Infor LN Session Programming Guide
Sessions are the fundamental building blocks of Infor LN's user interface and business logic layer. Each session represents a functional unit—a maintenance form, an inquiry screen, a processing program, or a report. Session programming in LN involves designing the data model, building the form layout, implementing business logic through BShell scripts, and connecting sessions through the menu and navigation framework. This guide provides the foundational knowledge LN developers need.
Session Architecture and Types
Infor LN sessions are classified by type: Type 1 (single-record maintenance), Type 2 (multi-record display/overview), Type 3 (print/report), Type 4 (processing), and Type 5 (special display). Each type has a predefined framework that handles standard operations—navigation, CRUD, printing, and processing—so developers focus on business-specific logic. Understanding which session type fits your requirement is the first design decision.
- Use Type 1 sessions for single-record data entry and maintenance with full CRUD operations
- Use Type 2 sessions for list views, overviews, and multi-record browsing with filtering capabilities
- Use Type 3 sessions for report generation with parameter forms and print device selection
- Use Type 4 sessions for background processing, batch operations, and data transformation jobs
Data Handling and Table Access
LN sessions interact with the database through table definitions that map to physical database tables. Session data handling follows a buffer model: data is read into session buffers, modified by the user or script logic, and written back to the database on save. Understanding the buffer lifecycle—when data is fetched, when it is validated, and when it is committed—prevents common programming errors like stale data reads and lost updates.
- Access data through LN table objects rather than raw SQL to maintain referential integrity and triggers
- Understand the buffer lifecycle: read populates buffers, validation checks buffer data, save commits to database
- Use table references for foreign key lookups rather than separate queries for related data
- Implement optimistic locking through the standard LN concurrency model to prevent lost updates in multi-user scenarios
Session Integration and Navigation
Sessions in LN connect through zoom, drill-down, and process-linking mechanisms. Zoom allows a session to open another session for data lookup and selection. Drill-down provides navigation from overview records to detail sessions. Process linking chains sessions together in a defined workflow. Designing clean session navigation improves user productivity and reduces training time by making the application flow intuitive.
- Implement zoom references on key fields to allow users to look up and select valid values efficiently
- Configure drill-down paths from overview sessions to detail sessions for natural data exploration
- Use process linking to guide users through multi-step workflows with automatic data passing between steps
- Register custom sessions in the LN menu structure with appropriate security permissions and help references
Building Infor LN sessions? Our development team trains and mentors LN session programmers.
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