Normalization and three normal forms.pptxZoha681526
Normalisation dbms computer science computer technology computer networks BCA bachelor of computer applications, normalisation is used to reduce the redundancy to avoid the anamolies there are 5 types of normal forms 1st normal form, second normal form, third normal form, boyce codd normal form, 4th normal form and fifth normal form
Normalization is a process of organizing the data in a database to avoid data redundancy, insertion anomaly, update anomaly & deletion anomaly.
--> 1NF
--> 2NF
--> 3NF
--> BCNF.
Normalization and three normal forms.pptxZoha681526
Normalisation dbms computer science computer technology computer networks BCA bachelor of computer applications, normalisation is used to reduce the redundancy to avoid the anamolies there are 5 types of normal forms 1st normal form, second normal form, third normal form, boyce codd normal form, 4th normal form and fifth normal form
Normalization is a process of organizing the data in a database to avoid data redundancy, insertion anomaly, update anomaly & deletion anomaly.
--> 1NF
--> 2NF
--> 3NF
--> BCNF.
Normalization is the process of removing redundant data from your tables to improve storage efficiency, data integrity, and scalability.
Normalization generally involves splitting existing tables into multiple ones, which must be re-joined or linked each time a query is issued.
Why normalization?
The relation derived from the user view or data store will most likely be unnormalized.
The problem usually happens when an existing system uses unstructured file, e.g. in MS Excel.
What is Database NormalizationExplain the guidelines for ensuring t.pdfarjunstores123
What is Database Normalization?Explain the guidelines for ensuring that database are
normalized.
Solution
Here is the answer for your respective question on database normalization:
Before going to know about database normalization we should know about database.
So what is a database?
Its like a repository where all the data related to a particular organization are stored inside the
tables in the form of columns and rows
which can be related to the employees working in that organization or about the finacial and
accounts of the company etc.
While storing data into the tables there might be some problems like duplicate entries of the
same record related to a particular person which creates a problem named data redundancy in the
database.
So to avoid this there\'s been introduced a concept named Normalization.
So what is Database Normalization?
Database normalization or simply called normalization, is the process of arranging or organizing
the columns
and tables of a relational database to reduce data redundancy and improve data integrity and
efficiency of data stored.
Normalization arranges attributes in tables based on dependencies between attributes,
ensuring that the dependencies are properly enforced by database integrity constraints.
Normalization can be achieved by applying some formal rules like synthesis or decomposition.
To come to the types of normalizations there are many.Some of them are as follows:
1NF - First Normal Form
2NF - Second Normal Form
3NF - Third Normal Form
BCNF - Boyce–Codd Normal Form
4NF - Fourth Normal Form
Basic guidelines for normalization:
1NF - First Normal Form:
As per First Normal Form, no two Rows of data must contain repeating group of information.
Each table should be organized into rows and each row should have a primary key that
distinguishes it as unique.
Example for 1NF:
Student Age Subject
Andrea 15 Zoology
Andrea 15 Social Studies
Alan 14 Maths
Stuart 17 Maths
But by using the First Normal Form, data redundancy increases,
as there will be many columns with same data in multiple rows but each row as a whole will be
unique.
2NF - Second Normal Form:
There must not be any partial dependency of any column on primary key.
Meaning that for a table that has concatenated primary key, each column in the table
that is not part of the primary key must depend upon the entire concatenated key for its
existence,failing which the table fails Second normal form.
Example:
Student Age
Andrea 15
Alex 14
Stuart 17
Here we should maintain a separate table for the value subject by doing which we can reduce
data redundancy which is lacking in 1NF.
In the above table,candidate key will be Student column, because all other column i.e Age is
dependent on it.
3NF - Third Normal Form:
Third normal form (3NF) is a database principle that allows you to properly
arrange our tables by building upon the database normalization principles provided by 1NF and
2NF.
There are two basic requirements for a database to be in third normal fo.
Database normalization is the process of refining the data in accordance with a series of normal forms. This is done to reduce data redundancy and improve data integrity. This process divides large tables into small tables and links them using relationships.
Here is the link of full article: https://www.support.dbagenesis.com/post/database-normalization
Normalization is the process of removing redundant data from your tables to improve storage efficiency, data integrity, and scalability.
Normalization generally involves splitting existing tables into multiple ones, which must be re-joined or linked each time a query is issued.
Why normalization?
The relation derived from the user view or data store will most likely be unnormalized.
The problem usually happens when an existing system uses unstructured file, e.g. in MS Excel.
What is Database NormalizationExplain the guidelines for ensuring t.pdfarjunstores123
What is Database Normalization?Explain the guidelines for ensuring that database are
normalized.
Solution
Here is the answer for your respective question on database normalization:
Before going to know about database normalization we should know about database.
So what is a database?
Its like a repository where all the data related to a particular organization are stored inside the
tables in the form of columns and rows
which can be related to the employees working in that organization or about the finacial and
accounts of the company etc.
While storing data into the tables there might be some problems like duplicate entries of the
same record related to a particular person which creates a problem named data redundancy in the
database.
