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DBMS
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Databases Engineering
47 followers study24x7 26 Mar 2019 04:44 PM study24x7 study24x7
Boyce-Codd Normal Form (BCNF) | Database Normalization | DBMS:https://youtu.be/NNjUhvvwOrk
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47 followers study24x7 26 Mar 2019 04:43 PM study24x7 study24x7
Normal Form (4NF) | Multi-Valued Dependency | Database Normalizationhttps://youtu.be/OTCuykFHBeA
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47 followers study24x7 26 Mar 2019 04:42 PM study24x7 study24x7
Third Normal Form (3NF) | Database Normalization | DBMShttps://youtu.be/aAx_JoEDXQA
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47 followers study24x7 26 Mar 2019 04:42 PM study24x7 study24x7
Second Normal Form (2NF) | Database Normalization | DBMS https://youtu.be/R7UblSu4744
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47 followers study24x7 26 Mar 2019 04:41 PM study24x7 study24x7
First Normal Form (1NF) | Database Normalization | DBMShttps://youtu.be/mUtAPbb1ECM
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47 followers study24x7 26 Mar 2019 04:40 PM study24x7 study24x7
Basic Concept of Database Normalization - Simple Explanation for Beginners
https://youtu.be/xoTyrdT9SZI
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47 followers study24x7 26 Mar 2019 04:36 PM study24x7 study24x7
Basic concept of NORMALIZATION | DBMShttps://youtu.be/oylHRgBDfNc
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47 followers study24x7 26 Mar 2019 04:34 PM study24x7 study24x7
Functional Dependency and its properties in DBMS in HINDI | DATE BASE MANAGEMENT SYSTEMhttps://youtu.be/qn5neFBpU40
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47 followers study24x7 26 Mar 2019 04:33 PM study24x7 study24x7
functional dependency in dbmshttps://youtu.be/X3c1phdyjbU
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47 followers study24x7 26 Mar 2019 04:31 PM study24x7 study24x7
Closure Set of Attributes in DBMS in HINDI | How to find Closure Of Attributes algorithmhttps://youtu.be/fT0QMtgqPrU
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47 followers study24x7 26 Mar 2019 04:31 PM study24x7 study24x7
Functional Dependency Practice Problems with solutions in HINDI example exercise solutionhttps://youtu.be/y8XuGhEdslM
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47 followers study24x7 26 Mar 2019 04:30 PM study24x7 study24x7
Functional Dependency in DBMS in HINDI | DATE BASE MANAGEMENT SYSTEMhttps://youtu.be/wez3fXrjBAE
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47 followers study24x7 26 Mar 2019 02:39 PM study24x7 study24x7

Types of Functional Dependencies :
Trivial functional dependency
non-trivial functional dependency
Multi-valued dependency
Transitive dependency

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47 followers study24x7 26 Mar 2019 02:36 PM study24x7 study24x7

Functional dependency in DBMS :
The attributes of a table is said to be dependent on each other when an attribute of a table uniquely identifies another attribute of the same table.

For example: Suppose we have a student table with attributes: Stu_Id, Stu_Name, Stu_Age. Here Stu_Id attribute uniquely identifies the Stu_Name attribute of student table because if we know the student id we can tell the student name associated with it. This is known as functional dependency and can be written as Stu_Id->Stu_Name or in words we can say Stu_Name is functionally dependent on Stu_Id.

Formally:
If column A of a table uniquely identifies the column B of same table then it can represented as A->B (Attribute B is functionally dependent on attribute A)

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47 followers study24x7 26 Mar 2019 11:08 AM study24x7 study24x7

Normalization :

Normalization.pdf
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47 followers study24x7 26 Mar 2019 11:00 AM study24x7 study24x7

Boyce Codd normal form (BCNF): It is an advance version of 3NF that’s why it is also referred as 3.5NF. BCNF is stricter than 3NF. A table complies with BCNF if it is in 3NF and for every functional dependency X->Y, X should be the super key of the table.

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47 followers study24x7 26 Mar 2019 11:00 AM study24x7 study24x7

Third Normal form (3NF) :A table design is said to be in 3NF if both the following conditions hold:


Table must be in 2NF
Transitive functional dependency of non-prime attribute on any super key should be removed.
An attribute that is not part of any candidate key is known as non-prime attribute.


In other words 3NF can be explained like this: A table is in 3NF if it is in 2NF and for each functional dependency X-> Y at least one of the following conditions hold:
X is a super key of table
Y is a prime attribute of


attribute that is a part of one of the candidate keys is known as prime attribute.

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47 followers study24x7 26 Mar 2019 10:50 AM study24x7 study24x7

Second normal form (2NF) :A table is said to be in 2NF if both the following conditions hold:
Table is in 1NF (First normal form)
No non-prime attribute is dependent on the proper subset of any candidate key of table.
An attribute that is not part of any candidate key is known as non-prime attribute.

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47 followers study24x7 26 Mar 2019 10:49 AM study24x7 study24x7

First normal form (1NF) :
As per the rule of first normal form, an attribute (column) of a table cannot hold multiple values. It should hold only atomic values.


Example: Suppose a company wants to store the names and contact details of its employees. It creates a table that looks like this:



This table is not in 1NF as the rule says “each attribute of a table must have atomic (single) values”, the emp_mobile values for employees Jon & Lester violates that rule.

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47 followers study24x7 26 Mar 2019 10:46 AM study24x7 study24x7

Normalization :
Here are the most commonly used normal forms:
First normal form(1NF)
Second normal form(2NF)
Third normal form(3NF)
Boyce & Codd normal form (BCNF)

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