Models

Models within Centurion ERP are how the data is structured within the database. This page contains documentation pertinent to the development of the models for use with Centurion ERP.

Creating a Model

All models are class based models. Due to this fact, most of the work has been done for the models. We have two types of models: normal and sub-model. In most cases to create a model you will only need to declare the fields and any validation.

When designing or even implementing a model do consider that what is defined within its class must take into account that the model is responsible for ensure that no data is saved to the database wherein it could create an inconsistancy. For ensureing this does not see Validation below.

Requirements

When creating models they must meet the following requirements:

inherits from core.models.centurion.CenturionModel or if a submodel core.models.centurion.CenturionSubModel and its base model.
class has the folloing objects defined:
- Function __str__ is defined to return the models name when requested as a string.
- Attribute page_layout is defined with the models UI page layout
- Attribute table_fields is defined with the fields to display by default for viewing the model within a table.
Fields are initialized with the following parameters:
- verbose_name
- help_text
contains a Meta sub-class with following attributes:
- ordering Order the results are returned in.
- verbose_name Name of the Model.
- verbose_name_plural Plural Name of the model
No queryset is to return data that the user has not got access to.
Model Exceptions must be from django.core.exceptions

Tip

It's a good idea to create the initial model class, then create and add the model tests for that class. This way you can run the tests to ensure that the requirements are met. Of Note, the tests may not cover ALL of the requirements section, due diligence will need to be exercised.

Normal (Base) Model

This model is nothing special and is the core model type that will be created. If this model is inherited by a sub-model its also referred to as a "base model." Creating one is as simple as simple as declaring the class, inheriting from core.models.centurion.CenturionModel then adding your fields and validation method(s).

Available Base models

The are already some base models within Centurion ERP that you can use to extend and/or add features to Centurion easier. They are:

Asset
- ITAM Asset
  
  A sub-model of Asset. Used by the ITAM module
Entity
- Company
  
  A sub-model of Entity. All business like entities
- Person
  
  A sub-model of Entity. As the name implies, A person
  - Contact
    
    A sub-model of Person. Contains fields that are common to a contact
Ticket

All Ticketing Models use this
Ticket Comment

All Ticket Comment Models use this

All sub-models are intended to be extended and contain the core features for ALL models. This aids in extensibility and reduces the work required to add a model.

Tip

Core features can be switched on and/or off for the model you are creating. Before doing so though, consider the reasons for doing so and do discuss with a maintainer. This discussion will be required to ensure that you are not unintentially removing a feature that is a must for a Centurion ERP model.

Sub-Model

A Sub-model specifically inherits from a normal model with the purpose of using the base model fields (the common fields) and if required specifying its own fields. A sub-model provides an additional feature in that the data from the base model can now be based off of the permissions of the sub-model, not the base. THis model inherits from core.models.centurion.CenturionSubModel and its base model.

Core Features

All models must contain the core features, being:

Audit History

Every change that occurs to a model is recorded
Notes

Adds the ability for a user to add comments to a model
KB Article linking

Enables linking a knowledge base article to a model
Model Tag

Enables the possibility within markdown fields to use its tag to create a link to the model.

Validation Methods

Within All of our models including when they are created via an API serializer, the models validators are called. The models validators are responsible for ensuring that no data goes into the database that may create an inconsistancy.

Example

You have defined a model that has a user field that must always have a value. This model can be access via the API, in which the user field is auto-populated by object request.user. In the same token you have admin commands that uses this model. Now every time you use the admin command to create this model, it will fail validation due to there being no value for the user field. This is where the models validator methods come into play. defining method clean() within the model with the logic required to ensure that the user field has value for the user field ensures that the model now when used by the admin command is consistant and meets the intent of the models purpose.

Whilst most data that will use a model will be via an API Serializer, which in turn has its own validation. The models Validation is only to serve the purpose of ensuring data consistancy.

page_layout Attribute

Within the model attributes, page_layout is required. This attribute is what the UI uses to render the page. simply put, it's the layout of the page. Currently this layout is for a models details page only.

The page_layout attribute is a python list that is broken down into dictionaries for the page tabs, which then contain the page sections. Breakdown of the page layout is as follows:

Tab These are the tabs at the top of a models details page. A tab contains sections.
Section The page is broken down horizontially into sections. A section contains columns or a table.
Column Vertical breakdown of a section. A column contains fields.
Table A table is a layout for a section. The table renders a sub-model as part of the existing models information.

