Chapter 9, Problem 2 : 2. Refer to the list of features and...

2.Database management system. The heart of a 4GL, used for storing formatted data records, unformatted text, graphics, voice, video.

Data dictionary. Stores the definitions of the vari­ous kinds of data.

Nonprocedural language. Commands can occur in any order, rather than the sequence required by the computer.

Interactive query facilities. Permit the retrieval of ad hoc information using dialogues and menus.

Report generator. A flexible query facility used directly by end users to retrieve information and generate reports in diverse formats.

Selection and sorting. The ability to extract desired information from records and to sort the information as desired.

Screen formatter. A facility to easily develop screens interactively.

Word processor or text editor. Ideally a comprehensive word processor with a full screen editor for creating and changing text. Mail list and merge capabilities are also desirable.

Graphics. Standard routines for creating bar charts, histograms, connected point plots, scatter diagrams, and other graphics capabilities.

Data analysis and modeling tools. Some 4GLs include statistical packages for calculating time series, averages, standard deviations, and correlation coefficients, others are specifically dedicated to data analysis and reporting.

Library of macros. A facility for storing and recalling sequences of commands for repeatability in the future.

Programming interface. Linkages to procedural languages such as BASIC, COBOL, ALGOL, PL/1, or C for permitting programmers to handle more complex and conditional logic than might normally be found in the 4GL.

Reusable code. A facility for storing and retrieving prewritten program modules for insertion into other programs at will to improve productivity. Avoids a need to “reinvent the wheel” for standard or common functions.

Reusable software components and repositories.

Software development library. Tools to support more rapid system development.

Backup and recovery. A facility for automatic storage backup as well as procedures for restart and recovery.

Security and privacy safeguards. Features like password protection, data encryption, and data access controls.

Links to other DBMS. Optional interfaces to other popular DBMS such as IMS, and DB2 to enable transparent data transfer between these systems.