Introduction to Databases: Lesson 1 Quiz

Data redundancy, data inconsistency, incompatible file format, difficulty in accessing data, separation and isolation of data, data integrity problems, problems with concurrent access by multiple users

A software package designed to create databases and manipulate data. It contains a collection of interrelated data and a set of programs to access the data.

Improved data sharing, increased productivity of application development, enforcement of application development, improved data quality, improved data accessibility and responsiveness, reduced program maintenance

Entities and attributes

Database relationships define the links between records in different tables, such as one-to-one, one-to-many, and many-to-many relationships.

A very large collection of logically related data that is organized to manipulate easily. Models real-world activities.

We need a database to organize and manipulate large collections of data, and to model real-world activities and relationships.

A software system that enables users to define, create, maintain, and control access to the database.

The elements of a database include entities (e.g. students, courses) and relationships (e.g. Madara is studying PLY B6).

PK stands for Primary Key, FK stands for Foreign Key, and Composite PK is a combination of multiple attributes that uniquely identify a record in a database table.

Telephone Directory Book = Reservation System Cupboard in a library = Library Management System Supermarket = Order Processing System Encyclopedia = University Management System

Entities (eg: students, courses) = Models real-world activities Relationships (eg: Madara is studying PLY B6) = Links between entities PK, FK and Composite PK = Key attributes in a database Referential Integrity = Ensures data consistency

DBMS = Manages databases and provides access to data Database Relationships = Define how data is connected or related to each other Physical Examples = Real-world instances of databases Database Applications = Systems that use databases for specific purposes

File Based Data Processing Systems = A collection of application programs that manage organization’s operational data on separate computer files Database Processing Systems = All applications interact with the same data in a centralized database

Data redundancy (duplication) = File Based Data Processing Systems Incompatible file format = File Based Data Processing Systems

Improved data sharing = Database Processing Systems Enforcement of application development = Database Processing Systems

Entities = The things we are going to save information about Attributes = A single item of information to be saved about that entity

Relation = A single file/table containing data about an entity Record = A row of the relation including information about a particular entity

One-to-one (1:1) = One occurrence of an entity relates to only one occurrence in another entity One-to-many (1:M) = One occurrence of an entity relates to multiple occurrences in another entity