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Unified Modelling Schema

Getting started

Unified Modelling Schema (UMS) is a YAML representation of a data model. It preserves implementation structure—types, properties, keys, and relationships—and the domain statements that explain what that structure means.

Model a small domain

Section titled “Model a small domain”

Start by identifying the things in the domain and the facts that connect them. The following model says that a person has a login name and that a person can like a film.

- Type: Person
  Labels:
    - Person
  PrimaryKey:
    - Person_Id
  Properties:
    - Name: Person_Id
      DataType: Integer
      Constraints:
        - NOT NULL
    - Name: LoginName
      DataType: TextVariableLength
      Length: 100
      Constraints:
        - NOT NULL
        - UNIQUE
      FactTypeReadings:
        - Language: English
          Readings:
            - {Person} has {LoginName}
            - {LoginName} is of {Person}
  IsRelationshipType: false


- Type: PersonLikesFilm
  Label: LIKES
  Source: Person
  Target: Film
  RelationshipAnnotation: {Person} likes {Film}
  PrimaryKey:
    - Person_Id
    - Film_Id
  Relationships:
    - Name: PersonPersonLikesFilm
      Source: PersonLikesFilm
      Target: Person
      From:
        - Person_Id
      To:
        - Person_Id
      Readings:
        - {PersonLikesFilm} involves {Person}
    - Name: FilmPersonLikesFilm
      Source: PersonLikesFilm
      Target: Film
      From:
        - Film_Id
      To:
        - Film_Id
      Readings:
        - {PersonLikesFilm} involves {Film}
  FactTypeReadings:
    - Language: English
      Readings:
        - {Person} likes {Film}
  IsRelationshipType: true

Read the model

Section titled “Read the model”
  • A type is a domain concept. It is an entity type when IsRelationshipType is false, and an association type when it is true.
  • A property has a portable UMS datatype and can carry constraints such as NOT NULL and UNIQUE.
  • A relationship maps fields on the source type (From) to fields on the target type (To). Keep both lists in the same order.
  • A fact type reading records the domain statement in a named language. Use short, natural sentences that a subject-matter expert can verify.

Choose an implementation view

Section titled “Choose an implementation view”

UMS does not require a physical storage choice at modelling time. Once the model is sound, use the reference for your implementation style: