Datahåndtering og analyse
INF230
Srivatsav Saravanan
I am currently pursuing a Master’s
degree in Data Science, further. My
goal is to transition into a data-driven
role, where I can leverage my
technical expertise to extract valuable
insights and support data-driven
decision-making.
I hold a Bachelor’s degree in
Computer Science and Engineering,
specializing in Database Management
Systems and Python Programming.
Sheikh Hasan Elahi
I am currently doing my Master’s in
Data Science at NMBU. I completed
my Bachelor’s in Computer Science
with a specialization in data science,
where I developed a strong foundation
in programming, data analysis, and
machine learning. My main interests
are in predictive modeling, applied
statistics, and exploring how AI can be
used in practical settings. As your
teaching assistant, I look forward to
working with you, answering your
questions, and supporting you
throughout the course.
Habib Ullah
Associate Professor, from 2020
NMBU, Norway
PostDoc Researcher, 2020 - 2020
The Arctic University of Norway
Assistant Professor, 2016-2020
University of Ha’il, Saudi Arabia
PhD in ICT, 2011 - 2015
University of Trento, Italy
MSc, 2007 - 2009
Hanyang University, South Korea
INF230 - Course
• Class Lectures
– Main dependency is on slides
– Material for individual classes will be provided.
INF230 - Course
• Class (Theory)
https://www.w3schools.com/mysql/default.asp
• Lab Exercises (Practical)
– MySQL Workbench
– Assignment submission is compulsory
Final Exam
Grading Policy
3 hours written exam. AF.
Compulsory Lab Assignments (Average 60% score at least)
Students’ expectations
Complete Course Plan - Schedule
Complete Lab Plan - Schedule
Consistency between Course and Lab Plans
Interactive and Supportive Learning
Environment
Regular, Clear, Fast Communication
Assessment Fairness
Opportunities for Collaboration
Final Exam - Samples
Students’ expectations
Average 60% each or all assignments?
Final exam on SQL software ?
How many questions in final exam?
Do we have to write in final exam ?
What does compulsory assignment mean ?
ChatGPT or other tools are allowed ?
What are my expectations
My expectations
Please perform course evaluation at the end
of the course.
Outline
What is a database ?
Integrity, Implementation, Durability
Database-Management System (DBMS)
Data Abstraction/Data Models
Data Manipulation Language (DML)/Data
Definition Language (DDL)
Relational Databases
Databases
Database
Organized collection of inter-related data that
models some aspect of the real-world.
Databases are the core component of most
computer applications
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
Databases
Database
Organized Collection: A database is not just a random pile of data; it is carefully organized and
structured. Data is arranged in tables or other data structures to make it easily accessible and
manageable.
Inter-Related Data: In a database, different pieces of data are linked or related to each other in a
meaningful way. This helps in efficient retrieval and analysis of information.
Models Some Aspect of the Real World: The purpose of a database is to represent and emulate
some part of the real world. For example, a database for a library models the real-world library with
information about books, authors, borrowers, due dates, etc.
Databases
Database: Example
Consider an online bookstore. The bookstore's database models some aspects of the real-world
bookstore operations.
Organized Collection: The database contains structured tables for books, authors, customers,
orders, and more. Each table stores specific information about these aspects.
Inter-Related Data: Data in the database is linked together. For instance, a book record may be
related to an author record through a unique author ID. An order record may be related to a
customer record through a customer ID.
Models Some Aspect of the Real World: The database represents the bookstore's operations in the
real world. It tracks books, their availability, customer orders,
Databases
A simple database
Databases
A complicated database
Databases
The Internet revolution of the late 1990s sharply increased direct user
access to databases.
When you access an online bookstore and browse a book or
music collection, you are accessing data stored in a database.
When you enter an order online, your order is stored in a database.
When you access a bank Web site
and retrieve your bank balance and transaction information, the
information is
retrieved from the bank’s database system.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Example
Database example
Create a database that models a digital music store
to keep track of artists and albums.
Things we need store:
→ Information about Artists
→ What Albums those Artists released
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
Example
Database example
Store our database as comma-separated value
(CSV) files that we manage in our own code.
→ Use a separate file per entity.
→ The application has to parse the files each time they want
to read/update records.
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
Example
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
Example
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
Example – Data Integrity
How do we ensure that the artist is the same for
each album entry?
What if somebody overwrites the album year with
an invalid string?
How do we store that there are multiple artists on
an album?
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
Example – Implementation
How do you find a particular record?
What if we now want to create a new application
that uses the same database?
What if two threads try to write to the same file at
the same time?
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
Example – Durability
What if the machine crashes while our program is updating a
record?
What if we want to replicate the database on multiple
machines for high availability?
Source: Database Systems, CMU 15-445/645, https://15445.courses.cs.cmu.edu/fall2019/
The Answer is:
Database
Management
System (DBMS)..
Database-Management
System
❑ A DBMS is software that allows applications
to store and analyze information in a
database.
❑ A general-purpose DBMS is designed to
allow the definition, creation, querying,
update, and administration of databases
that is both convenient and efficient.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database-Management
System
https://www.smartsheet.com/database-management
Database-Management
System
https://www.proprofs.com/quiz-school/story.php?title=mis-chapter-3
Database-Management
System
Thus, although user interfaces hide details of access to a database, and most people are not
even aware they are dealing with a database, accessing databases forms an essential part of
almost everyone’s life today.
