Database System Lecture 02 Types of Databases Singleuser

Database System Lecture 02

Types of Databases • Single-user: • Supports only one user at a time. If user A is using the database user B or C must wait until user A is through • Desktop: • Single-user database running on a personal computer • Multi-user: • Supports multiple users at the same time

Types of Databases (continued) • Workgroup: • Supports a small number of users(usually fewer than 50) or a specific department within an organization • Enterprise: • Used by an entire organization (usually 100 s of users) across many departments

Types of Databases (continued) Can be classified by location: • Centralized: • Supports data located at a single site • Distributed: • Supports data distributed across several sites

The Database System Environment • Database system is composed of five main parts: • Hardware • Software • Operating system software • DBMS software • Application programs • People • Procedures • Data

The Database System Environment (continued)

Components of DBMS Environment • Hardware • PC, workstation, mainframe, a network of computers. • Software • DBMS, operating system, network software (if necessary) and also the application programs. • Data • Used by the organization and a description of this data called the schema. • Procedures • Instructions and rules that should be applied to the design and use of the database and DBMS. • People

What is Database Administrator (DBA)? • Database administrators (DBAs) use specialized software to store and organize data. • The role may include capacity planning, installation, configuration, database design, performance monitoring, security, troubleshooting, as well as backup and data recovery.

Data Dictionary • In database management systems, a file that defines the basic organization of a database. • A data dictionary contains a list of all files in the database, the number of records in each file, and the names and types of each field. • Data dictionaries do not contain any actual data from the database, only bookkeeping information for managing it. Without a data dictionary, however, a database management system cannot access data from the database.

Manual System • A manual system is a bookkeeping system where records are maintained by hand, without using a computer system. • A manual database is a hard-file storage system that consists of paper records and folders.