Core: introduction

As stated in the Architecture:

Core functionality is considered functionality that does not or very loosely tie in to particular modules. It is functionality that has meaning on its own without dependencies, but is enriched by modules.

The core really implements the “engine” of Open Forms and hides all the implementation details. It should be fairly stable, but also continually allow for new feature additions, which is a challenging task!

The following Django apps are considered core functionality:

• openforms.accounts: (staff) user account management

• openforms.config: application-wide configuration and defaults

• openforms.forms: designing and building of forms

• openforms.formio: integration with the form.io frontend library

• openforms.submissions: persisting and handling of submitted form data

• openforms.variables: persisting (intermediate) data into variables for further operations

Data model

The following is a simplified relationship diagram of the Django models that relates to forms:

        ---
Forms model relationship
---
erDiagram
Category {
    UUIDField uuid
    CharField path
    CharField name
}
Form {
    UUIDField uuid
    SlugField slug
    CharField name
    ForeignKey category
}
FormDefinition {
    UUIDField uuid
    CharField name
    SlugField slug
    JSONField configuration
    BooleanField login_required
    BooleanField is_reusable
}
FormStep {
    UUIDField uuid
    SlugField slug
    ForeignKey form
    ForeignKey form_definition
    BooleanField is_applicable
}
FormVariable {
    ForeignKey form
    ForeignKey form_definition
    TextField name
    TextField key
    CharField source
    CharField data_type
    CharField data_subtype
    CharField data_format
    BooleanField is_sensitive_data
    JSONField initial_value
}
Form }|--|| Category : category
FormStep }|--|| Form : form
FormStep }|--|| FormDefinition : form_definition
FormVariable }|--|| Form : form
FormVariable }|--|| FormDefinition : form_definition

    

Each Form can have multiple FormStep’s defined, which acts as a proxy model to a FormDefinition (as these can be reusable across forms). The FormDefinition model has a configuration JSON field, holding the form.io configuration.

The submissions data model mirrors this model in some way:

• A Submission is tied to a Form.

• A SubmissionStep is tied to a FormStep.

• A SubmissionValueVariable is tied to a FormVariable.