DBMS
Vendor
MySQL
Freeware
SQL Server
Microsoft
Oracle Lite
Oracle
IMS DB
IBM
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database-Management
System
Data redundancy. The same information may be duplicated in several places (files). For
example, if a student has a double major (say, music and mathematics) the address and
telephone number of that student may appear in a file that consists of student records of
students in the Music department and in a file that consists of student records of students in the
Mathematics department. This redundancy leads to higher storage and access cost.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database-Management
System
Data inconsistency. In addition, it may lead to data inconsistency; that is, the various copies
of the same data may no longer agree. For example, a changed student address
may be reflected in the Music department records but not elsewhere in the
system.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database-Management
System
Integrity problems. The data values stored in the database must satisfy certain
types of consistency constraints. Suppose the university maintains an
account for each department, and records the balance amount in each account.
Suppose also that the university requires that the account balance of a
department may never fall below zero. Developers enforce these constraints
in the system by adding appropriate code in the various application programs.
However, when new constraints are added, it is difficult to change
the programs to enforce them. The problem is compounded when constraints
involve several data items from different files.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database-Management
System
Data Abstraction
Physical level. The lowest level of abstraction describes how the data are actually stored. The
physical level describes complex low-level data structures in detail.
Logical level. The next-higher level of abstraction describes what data are stored in the
database, and what relationships exist among those data. The logical level thus describes the
entire database in terms of a small number of relatively simple structures.
View level. The highest level of abstraction describes only part of the entire database. Even
though the logical level uses simpler structures, complexity remains because of the variety of
information stored in a large database. Many users of the database system do not need all this
information; instead, they need to access only a part of the database. The view level of
abstraction exists to simplify their interaction with the system. The system may provide
many views for the same database.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Data Abstraction
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Data Abstraction
Applicatoin Developers
Database Designers
Database Administrators (DBAs)
https://binaryterms.com/view-of-data.html
Instance and Schema
Databases change over time as information is inserted and deleted. The collection
of information stored in the database at a particular moment is called an instance
of the database. The overall design of the database is called the database schema.
Schemas are changed infrequently, if at all.
The concept of database schemas and instances can be understood by analogy
to a program written in a programming language. A database schema corresponds
to the variable declarations (along with associated type definitions) in a program.
Each variable has a particular value at a given instant. The values of the variables
in a program at a point in time correspond to an instance of a database schema.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Instances
https://www.researchgate.net/figure/An-example-database-instance_fig1_220282752
Schemas
https://afteracademy.com/blog/what-is-a-schema
Data Models
Underlying the structure of a database is the data model: a collection of conceptual
tools for describing data, data relationships, data semantics, and consistency
constraints. A data model provides a way to describe the design of a database at
the physical, logical, and view levels.
Data models in DBMS:
Hierarchical Model.
Network Model.
Entity-Relationship Model.
Relational Model.
Object-Oriented Data Model.
Object-Relational Data Model.
Flat Data Model.
Semi-Structured Data Model.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Data Models
Hierarchical
Model.
Object-Oriented
Data Model.
https://www.scaler.com/topics/dbms/data-models-in-dbms/
https://afteracademy.com/blog/what-is-data-model-in-dbms-and-what-are-its-types/
https://www.geeksforgeeks.org/basic-object-oriented-data-model/
Data Models
Relational Model. The relational model uses a collection of tables to represent
both data and the relationships among those data. Each table has multiple
columns, and each column has a unique name. Tables are also known
as relations. The relational model is an example of a record-based model.
Record-based models are so named because the database is structured in
fixed-format records of several types. Each table contains records of a particular
type. Each record type defines a fixed number of fields, or attributes.
The columns of the table correspond to the attributes of the record type. The
relational data model is the most widely used data model, and a vast majority
of current database systems are based on the relational model.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Data Models – Relational Model
Data Models
Entity-Relationship Model. The entity-relationship (E-R) data model uses a
collection of basic objects, called entities, and relationships among these objects.
An entity is a “thing” or “object” in the real world that is distinguishable
from other objects. The entity-relationship model is widely used in database
Design.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Data Models
Entity-Relationship Model
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database Language
A database system provides a data-definition language (DDL) to specify the database
schema and a data-manipulation language (DML) to express database queries and updates.
In practice, the data-definition and data-manipulation languages are not
two separate languages; instead they simply form parts of a single database language,
such as the widely used SQL language.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database Language
A data-manipulation language (DML) is a language that enables users to access
or manipulate data as organized by the appropriate data model. The types of access are:
• Retrieval of information stored in the database
• Insertion of new information into the database
• Deletion of information from the database
• Modification of information stored in the database
A query is a statement requesting the retrieval of information.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Database Languages
https://www.wikitechy.com/tutorials/sql/sql-ddl
Relational Databases
A relational database is based on the relational model and uses a collection of
tables to represent both data and the relationships among those data. Most commercial
relational database systems employ the SQL language.
Each table has multiple columns and each column has a unique name. We present a sample
relational database below comprising two tables: one shows details of university instructors
and the other shows details of the various university departments.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Relational Databases
The relational model is an example of a record-based model. Record-based
models are so named because the database is structured in fixed-format records
of several types. Each table contains records of a particular type. Each record type
defines a fixed number of fields, or attributes. The columns of the table correspond
to the attributes of the record type.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Relational Databases
SQL language allows one to define tables. For instance, the following SQL statement defines
the department table:
create table department
(dept name char (20),
building char (15),
budget numeric (12,2));
Execution of the above statement creates the department table with three
columns: dept name, building, and budget, each of which has a specific data type
associated with it.
Source: Database Systems Concepts, Avi Silberschatz, Henry F. Korth, S. Sudarshan
Thanks
Questions/Answers