«Data modeling concepts in software engineering ppt» in pictures.
- System models
- Object oriented software engineering
- From Task Analysis and Task Modelling to Task Model Engineering
85 Object behaviour modelling
A behavioural model shows the interactions between objects to produce some particular system behaviour that is specified as a use-case. Sequence diagrams (or collaboration diagrams) in the UML are used to model interaction between objects.
Object oriented software engineering
78 Data dictionaries Data dictionaries are lists of all of the names used in the system models. Descriptions of the entities, relationships and attributes are also included. Advantages Support name management and avoid duplication Store of organisational knowledge linking analysis, design and implementation Many CASE workbenches support data dictionaries.
From Task Analysis and Task Modelling to Task Model Engineering
This model defines a database as a collection of objects, or reusable software elements, with associated features and methods. There are several kinds of object-oriented databases:
86 Multiple inheritance Rather than inheriting the attributes and services from a single parent class, a system which supports multiple inheritance allows object classes to inherit from several super-classes. This can lead to semantic conflicts where attributes / services with the same name in different super-classes have different semantics. Multiple inheritance makes class hierarchy reorganisation more complex.
Conceptual, logical and physical model or ERD are three different ways of modeling data in a domain. While they all contain entities and relationships, they differ in the purposes they are created for and audiences they are meant to target. A general understanding to the three models is that, business analyst uses conceptual and logical model for modeling the data required and produced by system from a business angle, while database designer refines the early design to produce the physical model for presenting physical database structure ready for database construction.
68 Data flow diagrams DFDs model the system from a functional perspective. Tracking and documenting how the data associated with a process is helpful to develop an overall understanding of the system. Data flow diagrams may also be used in showing the data exchange between a system and other systems in its environment.
9 System modelling System modelling helps the analyst to understand the functionality of the system and models are used to communicate with customers. Different models present the system from different perspectives External perspective showing the system’s context or environment Behavioural perspective showing the behaviour of the system Structural perspective showing the system or data architecture
Filed Under: Testing throughout the testing life cycle Tagged With: advantages of RAD model, Application generation, Business modeling, Data modeling, Diagram of RAD-Model, disadvantages, Disadvantages of RAD model, phases in RAD model, Process modeling, RAD model, Rapid Application development model, Testing and turnover, The phases in the rapid application development (RAD) model, when to use RAD model
In this model, the structural data usually contained in the database schema is embedded with the data itself. Here the distinction between data and schema is vague at best. This model is useful for describing systems, such as certain Web-based data sources, which we treat as databases but cannot constrain with a schema. It’s also useful for describing interactions between databases that don’t adhere to the same schema.
8 Topics covered Context models Behavioural models Data models
Object models CASE workbenches