Glossary

Mendix-specific terms and concepts for developers who are new to the Mendix platform.

A

Association A relationship between two entities. Analogous to a foreign key in relational databases. Mendix supports Reference (one-to-many or one-to-one) and ReferenceSet (many-to-many) types.

Attribute A property of an entity. Equivalent to a column in a relational database table. Types include String, Integer, Long, Decimal, Boolean, DateTime, AutoNumber, Binary, Enumeration, and HashedString.

Access Rule A security rule that controls which module roles can create, read, write, or delete instances of an entity, and which attributes they can access.

B

BSON Binary JSON. The serialization format Mendix uses to store model elements inside MPR files. Each document (entity, microflow, page, etc.) is stored as a BSON blob.

Building Block A reusable page fragment that can be dragged onto pages in Studio Pro. Similar to a Snippet but intended for the toolbox.

C

Catalog In mxcli, an in-memory SQLite database that indexes project metadata for fast querying, full-text search, and cross-reference navigation.

Constant A named value defined at the module level that can be configured per environment (development, acceptance, production). Used for API keys, URLs, feature flags, etc.

D

DataGrid A widget that displays a list of objects in a tabular format with columns, sorting, and search. The classic DataGrid uses server-side rendering; DataGrid2 is the pluggable widget version.

DataView A widget that displays a single object, providing a context for input widgets (TextBox, DatePicker, etc.) to read and write attributes.

Domain Model The data model for a module, consisting of entities, their attributes, and associations between them. Analogous to an entity-relationship diagram.

E

Entity A data type in the domain model. Equivalent to a table in a relational database. Entities can be persistent (stored in the database), non-persistent (in-memory only), or view (backed by an OQL query).

Enumeration A fixed set of named values (e.g., OrderStatus with values Draft, Active, Closed). Used as attribute types when the set of possible values is known at design time.

Event Handler Logic that runs automatically before or after a commit or delete operation on an entity. Configured on the entity in the domain model.

G

Gallery A pluggable widget that displays a list of objects in a card/tile layout, as opposed to the tabular layout of a DataGrid.

Generalization Entity inheritance. When entity B generalizes entity A, B inherits all of A’s attributes and associations. Analogous to class inheritance in object-oriented programming.

L

Layout A page template that defines the common structure (header, sidebar, footer) shared by multiple pages. Every page references a layout.

LayoutGrid A responsive grid widget based on a 12-column system. Used to create multi-column layouts with breakpoints for phone, tablet, and desktop.

M

MDL (Mendix Definition Language) A SQL-like text language for querying and modifying Mendix projects. The primary interface for mxcli.

Microflow Server-side logic expressed as a visual flow of activities. Microflows can retrieve data, call actions, make decisions, loop over lists, and return values. They run on the Mendix runtime (server).

Module A top-level organizational unit in a Mendix project. Each module contains its own domain model, microflows, pages, enumerations, and security settings. Analogous to a package or namespace.

Module Role A permission role defined within a module. Module roles are assigned to user roles at the project level. Entity access rules, microflow access, and page access are granted to module roles.

MPR Mendix Project Resource file. The binary file (.mpr) that contains the complete Mendix project model. It is a SQLite database with BSON-encoded documents.

N

Nanoflow Client-side logic that runs in the browser (or native app). Syntactically similar to microflows but with restrictions (no database transactions, limited activity types). Used for offline-capable and low-latency operations.

P

Page A user interface screen in a Mendix application. Pages contain widgets (TextBox, DataGrid, Button, etc.) and reference a layout for their outer structure.

Pluggable Widget A widget built with the Mendix Pluggable Widget API (React-based). Examples: DataGrid2, ComboBox, Gallery. Pluggable widgets use JSON-based property schemas (PropertyTypes) stored in the MPR.

R

Runtime The Mendix server-side execution environment (Java-based) that runs the application. It interprets the model, handles HTTP requests, executes microflows, and manages the database.

S

Scheduled Event A microflow that runs automatically on a timer (e.g., every hour, daily at midnight). Configured with a start time and interval.

Snippet A reusable UI fragment that can be embedded in multiple pages via a SnippetCall widget. Snippets can accept parameters.

Studio Pro The visual IDE for building Mendix applications. It reads and writes .mpr files. mxcli provides a complementary text-based interface to the same project files.

Storage Name The internal type identifier used in BSON $Type fields. Often the same as the qualified name, but not always (e.g., DomainModels$EntityImpl is the storage name for DomainModels$Entity).

U

User Role A project-level role that aggregates module roles from one or more modules. End users are assigned user roles, which determine their permissions across the entire application.

W

Widget A UI component on a page. Built-in widgets include TextBox, DataGrid, Button, Container, and LayoutGrid. Pluggable widgets extend this set with third-party components.

Workflow A long-running process with user tasks, decisions, and parallel paths. Workflows model approval processes, multi-step procedures, and human-in-the-loop automation.