Chapter one Mysql

Question 1

What is a database?

Answer 1

A very large collection of related data

Question 2

Database Management System (DBMS):

Answer 2

A Software package/system designed to define, manipulate, Retrieve , and manage data in a database

Question 3

Why Study Database?

Answer 3

Shift from computation to data (information)
- Always true for corporate computing
- More and more true in the scientific world
- Web
- social media generate ever increasing amount of data,
sensor devices generate also huge datasets
Including DBMS encompasses much of CS in a practical discipline
l OS, languages, theory, logic

Question 4

Data Models

Answer 4

Data modelling is a way for describing data, data relationships, data semantics, data constraints there is four different categories

Question 5

Starting off with number one Relational model?

Answer 5

In a relational model a table is known as a relation
- All the data is stored in various tables the columns and attributes are commonly the top names such as dept_name and salary

Question 6

What is a database schema

Answer 6

It is a description of a database, which is specified during database design and is not expected to change to frequently
= The information stored in the catalog

Question 7

Database State

Answer 7

The data in the database at a particular moment, also called the current set of instances.
= The data currently in the database

Question 8

Three schemas Physical level

Answer 8

describes how a record (e.g., instructor) is stored in a
storage media

Question 9

Three schemas Logical level

Answer 9

describes data stored in database, and the relationships
among the data

Question 10

Three schemas View level

Answer 10

application programs hide details of data types. Views can
also hide information (such as an employee’s salary) for security
purposes.

Question 11

Data Definition Language (DDL)

Answer 11

Data Definition Language (DDL)
- Specification notation for defining the database schema

Question 12

Data Manipulation Language (DML)

Answer 12

Language for accessing and manipulating the data as organized by the appropriate data model.
Example From the textbook
- Retrieval of information stored in the database
- Insertion of new information into the database
- Deletion of information stored in the database
- Modification of information stored in the database

Question 13

Two Types of data-manipulation languages Procedural

Answer 13

It requires a user to specify what data are
needed and how to get those data (steps such as 1. go to kitchen 2, get the sugar and milk, 3 mix and cook over fire, 4 put it in the cup and bring it)

Question 14

Two Types of data-manipulation languages Nonprocedural / Declarative

Answer 14

It requires a user to specify what data are needed without specifying how to get those data. (1. Get me a cup of Tea)

Question 15

Data Dictionary

Answer 15

Data dictionary contains metadata
From text book it Stores metadata about the structures of the database, in particular the schema of the database

Question 16

Database Design

Answer 16

The process of designing the general structure of the database
such as
- Conceptual Design
- Logical Design
- Physical Design

Question 17

Conceptual Database Design

Answer 17

• Identifies important entities and the high-level relationships among them.
• No attribute/column is specified.
• No primary key is specified

Question 18

Logical Database Design

Answer 18

 Performed using E-R diagram & relational model.
 Attributes are specified.
 Primary keys are identified.
 Constraints are mentioned