So to avoid this there\'s been introduced a concept named Normalization.
So what is Database Normalization?
Database normalization or simply called normalization, is the process of arranging or organizing
the columns
and tables of a relational database to reduce data redundancy and improve data integrity and
efficiency of data stored.
Normalization arranges attributes in tables based on dependencies between attributes,
ensuring that the dependencies are properly enforced by database integrity constraints.
Normalization can be achieved by applying some formal rules like synthesis or decomposition.
To come to the types of normalizations there are many.Some of them are as follows:
1NF - First Normal Form
2NF - Second Normal Form
3NF - Third Normal Form
BCNF - Boyce–Codd Normal Form
4NF - Fourth Normal Form
Basic guidelines for normalization:
1NF - First Normal Form:
As per First Normal Form, no two Rows of data must contain repeating group of information.
Each table should be organized into rows and each row should have a primary key that
distinguishes it as unique.
Example for 1NF:
Student Age Subject
Andrea 15 Zoology
Andrea 15 Social Studies
Alan 14 Maths
Stuart 17 Maths
But by using the First Normal Form, data redundancy increases,
as there will be many columns with same data in multiple rows but each row as a whole will be
unique.
2NF - Second Normal Form:
There must not be any partial dependency of any column on primary key.
Meaning that for a table that has concatenated primary key, each column in the table
that is not part of the primary key must depend upon the entire concatenated key for its
existence,failing which the table fails Second normal form.
Example:
Student Age
Andrea 15
Alex 14
Stuart 17
Here we should maintain a separate table for the value subject by doing which we can reduce
data redundancy which is lacking in 1NF.
In the above table,candidate key will be Student column, because all other column i.e Age is
dependent on it.
3NF - Third Normal Form:
Third normal form (3NF) is a database principle that allows you to properly
arrange our tables by building upon the database normalization principles provided by 1NF and
2NF.
There are two basic requirements for a database to be in third normal fo.
Database normalization is the process of refining the data in accordance with a series of normal forms. This is done to reduce data redundancy and improve data integrity. This process divides large tables into small tables and links them using relationships.
Here is the link of full article: https://www.support.dbagenesis.com/post/database-normalization
3. Database Normalization
Database Normalization is a process
and it should be carried out for every
database you design. The process of
taking a database design, and apply a
set of formal criteria and rules, is
called Normal Forms.
4. process:
1. The first normal form
2. The second normal form
3. The third normal form
Of the three normal forms, each subsequent normal form
depends on
normalization steps taken in the previous normal form. For
example, to
normalize a database using the second normal form, the
database must first be
in the first normal form.
The Following Are The Three Most Common
Normal Forms In The Normalization
5. 1. The First Normal Form (1NF):
The first normal form requires that a table satisfies the
following conditions:
1. Rows are not ordered
2. Columns are not ordered
3. There is duplicated data
4. Row-and-column intersections always have a unique value
5. All columns are “regular” with no hidden values
In the following example, the first table clearly violates the 1
NF. It contains more
than one value for the Dept column. So, what we might do
then is go back to the
original way and instead start adding new columns, so,
Dept1, Dept2, and so on.
6. This is what’s called a repeating group, and there should be no repeating groups .
In order to bring this First Normal Form, split the table into the two tables. Let’s
take the department data out of the table and put it in the dept table. This has
the one-to-many relationship to the employee table.
Let’s take a look at the employee table:
8. Second Normal Form and Third Normal Form are all about the relationship
between the columns that are the keys and the other columns that aren’t the
key columns.
2.Second Normal Form (2NF):
An entity is in a second normal form if all of its attributes depend
on the whole primary key. So this means that the values in the
different columns have a dependency on the other columns.
1. The table must be already in 1 NF and all non-key columns of the tables must depend on the
PRIMARY KEY
2. The partial dependencies are removed and placed in a separate table
9. Note: Second Normal Form (2 NF) is only ever a problem when we’re using a
composite primary key. That is, a primary key made of two or more columns.
The following example, the relationship is established between the Employee
and Department tables.
10. In this example, the Title column is functionally dependent on Name and
Date columns. These two keys form a composite key. In this case, it only
depends on Name and partially dependent on the Date column. Let’s remove
the course details and form a separate table. Now, the course details are
based on the entire key. We are not going to use a composite key:
11. The third normal form states that you should eliminate fields in a table that do
not depend on the key.
A Table is already in 2 NF
Non-Primary key columns shouldn’t depend on the other non-Primary key
columns
There is no transitive functional dependency
Consider the following example, in the table employee; empID determines the
department ID of an employee, department ID determines the department
name. Therefore, the department name column indirectly dependent on the
empID column. So, it satisfies the transitive dependency. So this cannot be in
third normal form.
3.Third Normal Form (3NF):
12. In order to bring the table to 3 NF, we split the employee table into two.
13. Now, we can see the all non-key columns are fully functionally
dependent on the Primary key.
Although a fourth and fifth form does exist, most databases do
not aspire to use those levels because they take extra work and
they don’t truly impact the database functionality and improve
performance.