What is a Database and Why Use One?

Database Basics What is a database and how does it organize information? A database is a computerized system for storing information in an organized manner so that it can be searched for and retrieved when needed. Information is stored in the form of fields, records, and files. Unlike a list or spreadsheet, a database may store information that is more complicated than a simple list.

Sounds Like More Work, Not Less A relational database is more complicated than a list However, a relational database minimizes data redundancy, preserves complex relationships among topics, and aids data consistency Furthermore, a relational database provides a solid foundation for user forms and reports and allows the data to be examined in a myriad of different ways.

Data Duplication

Data Entry Errors

Database Basics Levels of Data within a Database Entity – a person, place, thing, or event Field – a single value, such as a name, address, or dollar amount data type: usually numeric or text (numbers and text) name: assigned by person developing the database size: number of characters that can be entered Record – related fields describing an entity File – collection of records of the same type

Database Basics Traditional database organizes data in a hierarchy. A field is the smallest element. Fields are within a record. Records are organized in a data file. Database is a collection of data files.

Databases and Relationships A relational database is a collection of related tables Records in the separate tables are connected through a common field A primary key is a field, or a collection of fields, that uniquely identify each record in a table Including the primary key from one table as a field in a second table to form a relationship between the two tables, it is called a foreign key in the second table

Introduction to Database Concepts

DBMS Related Tables

Relational Database Management Systems A database management system (DBMS) is a software program that lets you create databases and then manipulate the data they contain In a relational database management system, data is organized as a collection of tables. A relational DBMS controls the storage of databases and facilitates the creation manipulation, and reporting of data

Relational Database Management Systems A relational DBMS provides the following functions: Allows you to create database structures containing fields, tables, and table relationships Lets you easily add new records, change field values in existing records, and delete records Contains a built-in query language, which lets you obtain immediate answers to the questions (or queries) you ask about your data Contains a built-in report generator, which lets you produce professional-looking, formatted reports from your data Protects databases through security, control, and recovery facilities

End of Intro