Basic building blocks¶

Records¶

The simplest definition is a record. You create a named definition with some associated fields. The fields are declared within parenthesis in the form <field name> : <data type>.
record Employee {
   Id : uuid
   StartDate : date
   Name : string
}

Enumerations¶

To define a set of constant values, enum can be used. These are typically used to capture values which rarely change and where it is better than representing a value simply as a string.
enum Direction {
   North South East West
}

Entity - Uniquely identifiable objects¶

An entity distinguishes itself from a record by having an associated key.

Being able to uniquely identify an object is an important aspect in modelling. This is analogous to a primary key in relational databases. By defining an entity instead of record, you can express object identity.
entity Flight key( Id : uuid ) {
   Code : string
   Departure : time
}

Reusability¶

Keys¶

When creating an entity, instead of defining the key each time, a reusable key can be defined and used for the entity.
key AccountId {
   AccountNo : string
   SortCode : string
}

entity CurrentAccount key AccountId {
   ...
}