Upgrading an Information Model

This topic provides information about using different versions of information models and Extensible Markup Language (XML) interchange formats. Generally, you can omit upgrading (that is, replacing) an existing information model with a newer format of the same information model if you do not require the additional meta data types that the newer format provides.

If you do choose to replace an older information model format with a newer format, you must copy your object instance data to the new information model. XML interchange provides the means to move your data.

Open Information Model Formats

The Open Information Model (OIM) is a generic information model. OIM 1.0 and the Meta Data Coalition (MDC) OIM are two alternate modeling formats of the OIM. MDC OIM is an enhanced version of OIM 1.0 that includes Unified Modeling Language (UML) 1.3 support. OIM 1.0 and the MDC OIM use the same repository tables and cannot be installed into the same repository database. If you want to use the MDC OIM, you must copy your OIM 1.0 meta data to the new information model.

• OIM 1.0 is supported by repository engine 2.0 and repository engine 3.0. A version of OIM 1.0 is distributed with Microsoft® SQL Server™.
  
  
• MDC OIM is supported by repository engine 3.0, and it is the newer of the two formats. A version of MDC OIM is distributed with the SQL Server 2000 Meta Data Services Software Development Kit (SDK).

You can exchange and migrate meta data between these two model formats using either XML interchange format. The following section discusses backward compatibility in more detail. For more information about XML Interchange Format (XIF) and backward compatibility, see Using XML Encoding.

XML Interchange Formats

XML interchange formats define the way in which you can exchange meta data in XML with other tools and repositories. You can choose between two alternate XML interchange formats.

• XIF is supported by repository engine 2.0 and repository engine 3.0. It expresses meta data in entity-normal format.
  
  
• MDC XML Encoding is supported by repository engine 3.0, and it is the native format of the MDC OIM. It expresses meta data in attribute-normal format. MDC XML Encoding conforms to the XML specification published by the World Wide Web Consortium (W3C).

XIF and MDC XML Encoding are two alternate encoding mechanisms. They are not compatible.

Note  In practice, because MDC OIM and MDC XML Encoding are not supported by repository engine 2.0, you cannot pair OIM 1.0 with MDC XML Encoding unless you are running repository engine 3.0. MDC OIM and XIF are not compatible. You cannot pair MDC OIM with XIF under any circumstances.

The following table lists which versions of the OIM and XML interchange format you can use with each repository engine version.

Engine version	OIM version	XML version
2.0	OIM 1.0	XIF
3.0	OIM 1.0 MDC OIM	XIF or MDC XML Encoding MDC XML Encoding only

Meta Data Interchange Combinations

The following table recommends an XML interchange format for each information model source-target combination, for all versions of the repository engine.

Engine version	Source model version	Target model version	Recommended XML interchange
2.0	OIM 1.0	OIM 1.0	XIF
3.0	OIM 1.0	OIM 1.0	MDC XML Encoding
3.0	OIM 1.0	MDC OIM	MDC XML Encoding
3.0	MDC OIM	MDC OIM	MDC XML Encoding
3.0	MDC OIM	OIM 1.0	MDC XML Encoding

See Also

Information Models

OIM in Meta Data Services

Retaining Legacy Components in a Repository

Upgrading from Earlier Versions

Upgrading the Repository Engine

XML in Meta Data Services