Module 2 - Relational Data Concepts

Question 1

Relational Data Explained

Answer 1

• In a relational database, real-world entities are represented as tables.
• An entity can be an object or an event.
• Each column holds a particular datatype:
• Text, Float, Int, Data/Time

Question 2

Normalization Explained

Answer 2

Minimizes data duplication and enforces data integrity.
- In practice
- Separate each entity into its own table.
- Separate each attribute into its own column.
- Uniquely identify each entity instance using a primary key.
- Use foreign key columns to link related entities.

Question 3

SQL Explained

Answer 3

Structured Query Language is the language used to interact with a relational database.

Question 4

SQL statement types

Answer 4

• DDL Data Definition Language
• DCL Data Control Language
• DML Data Manipulation Language

Question 5

Data Definition Language (SQL statements)

Answer 5

Manage tables, stored procedures, views and more.
- Create:
- Create a new object in the database, such as a table or a view.
- Alter:
- Modify the structure of an object. Add a new column for example.
- Drop:
- Remove an object from the database.
- Rename:
- Rename an existing object.

Question 6

Data Control Language (SQL statements)

Answer 6

Control access to database objects
- Grant:
- Grant permission to perform specific actions
- Deny:
- Deny permission to perform specific actions
- Revoke:
- Remove a previously granted permission

Question 7

Data Manipulation Language (SQL statements)

Answer 7

Working with the rows stored in tables
- Select:
- Read rows from a table
- Insert:
- Insert new rows into a table
- Update:
- Modify data in existing rows
- Delete:
- Delete existing rows

Question 8

Database Objects List

Answer 8

• Tables
• Views
• Stored Procedures
• Indexes

Question 9

Views (Database Objects)

Answer 9

A virtual table, that is the result of a Select query.
A way to present specific data from one or more tables as a single, unified object.
- You can select from this.

Question 10

Stored Procedures (Database Objects)

Answer 10

Collection of SQL statements that can be run on demand. Encapsulate logic within the database.

Question 11

Indexes (Database Objects)

Answer 11

Data structure to make locating values in a table faster.