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1.1 Important

Because changes made to the method definitions also implicitly change the models based on the methods, changing components of a method that is in use can have far-reaching and possibly undesired effects. We have done our best to ensure that no change is possible which would damage old models. However, there are changes that might be desirable in one situation and positively detrimental in another. You should be especially wary of making changes to the predefined methods that were delivered with the MetaEdit+ Method Workbench package, because then you might not be able to use our new versions of the methods. If you want to modify the predefined methods, you could subclass the appropriate components and modify the subclasses.

Because method development also affects existing system descriptions, changing the underlying metamodel on the fly, the method development tools provide very powerful functions for CASE customisation. Therefore you should be aware that:
Modifications to types affect all the models that have been made, or will be made with all the techniques, where the type is used.
The modifications will affect model data on the next access to it. In a multi-user situation, changes to types, like changes to instances, only affect other users after you have committed and they have started a new transaction.

So before any big modification efforts, remember to backup your database! This is particularly important in changes involving adding, moving or removing properties from a type, or changing the data type of a property type.

If you are unable to make modifications to methods, check that you are running the Method Workbench version of MetaEdit+, and that your system administrator has included you in the set of users allowed to metamodel. If you are running the multi-user version of MetaEdit+, your system administrator may also have set restrictions about simultaneous metamodellers and modellers, e.g. metamodelling is only allowed when nobody else is logged in (the default), or only one metamodeller (and any number of modellers) is allowed at a time.

Before trying out any of these tools, read these chapters carefully!

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