Database Concepts

DATABASE CONCEPTS

• Records (Rows)
• Fields (Columns)
• Tables
• Files
• DBMS

• Columns also known as Fields
• A record is a group of related fields. A key field or primary key is a field that uniquely identifies each record in a file.
• We can define FIELD as smallest unit in a database
• Note that FIELDs may or may not be of the same type
• Record of a student consists of 6 Fields
• Computer based databases are usually organized into one or more tables
• A table is collection of ROWs and COLUMNs
• Data is stored in a database for easy access and retrieval

Database of Movies

DBMS (DATABASE MANAGEMENT SYSTEM)

DBMS is a set of programs to access data. Database management involves creating, modifying, deleting and adding data in files and using this data to generate reports or answer queries. DBMS software that allows us to perform these functions easily is called DBMS.

DBMS software available are as follows:

• MS-ACCESS
• IMB DB2
• dBASE III Plus
• SQL
• MySQL
• Oracle

DATABASE ADVANTAGES

• Reduces redundancy i.e. reduces repetition of data
• Restricts unauthorized users (through user ID and password)
• Sorting, querying, changing data will be easier
• Database provides backup and recovery facilities
• Reduced data entry, storage and retrieval costs
• Easy access to data
• Quicker application development
• Sharing of data

DATABASE DISADVANTAGES

• Database systems are complex, difficult and time consuming to design
• Hardware, software start-up costs
• An IT expert is required
• Initial training required for all programmers and users
• For small and simple applications a database system is often not advisable

DATABASE APPLICATIONS

• Banking: info about their customers and their accounts
• Airlines, reservations and travels
• Universities: registration, grades, library management
• Sales, customers, products and purchases
• PoS (Point of Sales) in shops: online purchase of goods
• Historical records
• Payroll systems: for processing salaries and benefits of employees