An OpenAPI spec for a type that has an which is a JSON Schema

embedded-json-schema-no-allof.yaml

openapi: "3.0.2"
paths:
  /table/{tableName}:
    get:
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Table"
components:
  schemas:
    Table:
      properties:
        data_model:
          $ref: "https://json-schema.org/draft-07/schema#"
        data:
          type: array
          description: Array of rows, each adhering to the schema given in the `data_model` property
          items:
            # Each item must conform to the schema provided in the "data_model" section of this Table.
            # Not sure if this constraint can be expressed better in OpenAPI 3.0.
            type: object

embedded-json-schema.yaml

openapi: "3.0.2"
paths:
  /table/{tableName}:
    get:
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Table"
components:
  schemas:
    Table:
      properties:
        data_model:
          allOf:
            - description: A JSON Schema that defines the structure of each row in the data array
            - $ref: "https://json-schema.org/draft-07/schema#"
        data:
          type: array
          description: Array of rows, each adhering to the schema given in the `data_model` property
          items:
            # Each item must conform to the schema provided in the "data_model" section of this Table.
            # Not sure if this constraint can be expressed better in OpenAPI 3.0.
            type: object