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Meta Integration® Model Bridge (MIMB)
"Metadata Integration" Solution

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Description "Reference Guide"

  1. Technology Overview
    1. Metadata Movement Use Cases
    2. Metadata Movement Solutions
    3. Business Intelligence Metadata Engineering
  2. Known Limitations
  3. Frequently Asked Questions
    1. FAQ on Internationalization & Encodings
    2. FAQ on OMG XMI for UML and CWM
    3. FAQ on Microsoft Visio
    4. FAQ on Microsoft Repository

Known Limitations as of 2009/01/01

Table of Contents

  1. Consistency Check of the Source Model
  2. Metadata movement/conversion is limited to the "Mapping Specifications"
  3. Potential loss of metadata from Tool A to Tool B
  4. Limitations on Import/Export Round-Trip
  5. Limitations in the Receiving Environment for Merge/Update of Metadata
  6. API based Bridges
  7. Multi-file based Bridges
  8. Graphical Layout is carried only through some Bridges
  9. Transformation Expression based Bridges

Consistency Check of the Source Model

The user can select between "basic" or "detailed" consistency check of the imported model before the export to the target tool. This kind of model consistency check can detect disconnected relationships, foreign keys not connected to any primary or alternate key, etc. Having a centralized model validation between import and export allows to continuously improve the consistency check algorithms, and avoids each export bridge to retest for the same issues. Consistency checks can report "warnings" in the source model, or "errors" that are fatal and will prevent the export to any tool. The solution is to fix the original model, and then import it again. If the user purposly decides to turn off all consistency check (e.g. when the tool is not available to fix the source model), then the imported model may break the export bridge, or produce an invalid model that may break the target tool. MITI assumes no responsibility when consistency check is turned off.

Metadata movement/conversion is limited to the "Mapping Specifications"

The metadata mapping and transformations implemented by Meta Integration® Model Bridge (MIMB) are limited to the published model mapping specifications for each integrated tool. Such specifications are part of the MIMB online help, and are also published on the web http://www.metaintegration.net/Products/MIMB/Documentation/

Potential loss of metadata from Tool A to Tool B

There are 7 points of potential metadata loss from Tool A to Tool B:

  1. Tool A's Methodology/Metamodel Support & Implementation,
  2. Tool A's Export Capabilities,
  3. MIMB's Import Bridge for Tool A,
  4. MIR's Methodology/Metamodel Support & Implementation,
  5. MIMB's Export Bridge for Tool B,
  6. Tool B's Import Capabilities,
  7. Tool B's Methodology/Metamodel Support & Implementation.

MITI provides the best possible metadata mapping across methodologies and tools. However, some modeling concepts may not be available in Tool A, MIR, or Tool B. In such a case, the import & export bridges try to use the descriptions or notes to carry such modeling concepts all the way from the source to the target tool without any loss.

Limitations on Import/Export Round-Trip

There are an additional considerations when performing what is often referred to as a "round-trip", or importing from tool A, exporting to tool B, editing the model (or not) in tool B, re-import this model in from tool B, and exporting back to tool A. In this case, the 7 points of potential metadata loss identified above are compounded so that there are now 7 additional points of loss:

The fidelity of some simple types of metadata may be well maintained, where there is a direct, one-to-one, translation from tool A --> MIR's methodology --> tool B and then back again. Examples include tools with the same methodology and metadata coverage (e.g., a data modeling and design tool to another data modeling or design tool), or simple elements like the name, description, layout, etc. This process is referred to as "round-tip migration", and may work successfully given these restrictions.

However, it is never recommended that a combination of import-> export-> edit-> export-> import (i.e., "round-trip engineering") be expected to retain fidelity when there is a migration from tool A to tool B (and vice-versa) of methodology, metadata coverage or any of the known limitations identified above. What round-trip engineering implies is a forward-engineering and then reverse engineering process, which has never been a reality in systems engineering. One should not expect the forward engineering of simple to complex transformations (e.g., forward engineering from a spreadsheet to an ETL tool and then reverse engineering from the ETL tool back to a spreadsheet) would be reversible, or even bear much resemblance to the original.

The proper process is to treat the forward-engineering step as "irreversible", treat the reverse engineering step as a separate process, and not expect to effectively compare the original will the "round-trip" result, nor re-use the result for further engineering of the metadata.

Some examples:

Limitations in the Receiving Environment for Merge/Update of Metadata

The export bridges generally depend upon the tool receiving the metadata to integrate the metadata correctly, i.e., provide compare, merge and integrate capabilities. Such capabilities are:

In order to accomodate these limitations in the destination tool, the following MIMB export bridges offer "limited" metadata update capabilities (Please see the bridge parameter tooltips for more details):

API based Bridges

Some MIMB bridges rely on the tool's API to import/export metadata, for example:

Such MIMB bridges require these tools to be installed with their API properly setup on the machine (PC) where the MIMB bridge is executed.

Multi-file based Bridges

When multiple files are involved, all them them must be accessible to the MIMB bridge.

Some MIMB bridges have paramaters of type "Directory" instead of just "File", and therefore require access to a directory of multiple files, for example:

Some MIMB bridges have parameters of type "File" which support the notion of "include" files, and therefore require access to all the specified include file paths, for example:

Graphical Layout is carried only through some Bridges

Some MIMB bridges convert the graphical information between tools, including conversion of the model layout between various notations like IDEF1X data modeling, and UML object modeling. The following MIMB bridges carry graphical information:

However, some MIMB bridges do not transfer the graphical information of the model layout. The primary reason for this limitation is that the import / export capabilities of most tools do not provide graphical information. In other words, their published file formats and/or Application Programming Interface (API) cover the semantic (each of the modeling concepts), but not the graphical information (i.e. the concept's associated shape sizes and positions). Furthermore, when available, such graphical information is not easily reusable in the target tool. This problem is also true for tools sharing the same methodology (e.g. a tool may allow a graphical layout that is not graphically implementable in another equivalent tool). This problem is accentuated when crossing methodology boundaries (e.g. IDEF1X to UML).

Transformation Expression based Bridges

Parsing of Transformation Expressions in Import Bridges

Some MIMB Import Bridges depend on "Transformation Expression Parsing" to capture the transformation semantic (i.e. ClassifierMap and FeatureMap). Such parsing might be limited by the complexity of the transformation expression (e.g. proprietary SQL language extensions). MIMB bridges depending on "Transformation Expression Parsing" include the following import bridges:

Conversions of Transformation Expressions in Export Bridges

Some MIMB Export Bridges depend on "Transformation Expression Conversions" to restore the transformation semantic (ClassifierMap and FeatureMap). Such conversion might be limited by the complexity of the transformation expression. MIMB bridges depending on "Transformation Expression Conversions" include the following export bridges:

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