4d-v21

Comprehensive 4D v21 development expert with embedded official documentation. Covers ORDA patterns, entity classes, data model classes, queries, classic methods, data types, error handling, forms, events, web server, and REST API. Use when working with 4D files (.4dm), 4D language questions, 4D project structure, entity classes, ORDA queries, database operations, form development, web server configuration, REST API usage, or any 4D-specific syntax issue. Includes full official 4D v21 documentation for on-demand retrieval. Triggers on: .4dm files, 4D code, ORDA, entity selection, dataclass, 4D query, 4D form, 4D web server, 4D REST, 4D command, 4D collection, 4D object.