A primary key is a field in a table which uniquely identifies each row/record in a database table. Primary keys must contain unique values.

The system catalogs are the place where a relational database management system stores schema metadata, such as information about tables and columns and internal book keeping information.

A peer-to-peer (P2P) network is created when two or more PCs are connected and share resources without going through a separateserver computer.

The Hypertext Transfer Protocol (HTTP) is an application protocolfor distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web.

Bluetooth is a wireless technology standard for exchanging data over short distances from fixed and mobile devices and building personal area networks (PANs).Invented by telecom vendor Ericsson in 1994.

The Open Systems Interconnection model is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard of their underlying internal structure and technology.

A network switch is a computer networking device that connects devices together on a computer network, by using packet switching to receive, process and forward data to the destination device.

Star topology arrangement, every node connects to a central hub, switch or computer. The hub acting as a server and the peripheral devices as clients.

A worksheet is a collection of cells where you keep and manipulate the data. By default, each Excel workbook contains three worksheets.