Simplifed LOM Schema
by Claude Ostyn
© 2006 Claude Ostyn

Overview

This document describes a simplified LOM XML schema that conforms to the IEEE standard. Using this schema instead of the multiple files and folders of the reference IEEE schema can greatly simplify packaging and editing of metadata in SCORM 2004 packages. This can be accomplished without affecting conformance.

Problem statement

SCORM 2004 specifies that metadata, when included in a package manifest, should conform to the IEEE LOM (Learning Object Metadata) standards for both the LOM data model and the XML schema. However, the sample schema provided with the LOM XML standard is extremely cumbersome. The sample schema is actually a collection of schema fragments that can be recombined in various ways depending on the required level of conformance. As a result, the sample schema consists of 18 files distributed over five folders. Since it is quite difficult even for an XML expert to determine which of these files and folders must be included in a SCORM package, the safe approach has been to include them all. This means including all the files and folders. For example, you have to include a folder named "common" just to hold some of the common sub-schemas.

Another problem is that some popular free XML tools don't work well with such multilayered schemas with nested imports. This makes the editing of simple metadata records much more difficult than it should be.

Many of the problems described above can be solved by consolidating the 18 files and four subfolders of the schema into a single file.

Description

This schema is a single file consolidation of the sample schema published with IEEE Std 1484.12.3-2005 - IEEE Standard for Learning Technology- Extensible Markup Language (XML) Schema Definition Language Binding for Learning Object Metadata

Unlike the sample schemas that accompany the IEEE standard, which uses multiple subdirectories and cross-referencing namespaces, this schema is a single file in order to simplify its inclusion and reference in content packages, e.g. SCORM packages, and in other applications.

This schema was constructed as follows:

1. Select the "Custom" profiles of the original IEEE sample schema to allow extension elements and attributes
2. Use the strict schema for name uniqueness
3. Allow use of alternative, unrestricted vocabularies or the LOM v1.0 vocabularies.
4. Consolidate all the relevant declarations into a single file and namespace
5. Rename declarations such as type names, group names, etc. where they conflict when they are brought into a single schema. The elements that would be found in an XML instance conforming to this or the original LOM schema are of course not renamed.

Except as described above, declarations and datatypes are not modified.

Because this schema defines a profile, not every IEEE conformant instance is guaranteed to validate with this schema, but strictly conformant instances and instances that use custom extensions but that do not rely on the loose schema definition should validate. A strictly conformant instance is one that does not contain any extension.

Conformance

IEEE conformance

This schema is a conforming implementation of IEEE Std 1484.12.3-2005 - IEEE Standard for Learning Technology- Extensible Markup Language (XML) Schema Definition Language Binding for Learning Object Metadata

SCORM conformance

Packages using this schema for the metadata pass the ADL Conformance Test Suite for SCORM 2004 3rd Edition.

Known issues and limitations

This schema implements just one of the profiles supported by the IEEE sample schema. This is the "custom" profile, which provides strict datatype validation but also allows custom extensions. Custom extensions require the appropriate namespace declaration and reference to a schema location.

The label for the namespace defined in this schema is the same as the label for the namespace defined in the IEEE sample schema, and the namespace structure and data types are exactly the same. This should allow easy processing of the XML instances by systems that assume the IEEE sample schema. However, if a system checks for a reference to a specific schema file that exists in the IEEE sample schema, or has some other dependency on the nesting and imports of the sample schema, it may fail to validate or process the XML instances. If this should occur, it is trivial to translate the XML instance into a new instance with the expected specific schema dependencies, using XLST or an equivalent process.

Download

Please read the no nonsense License and terms of use below before downloading or using this tool.

Right-click here to download a zip file containing the schema (.xsd file).

License and terms of use

This work is licensed under a Creative Commons Attribution-ShareAlike2.5 License.
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