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A relation is in second normal form (2NF) if any of the following conditions apply:
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The primary key consists of only one attribute
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No non-primary key attribute exists in the relation
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Every non-primary key attribute is functionally dependent on the full set of primary key attributes
What else can I help you with?
What is minimal normal form a relation must satisfy in dbms?
Third normal form.
What are different normal forms?
There are 4 normal forms in databases. First normal form, second, third and fourth normal forms are there.
What are the differences between the first normal form and the second normal form?
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What are the different types of form?
First normal form, second normal form, third normal form, fourth normal form, fifth normal form and Boyce Codd normal form. See the related question below.
What are the different types of normal forms?
First normal form, second normal form, third normal form, fourth normal form, fifth normal form and Boyce Codd normal form. See the related question below.
What do most database designer prefer 1NF 2NF or 3NF?
First normal form (1NF) sets the very basic rules for an organized database: * Eliminate duplicative columns from the same table. * Create separate tables for each group of related data and identify each row with a unique column or set of columns (the primary key). Second normal form (2NF) further addresses the concept of removing duplicative data: * Meet all the requirements of the first normal form. * Remove subsets of data that apply to multiple rows of a table and place them in separate tables. * Create relationships between these new tables and their predecessors through the use of foreign keys. Third normal form (3NF) goes one large step further: * Meet all the requirements of the second normal form. * Remove columns that are not dependent upon the primary key. Finally, fourth normal form (4NF) has one additional requirement: * Meet all the requirements of the third normal form. * A relation is in 4NF if it has no multi-valued dependencies. Remember, these normalization guidelines are cumulative. For a database to be in 2NF, it must first fulfill all the criteria of a 1NF database.
Discuss the following concepts of normalization with examples need for normalization first normal form second normal form third normal form?
discussed
What is second normal form in DBMS?
Second normal form is valid in a table which have composite primary key which is made with the combination of two columns.So if we have A,B,C,D,E attributes in our table and C,D are fully functional dependent on A,B.But E is partially functional dependent on A,B,Mean if we use Only B to define E coloumn then that will be suffecent.so then we use 2nd normal form & we create two tables with coloumns attributes A,B,C,D and the other table with coloumns attribute B,E.That will be called second normal form.
What is a third normal form?
Third normal form is used to describe a database that has been normalized. Normalization is a process of removing redundant data. A third normal form is a database that has no transitive dependencies and has all the characteristics of the second normal form.
Explain the first 3 normal forms in dbms?
First Normal Form: Remove the repeating groups in a table Second Normal Form: Remove partial dependencies Third Normal Form: Remove transitive depedencies
Is a database that is in third normal form automatically in first and second normal form?
Yes, each normal form builds upon the lower forms, such that a database in form N will also be in form N-1, N-2, etc. A database in fifth normal form, for example, will also be in first through fourth normal forms.
What is the difference between 3NF and BCNF?
Boyce-codd normal form(BCNF) was proposed as a simpler form of 3NF,but it was found to be stricter than 3NF,because every relation in BCNF is also in 3NF.However a relation in 3NF is not necessarily in BCNF.
