Constraining Entity Fields

Required

Defines whether the value of the field cannot be null.

Example of use:

entity Activity {
  name String required
}

Unique

Defines whether the field (or a list of fields) is a unique key.

There are two ways of defining a unique constraint:

Example of use:

entity DayOfWeek {
  name String unique
}

@UniqueConstraint("id, lastName")
entity Persons {
  id String
  lastName String
  firstName String
}

Min/Max bounds

Defines the min and/or the max values of a field.

Example of use:

entity {
  dayOfWeek Integer min(0) max(6)
}

Length

Defines the maximum length of a String field. Note that, by default, String fields do not have a maximum length and can contain large text data.

Example of use:

entity {
  zipCode String length(10)
}

Field type and constraint association

The following table lists the supported constraints by type.

Example of use: