Reserved Words
Complete reference for MDL reserved words and quoting rules.
Quoting Rules
Most MDL keywords now work unquoted as entity names, attribute names, parameter names, and module names. Common words like Caption, Check, Content, Format, Index, Label, Range, Select, Source, Status, Text, Title, Type, Value, Item, Version, Production, etc. are all valid without quoting.
Only structural MDL keywords require quoting: Create, Delete, Begin, End, Return, Entity, Module.
Quoted Identifiers
Quoted identifiers escape any reserved word using double-quotes (ANSI SQL style) or backticks (MySQL style):
DESCRIBE ENTITY "ComboBox"."CategoryTreeVE";
SHOW ENTITIES IN "ComboBox";
CREATE PERSISTENT ENTITY Module.VATRate ("Create": DateTime, Rate: Decimal);
Both double-quote and backtick styles are supported. You can mix quoted and unquoted parts: "ComboBox".CategoryTreeVE.
Words That Do NOT Require Quoting
The following common words can be used as identifiers without quoting:
| Category | Words |
|---|---|
| UI terms | Caption, Content, Label, Text, Title, Format, Style |
| Data terms | Index, Range, Select, Source, Status, Type, Value, Item, Version |
| Security terms | Production |
| Other | Check, and most domain-specific terms |
Words That Require Quoting
The following structural MDL keywords must be quoted when used as identifiers:
| Keyword | Example with quoting |
|---|---|
Create | "Create": DateTime |
Delete | "Delete": Boolean |
Begin | "Begin": DateTime |
End | "End": DateTime |
Return | "Return": String(200) |
Entity | "Entity": String(200) |
Module | "Module": String(200) |
Boolean Attribute Defaults
Boolean attributes auto-default to false when no DEFAULT is specified. Mendix Studio Pro requires Boolean attributes to have a default value.
CALCULATED Attributes
CALCULATED marks an attribute as calculated (not stored). Use CALCULATED BY Module.Microflow to specify the calculation microflow. Calculated attributes derive their value from a microflow at runtime.
ButtonStyle Values
ButtonStyle supports all values: Primary, Default, Success, Danger, Warning, Info.