Model Comparator

What are filters?

Before comparing two models you will need to specify the fields or objects that you wish to compare, these are called filters. You may then decide to save a filter to reuse it later on.

You can combine the different types of filters:

• methodology (UML, IDEF1X, not restricted)
• design level (logical, physical, not restricted)
• compare the architecture (Packages/Diagrams)
• compare the documentation properties (description and note properties)
• what is the identification field (Physical ID, Logical Name, Physical Name)

Click on the button to start the selection of the models and the filter creation process.

Fig. 1. Starting the comparator

Then select the matching policy (figure 2) and the fields that will be compared or not compared as the primary cause of similitude. For example, in general you will say the primary cause of similitude is the name of the object. The name is the identifier for a logical comparison. For the physical comparison it is the physical name (or the logical name if no physical name is present) or the physicalID if you use the physicalID to uniquely identify your objects. If you do not choose to use an identity, it will look beyond the name. This is useful in the case where a tool may call an attribute IDEF1X_attribute and another tool UML_attribute but the rest of the attributes of the objects are the same.
Also, for the objects that have a type (Attribute, Argument...), all the properties of type are used to determine if the objects are comparable. You can specify that only the datatype specific properties (datatype, length, precision) be used when comparing theses objects. To do so, select the "Migrate the Type properties" check box.

Fig. 2. Matching policy

You may then specify how you would like the comparison to proceed (figure 3). Whether you would like to restrict it by comparing only the physical part of the model or the logical part of the model or if you don't want to restrict the comparison.

Fig. 3. Design level

You may then specify the type of view to use to restrict the comparison (figure 4), i.e., you may say to compare the models as if they were both IDEF1X or to compare them as if they were both UML, or to ignore the view.

For example, if you want to compare a model from an IDEF1X tool and a model from a UML tool you will choose the IDEF1X methodology in order to avoid comparing operations.

Fig. 4. Type of view

In most cases you will not want to compare the descriptions and the notes that have been used to describe each object. However, there are cases where you may wish to do so in which case you should check the documentation check box.

In some cases, for example when comparing models that come from tools with a different policy for organizing the contents of a model, you may want to ignore the diagrams and packages, and to concentrate only on 'significant' objects (classes, attributes, associations). To do so, uncheck the "Compare the model structure" check box.

If you use the comparator as a first step for data migration, you want to concentrate only on the classes and attributes. You may ignore the relationships (associations, generalizations, realizations...). To do so, uncheck the "Compare the relationships" check box.

Fig. 5. Description and notes

In some cases you may wish to specify how to handle character strings (figure 6). This window allows you to choose how you want to handle the case and the blank charaters in names.

Theses filters will be used to determine if two objects are comparable. You can also apply these rules to the result of the comparison. In this case, in the result attribute panel, the name property of two objects can be said EQUAL even if they are not strictly equal but differs only in one of the previous way.

Fig. 6. What about strings?

The following panel (figure 7) allows you to tune on the comparison.

You can choose not to compare the position property (for the objects for which this property is set). However, if the position is an identifying property (like the position property of an argument), it is always compared.

You can ignore the name of the associative objects (keys, association roles, ...) during the comparison. This is useful when the design tool automatically assign a name for these objects.
In any case, the name is not an identifying property for these objects (two objects with a different names may be found comparable). But if the name is compared, if two objects have the same name, they will be compared, whether they really are comparable or not.

Fig. 7. Advanced options

After having dutifully filled out the precedent screens you may store the information in a file for reuse. Or you can start the comparison by clicking on the "Compare" button.

Fig. 8. Starting the comparison

To store the filter click on the save button in the last pane of the wizard. A new window is dispalyed.
Select "New Filter" in the filters box and specify the name of the new filter in the text field below.
To overwrite an existing filter, select it in the filters box.
Click on "Save". The filters are saved in a special file that is internal to the system.

Fig. 9. Saving the filter