This document reviews key concepts in database theory including: what a database is, its components, and the different types of relationships between entities. It also discusses relational databases, the SQL language including its main components like DDL, DML, DQL, and DCL. Other topics covered include integrity constraints, normalization, and the advantages of normalization.

1. *Property of STI K0019
Review of Theory of
Databases
 Review of Database Concepts

2. *Property of STI K0019
Review of Database
Concepts
 What is a Database?
 A database is a collection of logically related data.
 Example: Personal information such as name, address, birthday
and gender
 What is a Schema?
 A schema or a database schema is the over-all design of a
database.
 What is a Database System?
 A database system is an automated system that enables users to
define, create, maintain and control access to the database.

3. *Property of STI K0019
Review of Database
Concepts
 What are the components of the DBMS Environment?
 Data
 Hardware
 Software
 End Users
 Procedure

4. *Property of STI K0019
Review of Database
Concepts
 What are the different facilities that DBMS provide?
 Users can define the database through a Data Definition
Language (DDL).
 Users can manipulate data through a Data Manipulation
Language (DML).
 DBMS can provide security system.
 DBMS can provide an integrity system.
 DBMS can provide a concurrency control system.
 DBMS can provide a recovery control system.

5. *Property of STI K0019
Review of Database
Concepts
 What are the different entity relationships?
 One-to-One

6. *Property of STI K0019
Review of Database
Concepts
 What are the different entity relationships?
 One-to-Many

7. *Property of STI K0019
Review of Database
Concepts
 What are the different entity relationships?
 Many-to-One

8. *Property of STI K0019
Review of Database
Concepts
 What are the different entity relationships?
 Many-to-Many

9. *Property of STI K0019
Review of Database
Concepts
 What is relational database?
 A relational database is divided into logical units called
table which is composed of rows and columns of data.

10. *Property of STI K0019
Review of Database
Concepts
 What is a relation?
 A relation is composed of rows and columns of data.
 What is an attribute?
 In relational database, the table columns correspond to
attributes.
 What is a domain?
 A domain refers to a set of valid atomic values for a given
attribute.
 What is a primary key?
 A primary key refers to an attribute or field that serves as a
unique identifier for a particular record within a relation.

11. *Property of STI K0019
Review of Database
Concepts
 What is SQL?
 Structured Query Language (SQL) is the standard
language used to define, query, update and maintain
relational databases.
 Main categories of SQL commands are as follows:
 Data Definition Language (DDL)
 Data Manipulation Language (DML)
 Data Query Language (DQL)
 Data Control Language (DCL)
 Transactional control commands

12. *Property of STI K0019
Review of Database
Concepts
 What is Data Definition Language (DDL)?
 The DDL allows the user to create and restructure database
objects.
 Some of the most fundamental DDL commands are:
 CREATE TABLE
 ALTER TABLE
 DROP TABLE
 CREATE INDEX
 ALTER INDEX
 DROP INDEX
 CREATE VIEW
 DROP VIEW

13. *Property of STI K0019
Review of Database
Concepts
 What is Data Control Language (DML)?
 DML allows the user to manipulate data within objects of
a relational database.
 The three basic DML commands are
 INSERT
 UPDATE
 DELETE
 What is Data Query Language (DQL)?
 DQL allows the user to select a data or a group of data.
 The base command is SELECT

14. *Property of STI K0019
Review of Database
Concepts
 What is Data Control Language (DCL)?
 The DCL allows the user to create objects related to user
access and also control the distribution of privileges
among users.
 Some data control commands are as follows:
 ALTER PASSWORD
 GRANT
 REVOKE
 CREATE SYNONYM

15. *Property of STI K0019
Review of Database
Concepts
 What is Transactional Control Commands (TCC)?
 The TCC allow the user to manage database
transactions.
 Some commands are as follows:
 COMMIT
 ROLLBACK
 SAVEPOINT
 SET TRANSACTION

16. *Property of STI K0019
Review of Database
Concepts
 What is Integrity Constraint?
 Integrity constraints are used to ensure accuracy and
consistency of data in a relational database.
 What are the types of integrity constraints?
 Primary key Constraints
 Unique Constraints
 Foreign Key Constraints
 Not Null Constraints
 Check Constraints

17. *Property of STI K0019
Review of Database
Concepts
 What is normalization?
 Normalization is a process of reducing data
redundancy in a database.
 The different levels of normal forms:
 First Normal Form (1NF)
 Second Normal Form (2NF)
 Third Normal Form (3NF)

18. *Property of STI K0019
Review of Database
Concepts
 What are the advantages of normalization?
 Better overall database organization
 Reduction of redundant data
 Data consistency within the database
 Flexible database design
 Efficient database security handling
 Enforces concept of referential integrity