Compiled by Deepa Bhatia
What is DATABASE?
Definition of DATABASE
A Database is the collection of data organized and structured in a logical way.
Meaning
A database is just the container that helps to store, organize, manipulate and retrieve the data in the more organized way. It is like the empty container which does not provide any functionality expect providing the virtual space to store the data in the form of tables. All the tables in one database should be connected to each other in some or the other way. Database allows data to be stored and manipulate quickly as well as easily.
Databases we use in day to day life
· Telephone Directory
· Grocery List
· Address or Contact List
· Bank Pass Book & Statements
· Dictionary
· Salary & Wages Information
Advantages of Databases
· Improved data security
· Data is easily manageable as compared to traditional way of storage Eg: Paper storage in files and folders takes lots of storage which can be saved if digital database is used.
· Physical storage problems have been solved dramatically because of such an invention.
· Many users can view the data across various locations as it is stored digitally without the hassle of taking the paper storage from storage location to the required location.
· Reduced data redundancy
· Reduced updating errors and increased consistency
· Greater data integrity and independence from applications programs
· Improved data access to users through use of host and query languages
Disadvantages of Databases
· Database systems are complex, difficult, and time-consuming to design
· Substantial hardware and software start-up costs
· Damage to database affects virtually all applications programs
· Extensive conversion costs in moving form a file-based system to a database system
· Initial training required for all programmers and users
Syntax for DATABASE
· To create the database - CREATE DATABASE DB_NAME;
o Eg: CREATE DATABASE banking_system;
· To change to the newly created database – USE DB_NAME;
o Eg: USE banking_system;
· To check available list of databases
o SHOW DATABASES;
Note: Semicolon indicates the end of statement in SQL
Types of Database
· Analytic Database / Warehouse Database
· Operational Database
· Flat Files
Models of Database
· Hierarchical Database
· Network Database
· Relational Database
· Object / Relational Model
· Object-Oriented Model
· Semi structured Model
· Associative Model
· Entity-Attribute-Value (EAV) data model
· Context Model
· Distributed Database
Interview Questions
· Can you store data from a database to excel file without using any tool? How?
· What is the difference between transaction database and data warehouse databases?
· Difference between database & database server?
· What is Database Testing?
· What we test in Database Testing?
· What are the different stages involved in Database Testing?
· What SQL Statements have you used in Database Testing?
