Introduction to Database Systems

Database Management (Unit-1) | 4331603
Unit - I: Introduction to Database Systems (Marks-10)
 Define DBMS and Information 02 – Summer-2021, Winter-2020
 Define Database and Database Management System. 02 – Summer-2020, Winter-2018
 Define Metadata. 02 – Summer-2020, 2019, 2018, 2017, 2016, Winter-2019, 2018
 Define followings: (1) Metadata (2) System Catalog (3) Data Warehouse 03 – Winter-2020
Define the following terms
1. Data: Data means known facts that can be recorded or stored and have implicit meanings.
 Example, consider data of students: enroll no, name, address, contact no. and Marks of subjects,
result.

2. Information: Information means organized data, which can be derived from data.
 Example, Result of students (Pass or Fail): Student_1 = Pass, Student_2 = Fail.

Data Information
Data Means knows facts, that can be recorded
Information means processed or organized data
and have implicit meaning
Examples:
Examples:
• Student No: 12
• Percentage : 81.31%
• Student Name: ABC
(Derived from the marks of all subjects)
• City name : Rajkot
• Run rate in cricket match : 5.3 run/over
• Account No: 123456789
(Derived from total runs and overs)
• Balance : 10000
Row materials used to derive information Product derived from Data
Less Useful More Useful

3. Database (DB): It is a collection of inter-related data or table.
 Example, Books Database in Library, Student Database in University etc.
 Operations performed on database systems
o Create a database or table
o Insert or add new row(data) into existing database
o Modify (Change) data in existing database
o Remove (Delete) data in existing database
o Retrieve (Display) data from database
o Destroy (Delete) a database or table

4. DBMS (Database Management System): A database management system is a collection of inter-
related data and a set of programs to manipulate those data.
(DBMS = Database + Set of programs)
 Example, College Management System, Banking System.



Department of Information Technology [Ms. Nikita A. Patel] 1

, Database Management (Unit-1) | 4331603
 Database Management System (DBMS) is a software designed to define, manipulate, retrieve and
manage data in a database. Example, MS SQL Server, Oracle, My SQL, SQLite, etc.

5. System: Programs or tools used to manage database
 Example, SQL Server Studio, Oracle 11g

6. Metadata: data about data is called metadata.
 In other words, set of data that describes and gives information about another data. Example is given
student table below for metadata.
 Data such as table name, column name, datatype, and authorized user for any table is called metadata
for that table.
Table: Faculty

Emp_Name Address Mobile_No Subject
Prof. Ajay Shah Rajkot 9876543210 DS
 Metadata of above table is:
 Table name such as Faculty
 Column name such as Emp_Name, Address, Mobile_No, Subject
 Datatype such as Varchar, Decimal
 Access privileges such as Read, Write (Update)

7. System Catalog:* The system catalog is a container for a metadata. A system catalog is available for
each database.
 It is system-created database means created by DBMS itself.

 What is Data Dictionary? 02 – Winter-2019, 2018, Summer-2019, 2016
 What is Data Dictionary? Explain with its components. 03 – Winter-2021, 2020, 2018, Summer-
2021
8. Data dictionary: data dictionary is a file that contains metadata that is usually a part of the system
catalog.
 It is an information repository which contains metadata.
 This can involves information such as table name, owners, column names, datatypes, size and
constraints.
Table: Faculty

Emp_Name Address Mobile_No Subject
Prof. Ajay Shah Rajkot 9876543210 PPS
 Data Dictionary stores and manages following types of information:
 Store all logical information of database (table name, column name, data types, size etc.)

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, Database Management (Unit-1) | 4331603
 Store detail of physical location of database
 Store database user name, their responsibility
 Store description of database transactions (operations perform on database)
 Store detail of relationships among different tables

 Components of data dictionary:
 Entities - An entity is a "thing" or "object" or “person” in the real world, that is different
from other objects, exists physically or conceptually (Logically)
 Example, any particular student ‘Diya’ no ‘03’ can be considered as an entity.
 Attribute: - Property or characteristic of entity.
 Example, Studentno, Name, Address are attributes of entity student
 Relationship: - Connection or link between among entities.
 Key: A data item or field which is used to identify a record in a database is called Key.
 Primary Key: It is used to identify a record Example, EnrollNo acts as a Primary key for
students.
 Foreign Key: It is set of one or more columns whose values derived from primary key of other
table.




 Types of data dictionary? 02 – Winter-2021
 Differentiate between active and passive data dictionary 04 – Summer-2018, 2017
 Types of Data Dictionary

Active Data Dictionary Passive Data Dictionary
Created and maintained automatically by the Managed by users used more during design and
DBMS. development stage.

Also called integrated data dictionary. Also called non-integrated data dictionary.
It is always consistent with current definition It may not be consistent with current definition
and structure of database. Because, it’s managed and structure of database. Because, it’s require
by dbms itself. explicit changes.

9. Data Item or Fields: It is a character or group of characters that has a specific meaning.
 For example, the value of Emp_Name, Address, Mobile_No etc are all fields of Faculty table.

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