DBMS NOTES
Disclaimer
The notes provided by me are based on my personal understanding
and interpretation of the material presented in class. While every
effort has been made to ensure accuracy and completeness, there is
a possibility that some topics may have been missed or certain
details may be incorrect or outdated. Additionally, the notes may
contain some information that may not be relevant or useful for your
specific needs. Therefore, it is recommended that these notes be
used as a supplement to your own study and research, and should
not be relied upon as the sole source of information for any
academic or professional purposes. The author of these notes
assumes no responsibility or liability for any errors, omissions, or
inaccuracies in the content provided.
,Lec-1
ER Model:
We are gonna use two models:
ER model and Relational model.
In the relational symbol we have p for production and n and m are for one to one or many to
one relation ship.
Attributes:
key attributes: the unique attribute that is used to identify any entity with a unique id, it is
underlined.
multivalued attributes: Attributes that can be more than once, for example our mobile number
is multi valued but we cannot change the colour of our car.
derived attributes: represented by dotted lines.
Train reservation ER model
Table name : customer
fields:
C_ID number(6)
C_name varchar(10)
C_Age number(2)
C_gender varchar(6)
C_DOB DATE
C_number number(10)
Table name:
Booking
Fields:
B_ID number(6)
C_ID number(6)
,D_OF_J DATE
D_OF_Booking DATE
Train_no number (5)
Start_Place varchar(15)
DP varchar(15)
Table name: Train
fields:
T_ID number(5)
Train_name varchar(15)
Days DATE/Varchar
Attribute that gets divided into more attributes further then it is called composite attributes.
There is something known as weak entity. If we do not have any key attribute for a particular
entity then it is called as weak entity.
Relationship :
First of all we need to find the indicator.
We need to draw the eclipse diagram in order to find the relation between entities, many to
one or one to one.
For reference :
https://s3.us-west-2.amazonaws.com/secure.notion-static.com/32e48ae8-b4b9-4810-a251-
807ddf227508/ER_Model_Guideline_.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-
Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIAT73L2G45EIPT3X45%2F20230224%2Fus-west-
2%2Fs3%2Faws4_request&X-Amz-Date=20230224T172441Z&X-Amz-Expires=86400&X-Amz-
Signature=4498bd7f6c39bcec8eca8eb1fdc40f398647269fd129a36bd7b383ac85828152&X-Amz-
SignedHeaders=host&response-content-
disposition=filename%3D%22ER%2520Model%2520Guideline%2520.pdf%22&x-id=GetObject
Lec-2
, There are two kinds of data:
Structured and
Unstructured
How much contact can we store in sim-card, phone memory and cloud storage that we have?
Sim cards:
The typical memory :
contacts: 250
sms : 50
refer:
https://www.quora.com/How-many-contacts-can-I-save-on-my-SIM-card
Phones internal memory :
Basically there is no limitation of the quantity of contacts if the storage is large enough.
How many contacts can I save in my phone? | Official Support | ASUS India
I-cloud:
• Total number of contact cards: 50,000
Limits for iCloud Contacts, Calendars, Reminders, Bookmarks, and Maps
Gmail :
contacts: 25000
We store data in rows and column.
DDL : data definition language, it works on frame and not data.
If we want to update the frame then we need to use alter.
Constraints are that makes our data valuable.
Lec-3
Disclaimer
The notes provided by me are based on my personal understanding
and interpretation of the material presented in class. While every
effort has been made to ensure accuracy and completeness, there is
a possibility that some topics may have been missed or certain
details may be incorrect or outdated. Additionally, the notes may
contain some information that may not be relevant or useful for your
specific needs. Therefore, it is recommended that these notes be
used as a supplement to your own study and research, and should
not be relied upon as the sole source of information for any
academic or professional purposes. The author of these notes
assumes no responsibility or liability for any errors, omissions, or
inaccuracies in the content provided.
,Lec-1
ER Model:
We are gonna use two models:
ER model and Relational model.
In the relational symbol we have p for production and n and m are for one to one or many to
one relation ship.
Attributes:
key attributes: the unique attribute that is used to identify any entity with a unique id, it is
underlined.
multivalued attributes: Attributes that can be more than once, for example our mobile number
is multi valued but we cannot change the colour of our car.
derived attributes: represented by dotted lines.
Train reservation ER model
Table name : customer
fields:
C_ID number(6)
C_name varchar(10)
C_Age number(2)
C_gender varchar(6)
C_DOB DATE
C_number number(10)
Table name:
Booking
Fields:
B_ID number(6)
C_ID number(6)
,D_OF_J DATE
D_OF_Booking DATE
Train_no number (5)
Start_Place varchar(15)
DP varchar(15)
Table name: Train
fields:
T_ID number(5)
Train_name varchar(15)
Days DATE/Varchar
Attribute that gets divided into more attributes further then it is called composite attributes.
There is something known as weak entity. If we do not have any key attribute for a particular
entity then it is called as weak entity.
Relationship :
First of all we need to find the indicator.
We need to draw the eclipse diagram in order to find the relation between entities, many to
one or one to one.
For reference :
https://s3.us-west-2.amazonaws.com/secure.notion-static.com/32e48ae8-b4b9-4810-a251-
807ddf227508/ER_Model_Guideline_.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-
Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIAT73L2G45EIPT3X45%2F20230224%2Fus-west-
2%2Fs3%2Faws4_request&X-Amz-Date=20230224T172441Z&X-Amz-Expires=86400&X-Amz-
Signature=4498bd7f6c39bcec8eca8eb1fdc40f398647269fd129a36bd7b383ac85828152&X-Amz-
SignedHeaders=host&response-content-
disposition=filename%3D%22ER%2520Model%2520Guideline%2520.pdf%22&x-id=GetObject
Lec-2
, There are two kinds of data:
Structured and
Unstructured
How much contact can we store in sim-card, phone memory and cloud storage that we have?
Sim cards:
The typical memory :
contacts: 250
sms : 50
refer:
https://www.quora.com/How-many-contacts-can-I-save-on-my-SIM-card
Phones internal memory :
Basically there is no limitation of the quantity of contacts if the storage is large enough.
How many contacts can I save in my phone? | Official Support | ASUS India
I-cloud:
• Total number of contact cards: 50,000
Limits for iCloud Contacts, Calendars, Reminders, Bookmarks, and Maps
Gmail :
contacts: 25000
We store data in rows and column.
DDL : data definition language, it works on frame and not data.
If we want to update the frame then we need to use alter.
Constraints are that makes our data valuable.
Lec-3
