Omnis Classic vs Omnis Studio

Technical Reference for Developers

This page outlines the major behavioural differences between Omnis Classic and Omnis Studio.
It focuses on practical areas where assumptions made in one environment will cause errors or unexpected behaviour in the other.

The intent is to provide a reliable reference when switching between Classic and Studio environments.

1. Execution Model

Procedural vs Object-Based

Omnis Classic executes code strictly in sequence.
There are no object methods, no event lifecycle, and no method dispatch system.

Omnis Studio introduces classes, instance variables, events ($construct, $destruct, $event()), and encapsulated logic.

Classic code is linear and deterministic. Studio code is event-driven and object-oriented.

2. Transaction Handling

Classic does not support:

• Begin transaction
• Commit
• Rollback

Everything is handled with procedural file commands.

Studio provides full transaction blocks and SQL-level rollback/commit support.

3. Code Formatting & Whitespace

Classic automatically:

• trims extra spaces
• normalises operator spacing
• rewrites indentation
• removes trailing spaces

Studio preserves developer formatting.

Classic code cannot rely on custom whitespace or unusual formatting to convey meaning.

4. Lists and Columns

4.1 Column Identification (Classic)

Classic identifies list columns by field name:

LL_List(FieldName, RowNum)

Studio often uses numeric index references unless otherwise defined.

4.2 Dynamic Access Using nam()

Classic uses:

Calculate LC_Col as nam(LC_ColName)

Studio typically uses object references instead.

5. The pick() Function

In Classic:

pick(valueList, match)

returns 0 when no match is found
(as long as no third parameter is supplied).

This behaviour is deliberate and widely used in Classic code.

Studio’s equivalent behaviours differ and may return null-like values.

6. Field, Variable, and Type Handling

Classic is permissive with types:

• characters convert loosely to numbers
• booleans behave as numeric values
• null-equivalents are simple blanks or zeros

Studio uses stronger type rules and clearer null states.

7. Window Behaviour

Classic windows are purely procedural:

• code executes directly
• data-entry affects timer behaviour
• few event hooks exist

Studio has a full event model:

• $construct
• $destruct
• evClick, evOpen, etc.
• internal object state

Classic UI logic must be written procedurally.

8. Timers

Classic timers:

• may stop firing during data entry
• must be controlled carefully
• rely on direct code execution

Studio timers follow object lifecycles and event dispatch.

9. Datafiles and SQL

Classic:

• depends on Omnis datafile technology
• uses procedural file commands
• typically relies on the Omnis Data Bridge for network access

Studio:

• supports SQL classes
• handles ODBC/JDBC connections
• provides schemas and data modelling tools

10. Summary

Omnis Classic is procedural, predictable, and minimalistic.
Omnis Studio is object-oriented, event-driven, and modern.

Understanding the differences avoids mistakes and preserves code integrity when switching between them.