What is normalization and types of normalization?
Answer Posted / j geor
Database normalization is a technique for designing
relational database tables to minimize duplication of
information and, in so doing, to safeguard the database
against certain types of logical or structural problems,
namely data anomalies.
1NF Eliminate Repeating Groups - Make a separate table for
each set of related attributes, and give each table a
primary key.
2NF Eliminate Redundant Data - If an attribute depends on
only part of a multi-valued key, remove it to a separate table.
3NF Eliminate Columns Not Dependent On Key - If attributes
do not contribute to a description of the key, remove them
to a separate table.
BCNF Boyce-Codd Normal Form - If there are non-trivial
dependencies between candidate key attributes, separate them
out into distinct tables.
4NF Isolate Independent Multiple Relationships - No table
may contain two or more 1:n or n:m relationships that are
not directly related.
5NF Isolate Semantically Related Multiple Relationships -
There may be practical constrains on information that
justify separating logically related many-to-many relationships.
ONF Optimal Normal Form - a model limited to only simple
(elemental) facts, as expressed in Object Role Model notation.
DKNF Domain-Key Normal Form - a model free from all
modification anomalies.
| Is This Answer Correct ? | 165 Yes | 29 No |
Post New Answer View All Answers
What is use of trigger?
what is a constraint? Tell me about its various levels. : Sql dba
What are the different sql languages?
what is cursor. write example of it. What are the attributes of cursor.
How are sql commands classified?
What is sqlservr exe?
What is a join?
Is nosql faster than sql?
How does a self join work?
1) Synonyms 2) Co-related Subquery 3) Different Jobs in Plsql 4) Explain Plan 5) Wrap 6) Query Optimization Technique 7) Bulk Collect 8) Types of index 9) IF primary key is created then the index created ? 10) Foreign Key 11) Exception Handling 12) Difference Between Delete and Trunc 13) Procedure Overloading 14) Grant Revoke 15) Procedure Argument types. 16) Functions. 17) Joins
Differentiate between syntax and runtime errors.
Is oracle sql free?
Does execute immediate commit?
what is the syntax for using sql_variant_property? : Transact sql
Explain the significance of the & and && operators in pl sql.