CIT-407

1. CIT 407
T-SQL Queries Design and Tuning

2. What is a database

3. • an organized collection of structured data
• stored electronically in a computer system
• controlled by a database management system (DBMS)
• data, the DBMS and applications are referred as a
database system
• data is typically modeled in rows and columns
• in a series of tables to make processing and data
querying efficient
• data can then be easily accessed, managed, modified,
updated, controlled, and organized

4. • Relational databases use structured query language
(SQL) for writing and querying data.
• SQL is a programming language used by nearly
all relational databases to query, manipulate, and define
data, and to provide access control.
• SQL was first developed at IBM in the 1970s which led to
implementation of the SQL ANSI standard
• SQL has spurred many extensions from companies such
as IBM, Oracle, Microsoft, MySQL

5. There are many different types of databases
• Relational databases
• Object-oriented databases
• Distributed databases
• Data warehouses
• NoSQL databases
• Graph databases
• OLTP databases
• Open source databases
• Cloud databases
• Multimodel database
• Document/JSON database
• Self-driving databases

6. Relational databases
• Items in a relational database are organized as a
set of tables with columns and rows
• Relational database technology provides the
most efficient and flexible way to access
structured information

7. What is data modelling
• is the process of creating a data model for the data to be stored
in a database
• Conceptual representation of Data objects, the associations
between different data objects and the rules
• Data modeling helps in the visual representation of data and
enforces business rules, regulatory compliances, and
government policies on the data
• Data Models ensure consistency in naming conventions, default
values, semantics, security while ensuring quality of the data

8. The two types of Data Models techniques are
1. Entity Relationship (E-R) Model
2. UML (Unified Modelling Language)

9. There are three types of data models:
1. Conceptual
2. Logical
3. Physical

10. The main aim of this model is to establish the entities, their
attributes, and their relationships.
In this data modeling level, there is hardly any detail
available of the actual database structure.
Conceptual Model

11. The 3 basic tenants of Data Model are
Entity: A real-world thing
Attribute: Characteristics or properties of an entity
Relationship: Dependency or association between two
entities
Conceptual Model

12. For example:
• customer and product are two entities
• customer number and name are attributes of the
customer entity
• product name and price are attributes of product entity
• sale is the relationship between the customer and
product

13. customer name
customer number
product name
product price
sale
Entity relationship diagram

14. Customer buys
product from
website
product
A sale is recorded
Item is shipped to customer
Inventory gets replenished
Item is purchased
from suppliers