Mendix Advanced Developer key terms

An inheritance relationship in the domain model where a specialized entity inherits all attributes and associations of a parent entity. Retrieving the parent returns instances of every specialization, so shared logic can be written once.

An entity whose objects live only in memory and are never written to the database. Used for calculated results, temporary selections, and data passed between microflows; values disappear when the object is garbage collected.

The end of an association whose entity stores the reference to the other entity in its database table. The owner determines where the foreign key lives and which side is loaded first during retrieval.

An attribute whose value is produced by a microflow instead of being entered by the user. Mendix recalculates it whenever an object is committed, and the microflow must return a value of the defined type.

A microflow or Java action bound to an entity event - before or after create, commit, or delete - that runs automatically for every object of that entity, whichever microflow triggered the change.

A declarative filter written in Mendix XPath syntax that selects which objects a retrieve, data widget, or access rule may return. The runtime translates it into SQL, so its shape strongly affects database performance.

The built-in module shipped with every app. It contains reusable entities such as System.User, System.FileDocument, and System.Image, and the runtime uses them for accounts, file handling, and scheduled events.

A per-entity, per-module-role permission set defining create, read, update, and delete rights, plus member-level access and an optional XPath constraint that limits which rows the role can see.

A role defined inside one module that groups the entity and microflow permissions that module exposes. Module roles are mapped to app-level user roles, and several module roles can map to one user role.

A condition attached to an entity access rule that filters rows for a module role at the database level. It is appended to every query the role runs, giving row-level security without extra microflow logic.

The security level used for live apps. It requires users to sign in with a configured authentication method, enforces the role-based access model, and disables demo users.

A test account with a password and a set of user roles defined in the project security settings, available only when the security level is Prototype. Demo users let developers switch roles while testing.

A server-side visual program that runs in the runtime and can touch the database, call web services, and use Java actions. It handles business logic, scheduled work, and anything requiring transactional persistence.

A client-side visual program that runs in the browser or device and works with objects already loaded in the client. Nanoflows cannot run database queries directly and suit responsive UI logic and offline apps.

A microflow element that catches a failing activity and routes execution to an alternative flow. It can continue with a custom error type or rethrow, and it determines whether previous changes are rolled back.

An entity-level check on one or more attributes, with a message shown to the user, evaluated when the object is committed or when the rule is triggered explicitly. Failed rules block the commit by raising a validation error.

An activity that writes the changes on an object to the database and fires the entity's before- and after-commit event handlers. Uncommitted changes exist only in runtime memory and are lost on rollback.

A module document describing an external REST API: base URL, authentication, operations, and request and response handling. Microflows call its operations through a Call REST service activity generated from that definition.

A mapping document that converts an incoming JSON or XML message into Mendix objects, using a message definition to describe the structure and optionally a microflow to post-process the result.

A mapping document that converts Mendix objects into a JSON or XML message body based on a message definition. It is used when sending data through REST, SOAP, or file exports.

A module document that exposes microflows as HTTP endpoints with paths, HTTP methods, parameters, and response codes. It lets external systems call app logic without exposing the database schema.

A service that exposes entities and their associations as an OData feed, with authentication and per-entity read or write access controlled by the publishing configuration and the entity access rules.

A document holding an XML schema or JSON structure that describes the shape of an external message. Import and export mappings reference it to validate structure and to generate the mapping tree.

A database index created on one or more attributes of a persistent entity to speed up retrieves, sorts, and joins. Indexes make reads faster but add write cost, so they should match the XPath constraints actually used.

An anti-pattern where a microflow runs a retrieve or association lookup inside a loop, issuing one query per iteration. Replacing it with a single retrieve before the loop usually cuts database round trips dramatically.

A runtime configuration where a node keeps no user session state, so consecutive requests can be served by different nodes. Stateless is required for horizontal scaling; features relying on server-side session data stop working.

Running multiple runtime instances of the same app behind a load balancer, sharing one database and one file store. It increases throughput and availability but requires stateless operation and care with scheduled events and caching.

A runtime feature that executes microflows asynchronously in background threads, with configurable concurrency per queue. Useful for long-running or bulk work that should not block a user's request.

The main unit of modeling in a Mendix app, containing its own domain model, microflows, pages, security roles, and settings. Modules are versioned and can be exported for reuse in other apps.

A declared link from one module to another that allows use of the target module's public entities, microflows, and other documents. Circular dependencies are not allowed, so dependencies shape app architecture.

A named, typed value defined in a module that microflows and mappings can reference. Its value can be overridden per environment in the runtime settings, making it the standard place for external URLs and feature switches.

A deployed instance of the app with its own database, file storage, URL, and runtime settings, such as Development, Acceptance, and Production. Code and model are promoted between environments as deployment packages.

A configuration value set in the Mendix Portal or the model for a specific environment that overrides what is in the model, for example a constant, a database URL, or a log level.

A named category in the runtime logging configuration, such as Core or REST, with a threshold like Info, Warning, or Debug. Lowering the threshold on a node shows more detail in the environment's log files.

A model document that wraps a Java class so a microflow can call it, with declared parameters, a return type, and exception handling. The Java code uses the runtime API and is compiled into the deployment package.

The Java class Core in the Mendix runtime that provides static methods to instantiate, retrieve, commit, and delete objects, run XPath queries, and access the current context and session from Java code.

A microflow configured in the app settings to run automatically when a runtime instance starts, used to seed data, warm caches, or register handlers. A failure here can stop the app from starting.