Database Theory and Design

An organized collection of related data

Software that manages and controls access to the database

Program that interacts with the database at some point in its execution

A collection of programs that interact with the database

• File-based System • Database System

A group of software tools that help users do different tasks. Each program stores and manages its own data separately

Software that helps store, manage, and organize data in an easy-to-access way. It allows users to save, update, and retrieve data quickly and securely

User Control - End user has total control of the stored data - Can modify application or data at will Applications and data file can be optimised for particular tasks

• Data duplication • Data dependence • Incompatible file formats • Proliferation of application programs (APPS)

If a record is duplicated in each of the 3 files, a change to the record requires a change to all 3 files. Integrity of student records may be compromised if the files are not all updated - which file holds the correct information.

The way data is stored affects how it can be used, making the data and the program tightly connected

If application programs are separatly implemented to data files, then the data files may be incompatible with the application program Meaning the data files would have to be translated to fit the application program

If you wanted more information out of data files than initially anticipated You would have to add more application programs to handle new queries Leading to the proliferation of files and application programs that each official has to handle

The data is stored in a DB, which is then accessed by DBMS. When officials need info from the DB they write queries in SQL to communicate with the DBMS which in turn gives them what they need

Software that interacts with users’ application programs and the DB

Software system that enables the user to define, create, maintain and control access to the database

Run applications to perform specific database operations

Use a programming language to provide the required functionality for the end users

Ensures the database is well-organized, secure, and works efficiently

Responsible for implementation and monitoring of the database

• Control of data redundancy • Data Consistency • Sharing of data • Improved data integrity • Improved Security • Enforcement of Standards • Economy of Scale • Balance of conflicting requirements • Improved data accessibility and responsiveness • Increased Productivity • Improved maintenance through data independence • Increased concurrency • Backup and Recovery services

Since all data is now stored in a single database, there are no unnecessary multiple copies of data

Only one copy of each data item (changes only have to be made to 1 item, therefore if there was multiple and they werent all changed data wouldnt be consistent)

Since data is common to the organization, it’s easy for all authorized users to have access to the same data