Example of ALL available options for the page_layout attribute.

page_layout: list = [
    {    # Detail Tab.
        "name": "Details",    # Tab name.
        "slug": "details",    # HTML id field.
        "sections": [    # Page Sections.
            {    # double column section.
                "layout": "double",
                "left": [    # Left column. This list is a list of fields that match the serializer fields.
                    'organization',
                    'name',
                    'is_global',
                ],
                "right": [    # right column. This list is a list of fields that match the serializer fields.
                    'model_notes',
                    'created',
                    'modified',
                ]
            },
            {    # Table Section.
                "layout": "table",
                "name": "Dependent Services",    # Heading for the section.
                "field": "service",    # field name within the `_urls` dict of the api query. which is where the data will be fetched from.
            },
            {    # single column section.
                "layout": "single",
                "fields": [    # This list is a list of fields that match the serializer fields.
                    'config',
                ]
            }
        ]
    },
    {    # Notes Tab.
        "name": "Notes",
        "slug": "notes",
        "sections": []    # The notes tab is a special case that requires no sections to be defined.
    },
]

table_fields Attributes

The table_fields attribute within a model is what the UI List View or section table uses as the fields to add to the table. The table_fields attribute is a python list of string/dictionary that are the field names as are defined within the serializer. If the field is defined as a dictionary, the field is formatted as per the definition. for example:

table_fields: list = [
    'organization',
    'name'
    {
        'field': 'display_name',    # String, Name of the field to use
        'type': 'link',             # Choice, (link = anchor link) definition type
        'key': '_self'              # String, Dictionary key to use, in case of link. in this case will expand to `_urls._self`
    },
    'created'
]

Depreciated Docs undergoing re-write

ToDo
- Avoid:
  - adding model.delete() method
  - adding model.save() method
- Do
  - Add model.clean() To set/modify any field values, if required

Requirements

clean() method within a model is only used to ensure that the data entered into the DB is valid and/or to ensure application wide changes/validation is conducted prior to saving model.
Tenancy models must have the ability to have a knowledge base article linked to it.
Models must save audit history

Requirements

Must not be an abstract class
Attribute sub_model_type must be specified within the models Meta sub-class
File name is <base model>_<sub_model_type> where base model is the value of Meta.sub_model_type or the first model in the chain.

Checklist

This section details the additional items that may need to be done when adding a new model:

If the model is a primary model, add it to model reference rendering in app/core/lib/markdown_plugins/model_reference.py function tag_html
If the model is a primary model, add it to the model link slash command in app/core/lib/slash_commands/linked_model.py function command_linked_model

History

Adding History to a model is automatic. If there is a desire not to have model history it can be disabled by adding attribute _audit_enabled to the model class and setting its value to False.

Tests

The following Unit test suites exists for models:

Unit Tests
- model (Base Model) core.tests.unit.centurion_abstract.test_unit_centurion_abstract_model.CenturionAbstractModelInheritedCases
- model (Sub-Model) core.tests.unit.centurion_sub_abstract.test_unit_centurion_sub_abstract_model.CenturionSubAbstractModelInheritedCases
Functional Tests
- model core.tests.functional.centurion_abstract.test_functional_centurion_abstract_model.CenturionAbstractModelInheritedCases
- API Fields Render api.tests.functional.test_functional_api_fields.APIFieldsInheritedCases

Info

If you add a feature you will have to write the test cases for that feature if they are not covered by existing test cases.

Each model has the following Test Suites auto-magic created:

API Permissions checks api.tests.functional.test_functional_meta_permissions_api

Checks the CRUD permissions against the models API endpoints
Audit History Model checks, core.tests.unit.centurion_audit_meta.test_unit_meta_audit_history_model

Confirms the model has a AuditHistory model and other checks as required for an AuditHistory model.

These auto-magic tests require no input and will be created on a model inheriting from CenturionModel and run every time the tests are run.

Knowledge Base Article linking

All Tenancy Models must have the ability to be able to have a knowledge base article linked to it. To do so the following must be done:

Add to the serializer as part of dictionary _urls key knowledge_base that resolves to the article url.

def get_url(self, obj) -> dict:

    return {
        '_self': ...,
        'knowledge_base': reverse(
            "v2:_api_v2_model_kb-list",
            request=self._context['view'].request,
            kwargs={
                'model': self.Meta.model._meta.model_name,
                'model_pk': item.pk
            }
        ),
    }

Add to the models page_layout attirubute a tab called Knowledge Base

page_layout: dict = [
    {
        "name": "Knowledge Base",
        "slug": "kb_articles",
        "sections": [
            {
                "layout": "table",
                "field": "knowledge_base",
            }
        ]
    },
]

About:

This page forms part of our Project Centurion ERP.

Page Metadata

Version: ToDo: place files short git commit here
Date Created: 2024-07-14
Date Edited: 2025-05-31

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