10.1 Overview Any large system must be divided into several small units such that people can only handle limited information at a time, and the working groups that are handled separately from each other will not interfere with each other. Model management consists of dependencies between packets and packets. 10.2 Package is part of the model, and each part of the model must belong to a package. Models can assign the contents of the model into the package. However, in order to make it work, allocation must follow some reasonable principles, such as public rules, closely coupled implementation and public views. UML does not force what rules on how to set packages, but a good solution will greatly enhance the maintenanceability of the model. The package contains the top layer, that is, any element that is not included in other elements, such as the relationship between the classes, and them, state machines, examples of example, interaction, and collaboration. Some elements are included, such as attributes, operation, status, lifelines, and messages, are included by other elements, not directly in the package. Each top element has a package, which is declared in this package that is called the "home" package of the element. It may be referenced by other packets, but its ownership belongs to a home package. In a good configuration control system, the modelers must be able to access the package to modify the content of the element, which provides an access control mechanism for the processing large model. The package is also a unit of any version publishing mechanism. A package can contain other packages, and the root pack can indirectly contain the entire model of the system. There are several possible ways in the organization, and other basic principles selected by views, functions, or modeling can be used. The package is a general hierarchy unit in the UML model. They can be used to store, access control, configuration management, and construct reusable model parts libraries. If the plan is reasonable, they can reflect the high-level architecture of the system - the system is combined with the dependency between the subsystem and the dependencies thereof. The dependence between the bags outline the dependencies between the contents of the package. 10.3 Relational relationship dependencies between the package appears between independent elements, but in any size system, they should be observed from higher levels. The dependence between the bags outlines the dependencies of the elements in the package, that is, the dependency between the package can be exported from the dependency between the independent elements. The presence of inter-package dependencies indicates that there is a bottom-up method (a presentation declaration), or allows for an overhead method (restricting any other relationship constraint), there is at least one independent element in the corresponding package. The relationship between a given type of dependencies. This is a "existential statement" and does not mean that all elements in the package have dependencies. This indicates a logo with further information, but the cladding dependency does not contain any deeper information, it is just a summary. The top-down method reflects the entire structure of the system, and the upward method can be automatically generated from the independent element. Two methods in modeling have their own position, even in a single system. A plurality of dependencies between the independent elements belong to the same category are aggregated into a separate cladding dependency between the package, and the independent elements are included in these packets. If the dependency between the independent elements contains a structure type (such as several different uses), in order to generate a single high-level dependency, the structure in the cladding dependency may be ignored. The package is indicated by a rectangle with a label, and the dependency is represented by a dashed arrow. Figure 10-1 shows the package structure diagram of the booking system. External bag outside. There is a dependency between the two changes of the Seat Selection, and any of the implementations and any of the sub-systems will only include one of them.
