Write about data definition language commands (DDL) The data definition language commands are used to create objects (tables). Alter the table structure of an object, and also to drop the object, the DDL contains the following commands. Create Alter Drop Truncate 1. CREATE: The create command is used to create database objects such as table, […]
Category: Materials
Generation of computers
The computer generation means step-by-step growth in the technology. It is often used in relation to the hardware of computer. There are totally five generations of computers till today. The following table illustrates the generations of computer hardware: First Generation (1940-1956) Second Generation (1956-1965) Third Generation (1966-1975) Fourth Generation (1976-1990) Fifth Generation (1990-Present First Generation […]
How to create user name in SQL
How to create user name in SQL? What is the right way to use sql commnds Step1: First you need to connect system user. If you want to connect system user use the following command. Sql> conn system/oracle; Step2: After connecting the system user you need to create your own user account. Sql> create user […]
Computer Applications
Computer Applications Computers are seen everywhere around us, in all spheres of life.Computers have now become an essential part of our lives.Today, computers are widely used in fields such as engineering, health care, banking, education and research, travel and tourism, weather forecasting,social networking, E commerce and so on. Government: Computers are used in government Organizations […]
CSS Selectors with examples
CSS Selectors Selector is a syntax to select the element.First we have to select the element and then we have to apply style. Tag selector Id selector Class selector Compound selector Grouping selector Child selector Direct child selector Attribute selector Tag Selector: It selects all instances (examples) of a specific tag. Syntax: tag Id selector: […]



