2.1 Graph Tool

2.1.1 Defining new graph types
2.1.2 Modifying existing graph types
2.1.3 Graph Tool command reference
2.1.4 Basics
2.1.5 Types tab
2.1.6 Bindings tab
2.1.7 Subgraphs tab
2.1.8 Constraints tab

2.1 Graph Tool

The Graph Tool provides the functionality to access, view and modify modeling language specifications at the graph level (e.g. specifications of the Family Tree diagram technique and its elements).

Graph Tool

Figure 2–1. Graph Tool.

The Graph Tool provides a tabbed five-page user interface for defining graph types. The pages and their responsibilities are as follows:

	Basics for entering the elementary information (e.g. name, properties and documentation) about the graph type itself.
	Types for defining the non-property types that the respective graph type may include.
	Bindings for defining the legal binding construct within the respective graph type.
	Subgraphs for defining the decomposition and explosion links for the graph type.
	Constraints for defining various additional rules enforced by the graph type.

The Graph Tool supports the creation of a modeling language in a top-down approach, or its assembly in a bottom-up approach.

In most cases it is recommended to follow the top-down approach, creating an empty Graph type first and then incrementally creating and adding language components step by step. The Graph Tool enables this wizard-like feature by providing commands to add new language components, opening the appropriate tool to create and edit them, and adding them into the Graph type.

In a bottom-up approach you first create language elements like object, relationship and role types and then combine these into a language with the Graph Tool. This approach is recommended when you are building a language by reusing existing language constructs (for example, constructing a UML Class Diagram using pieces from some other object-oriented modeling language).

It is worth noting that the other non-property metamodeling tools (Object, Relationship, Role and Port tools) share the features and functionality provided by the Graph Tool’s Basic page (e.g. creating a new type with associated properties). Hence the tool reference and instructions in Chapter 2.1.4 Basics are applicable for these tools as well.