Information Technology & Systems

SUMMARY: A database management system is a collection of interrelated data and a set of programs for accessing that data. Data is logically organized into characters, fields, records, files, and databases in an information system.

The five main components of a database system are data, hardware, software, procedure, and user. File organization is defined as the logical sequence in which the records are organized in the file.

File organization can be of the following types: pile, indexed, sequential, indexed-sequential, and hashed. Data models are mainly used for specifying the overall logical structure of a database and for providing a higher-level description of the implementation. Data models fall into three different categories, namely, record-based logical models, object-based logical models, and physical data models.

An ideal database system should ensure efficiency in storage and retrieval of data, data integrity, data independence, data consistency, along with data sharing and security.

In an organization, there are various categories of databases based on their use. They include operational databases, analytical databases, hypermedia databases, data warehouses, and distributed databases.

The process of database development is divided into the three phases, namely, database planning and modeling; database design; and database implementation and maintenance.

The Entity-Relationship model (E-R) is based on the perception of a real world that consists of entities and the inter-relationships between these entities.

Data dictionaries enforce standard data element definitions whenever end users and application programs use a DBMS to access an organization's databases. According to Bill Inmon, "A warehouse is a subject-oriented, integrated, time-variant and non-volatile collection of data in support of management's decision making process."

Data warehouse architecture represents the overall structure of data and has three components, namely, data source, data loaders and DBMS, and query and analysis tools. Data mining refers to extracting and analyzing the data from different sources and summarizing it into useful information.

The main objective of data mining is to look for (hidden) patterns in the data that can be used for formulating a business strategy or to look for unusual behavior.