Case-information systems technology

CASE-tool technology is a relatively new, formed at the turn of the 80-ies. direction. Widespread use of difficult extremely high costs and requirements to the hardware developer workplace.

CASE technology-the software complex, automates the entire technological process analysis, design, development and maintenance of complex software systems.

CASE tools technologies are divided into two groups:

§ embedded in system implementation-all solution for designing and implementing tied to the selected database management system (DBMS);

§ implementation of system-independent-all design decisions are focused on the harmonization of the initial stages of the life cycle and means of documenting, provide greater flexibility in the choice of means of implementation.

The main advantage of CASE-technologies-support project collaboration by allowing developers to work in a local network, export/import any fragments of the project, organizational project management.

Some CASE-technology focused only on designers and provide special graphical tools for images of various types of models:

§ data flow diagram (DFD-data flow diagrams) in conjunction with data dictionaries and process specifications;

§ chart “entity-relationship model” (ERD-entity relationship diagrams), is infologičeskoj a domain model (cm. ch. 15);

§ chart state transitions (STD-state transition diagrams), taking into account the events and the response to them data processing system.

DFD Diagram communicates sources of information with consumers, allocates logical functions (processes) conversion information, defines a group of data items and their storage (database).

Description of the structure of the data flows, their components are kept up to date in the data dictionary, that acts as a database project. Each logical function can detalizirovat′sâ using lower-level DFD in accordance with the methods of the downstream design (cm. ch. 18).

Run automated design specifications programs (set basic features for programming) and maintenance of the data dictionary.

Another class of CASE-technologies only supports development programs, including:

§ automatic generation of program codes based on their specifications;

§ check of correctness of descriptions of data models and data flow diagrams;

§ documentation of programs according to accepted standards and the current state of the project;



§ testing and debugging programs.

Code generation programs is performed in two ways: create a skeleton programs and creating full product. Skeleton program serves for subsequent manual editing of source texts option, providing the possibility of intervention of the programmer; full product not editable manually.

Under the CASE-technologies project is accompanied by a whole, and not just his program codes. Project materials, prepared in CASE technology, job serve programmers, and the programming rather comes down to coding is translated into a specific language data structures and methods of their processing, If no automatic code generation.

Most CASE-technologies also uses the method “prototypes” for quickly creating programs in the early stages of development. Code generation of programmes is carried out automatically-to 85 - 90% object codes and texts for the high-level languages, and as the languages most often used of hell, Si, COBOL.