init-not-called,unused-argument

import typing

import sqlalchemy
from sqlalchemy import orm

from open_alchemy import models

Base = models.Base  # type: ignore


class EmployeeDict(typing.TypedDict, total=False):
    """TypedDict for properties that are not required."""

    id: typing.Optional[int]
    name: typing.Optional[str]
    division: typing.Optional[str]


class TEmployee(typing.Protocol):
    """
    SQLAlchemy model protocol.

    Person that works for a company.

    Attrs:
        id: Unique identifier for the employee.
        name: The name of the employee.
        division: The part of the company the employee works in.

    """

    # SQLAlchemy properties
    __table__: sqlalchemy.Table
    __tablename__: str
    query: orm.Query

    # Model properties
    id: "sqlalchemy.Column[typing.Optional[int]]"
    name: "sqlalchemy.Column[typing.Optional[str]]"
    division: "sqlalchemy.Column[typing.Optional[str]]"

    def __init__(
        self,
        id: typing.Optional[int] = None,
        name: typing.Optional[str] = None,
        division: typing.Optional[str] = None,
    ) -> None:
        """
        Construct.

        Args:
            id: Unique identifier for the employee.
            name: The name of the employee.
            division: The part of the company the employee works in.

        """
        ...

    @classmethod
    def from_dict(
        cls,
        id: typing.Optional[int] = None,
        name: typing.Optional[str] = None,
        division: typing.Optional[str] = None,
    ) -> "TEmployee":
        """
        Construct from a dictionary (eg. a POST payload).

        Args:
            id: Unique identifier for the employee.
            name: The name of the employee.
            division: The part of the company the employee works in.

        Returns:
            Model instance based on the dictionary.

        """
        ...

    @classmethod
    def from_str(cls, value: str) -> "TEmployee":
        """
        Construct from a JSON string (eg. a POST payload).

        Returns:
            Model instance based on the JSON string.

        """
        ...

    def to_dict(self) -> EmployeeDict:
        """
        Convert to a dictionary (eg. to send back for a GET request).

        Returns:
            Dictionary based on the model instance.

        """
        ...

    def to_str(self) -> str:
        """
        Convert to a JSON string (eg. to send back for a GET request).

        Returns:
            JSON string based on the model instance.

        """
        ...


Employee: typing.Type[TEmployee] = models.Employee  # type: ignore

See also

Getting Started