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A relation may be in 2NF if
1. it is in 1NF &
2. Every non prime attribute functional dependent on primary attribute
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When is a table in 2NF?
A table is in 2NF when it is in 1NF and it includes no partial dependencies. However a table in 2NF may still have transitive dependencies, i.e., dependencies based on attributes that are not part of the primary key.
What is the domain of the inverse of a relation?
The domain of the inverse of a relation is the range of the relation. Similarly, the range of the inverse of a relation is the domain of the relation.
What is the Difference between relation schema and relation instance?
difference between relation sehema and relation instance in dbms
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.
Can you have a function that is not a relation?
No, a function must be a relation although a relation need not be a functions.
What is Normalization Explain the condition under which a relation needs to be normalized to 3 NF fro3 2 NF with the help of an example?
Define normalization explain the conditions under which a relation need to be normalized to 2nf and 3nf with the help of an example ?
When is a table in 2NF?
A table is in 2NF when it is in 1NF and it includes no partial dependencies. However a table in 2NF may still have transitive dependencies, i.e., dependencies based on attributes that are not part of the primary key.
What are the requirements for a relation to be in Second Normal Form?
A relation is in second normal form (2NF) if any of the following conditions apply: The primary key consists of only one attribute No non-primary key attribute exists in the relation Every non-primary key attribute is functionally dependent on the full set of primary key attributes
Explain suitable example 1NF 2NF 3NF?
. Explain 3 NF using suitable examples.
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 are the three primary components of a form in Modern database management?
the three forms of database are in normalization called 1NF, 2NF, and 3NF
What kind of normal form data does the object-oriented database handle?
BCNF, 3NF, 2NF, 1NF Non First Normal Form Both
What is the population of Llangadog Wales?
1303 in 2001The resident population of Llangadog, as measured in the 2001 Census, was 1951 of which 49% were male and 51% were female.http://piurl.com/2Nf
Where is the Lawley Extension situated?
I believe the Lawley Extension is situated in England,see address below for the Telford Steam Railway:The Old Loco ShedBridge RoadHorsehayTelfordShropshireTF4 2NF
What are the disadvantages of 1NF and 2NF?
First Normal Form Disadvantages:It cannot support multi valued attributes.It does not suffer from redundancy and having no limit to placed on a number of values
What is the different kinds of relation?
good relation, bad relation... also known as suck relation. fun relation, sex relation, happy relation, blood relation.
Different normalisation forms in database?
There are several normal forms are available in DBMS.those are1NF,2NF,3NF,BCNF,4NF,PJNF(project Join),DKNF(Domain Key).
