DESCRIBE STRUCTURE

The DESCRIBE STRUCTURE command gives you a compact, tree-style overview of a project. It is the fastest way to understand the overall shape of an application – what modules exist, what types of documents they contain, and how large each module is.

Default view

With no arguments, DESCRIBE STRUCTURE displays all user modules at depth 2 – modules with their documents listed by type:

DESCRIBE STRUCTURE;

Example output:

MyFirstModule
  Entities
    Customer (Name, Email, Phone, DateOfBirth, IsActive)
    Order (OrderNumber, OrderDate, TotalAmount, Status)
    OrderLine (Quantity, UnitPrice, LineTotal)
  Microflows
    ACT_Customer_Save ($Customer: Customer) : Boolean
    ACT_Order_Process ($Order: Order) : Boolean
    DS_Customer_GetAll () : List of Customer
  Pages
    Customer_Overview
    Customer_Edit ($Customer: Customer)
    Order_Detail ($Order: Order)
  Enumerations
    OrderStatus (Draft, Submitted, Approved, Rejected, Completed)
Administration
  Entities
    Account (FullName, Email, IsLocalUser, BlockedSince)
  Microflows
    ChangeMyPassword ($OldPassword, $NewPassword) : Boolean
  Pages
    Account_Overview
    Login

This gives you a bird’s-eye view without opening individual elements. Entity signatures show attribute names; microflow signatures show parameters and return types.

Depth levels

The DEPTH option controls how much detail is shown:

DEPTH 1 – Module summary

Shows one line per module with element counts:

DESCRIBE STRUCTURE DEPTH 1;

MyFirstModule       3 entities, 3 microflows, 3 pages, 1 enumeration, 2 associations
Administration      1 entity, 1 microflow, 2 pages

This is useful for getting a quick sense of project size and where the complexity lives.

DEPTH 2 – Elements with signatures (default)

This is the default when you run DESCRIBE STRUCTURE with no depth specified. It shows modules, their documents grouped by type, and compact signatures for each element. See the example under Default view above.

DEPTH 3 – Full detail

Shows typed attributes and named parameters:

DESCRIBE STRUCTURE DEPTH 3;

MyFirstModule
  Entities
    Customer
      Name: String(200)
      Email: String(200)
      Phone: String(50)
      DateOfBirth: DateTime
      IsActive: Boolean DEFAULT false
    Order
      OrderNumber: AutoNumber
      OrderDate: DateTime
      TotalAmount: Decimal
      Status: MyFirstModule.OrderStatus
    OrderLine
      Quantity: Integer
      UnitPrice: Decimal
      LineTotal: Decimal
  Microflows
    ACT_Customer_Save ($Customer: MyFirstModule.Customer) : Boolean
    ACT_Order_Process ($Order: MyFirstModule.Order) : Boolean
    DS_Customer_GetAll () : List of MyFirstModule.Customer
  Pages
    Customer_Overview
    Customer_Edit ($Customer: MyFirstModule.Customer)
    Order_Detail ($Order: MyFirstModule.Order)
  Enumerations
    OrderStatus
      Draft 'Draft'
      Submitted 'Submitted'
      Approved 'Approved'
      Rejected 'Rejected'
      Completed 'Completed'
  Associations
    Order_Customer: Order -> Customer (Reference)
    OrderLine_Order: OrderLine -> Order (Reference)

Depth 3 is verbose but gives you the most complete picture without running individual DESCRIBE commands.

At depths 2 and 3 each page also lists its outermost data widgets, the ones that set up a data context, for example Page MyFirstModule.Customer_Edit [DataView<Customer>]. A data widget nested inside another one is not listed. The widget index is built only by REFRESH CATALOG FULL, so on a default catalog pages print without the list.

Filtering by module

Use IN to show only a single module:

DESCRIBE STRUCTURE IN MyFirstModule;

This produces the same tree format but limited to one module. Combine with DEPTH for control over detail:

DESCRIBE STRUCTURE DEPTH 3 IN MyFirstModule;

Including system modules

By default, system and marketplace modules are hidden. Add ALL to include them:

DESCRIBE STRUCTURE DEPTH 1 ALL;

MyFirstModule       3 entities, 3 microflows, 3 pages, 1 enumeration, 2 associations
Administration      1 entity, 1 microflow, 2 pages
Atlas_Core          0 entities, 0 microflows, 12 pages
System              15 entities, 0 microflows, 0 pages

This is useful when you need to see system entities (like System.Image or System.FileDocument) or check what a marketplace module provides.

Using DESCRIBE STRUCTURE from the command line

# Quick project overview
mxcli -p app.mpr -c "DESCRIBE STRUCTURE DEPTH 1"

# Detailed view of one module
mxcli -p app.mpr -c "DESCRIBE STRUCTURE DEPTH 3 IN Sales"

# Full project including system modules
mxcli -p app.mpr -c "DESCRIBE STRUCTURE ALL"

When to use DESCRIBE STRUCTURE vs SHOW + DESCRIBE

DESCRIBE STRUCTURE is best for orientation – understanding the shape of the project at a glance. For detailed work on specific elements, switch to DESCRIBE.

What is next

Now that you can explore a project, you are ready to start making changes. Continue to Your First Changes to learn how to create entities, microflows, and pages using MDL.