V. Validation layer

The validation layer provides a set of predicates used in the property validation process. Predicates rely on descriptive definitions encoded at the ontology level, allowing an ad-hoc validation of data. To make things even easier to instantiate there are predefined predicates associated with all primitive concepts (Numeric, String, etc.).

{
  "$type": "validation",
  "$version": "1.0",
  "$schema": "A01564DBBCB04816A9BFE5FB50723EFD3BBE119E",
  "$id": "DA4B9237BACCCDF19C0760CAB7AEC4A8359010B0",
  "$author": "Andrei",
  "$description": "Provide properties value validation",
  "validations": {
    "name": {
      "regex": "[a-zA-Z0-9]",
      "max-length": "200"
    },
    "age": {
      "required": true,
      "range": "1:150"
    },
    "address": {
      "required": true
    },
    "email": {
      "regex": "/S+@S+.S+/"
    },
    "password": {
      "required": true
    },
    "lastSeen": {
      "date": "DD/MM/YYYY"
    }
  }
}

From a conceptual perspective, the validation rules are constructed based on a set of predefined predicates that are fixed rules defined at the ontology level. These predicates are specific to the definition domain and are mainly defined for primitive data types (e.g. regex, max-length, max, min, range, etc.).

The targeted concept and the container ontology is defined in the model header. The validations collection aggregates validators for all properties relating to the concept. Each property can have zero or multiple validation rules attached.

Validation rule schema contains two pieces of information: the predicate type and the predicate parameters. A predicate parameter represents the needed parameter for a specific predicate; it does not have a strict format because it depends on the used predicate.

Supported validations

Name	Description
required	Enforce a field as obligatory; otherwise, display an error message.
minLength	Enforce a minimum character length constraint on a field; otherwise, display an error message.
maxLength	Enforce a maximum character length constraint on a field; otherwise, display an error message.
min	Enforce a minimum value constraint on a field; otherwise, display an error message.
max	Enforce a maximum value constraint on a field; otherwise, display an error message.
email	Validate the field to ensure it contains a properly formatted email address; otherwise, display an error message.
regex	Apply a regular expression pattern to the field for validation; otherwise, display an error message.
date	Validate the field for proper date formatting; otherwise, display an error message.
range	Ensure the field value falls within a specified range; otherwise, display an error message.
content-type	Validating files based on their mime type.