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A functional dependency occurs between two attributes in a database, A and B, if there exists a relationship such that for each value of A there is only one corresponding value of B (A -> B). This can be extended to a functional dependency where A may be a set of tuples (x, y, z) that correspond to a single value B ([x, y, z] -> B). In simple mathematical terms the functional dependency must pass the vertical line test for proper functions. Normalization of a relational database means that the relations (tables) in the database conform to a set of rules for a certain normal form (First - Sixth Normal Form [1-6NF] and/or Boyce-Codd Normal Form [BCNF]). The higher the normal form of a table the less vulnerable it is to data inconsistency and data anomalies formed during updates, inserts, and deletes. Normalization often reduces data redundancy in a database which reduces data inconsistency and anomaly risks. Normalizing a database requires analysis of the closure of the set of functional dependencies to ensure that the set complies with the rules for the given normal form. If the table does not comply with the rules then the table is split following specific procedures to achieve the desired normal form. Every table in a database has a normal form and to make a statement that a database is in a certain normal form (ex. 3NF) means that every table complies with the rules for 3NF.
What else can I help you with?
Fully functional dependency?
A functional dependency X --> Y is full functional dependency if removal of any attribute 'k' from X means that the dependency does not hold any more.Full functional dependency is minimal in size (contain non-redundant data)In a relation R , attribute B of R is fully functionallydependent on an attribute or set of attributes A of R , if B is functionally dependent on A, but not functionally dependent on any proper subset of A.ORAàB is a fully functionally dependency, if removal of any attribute X from A would result into the cancellation of dependency. i.e. (A-{X})-->B does not hold.
What is important to consider when creating a database?
Memory should be taken into account when building a database and maintain integrity and avoid redundancy through normalization.
What is the purpose of using joins in database is normalization the only purpose of it?
The purpose of using Normalization is to avoid the data redundancy in tables. The normalized schema is much faster in performance so you can get a quick response from the database. OLTP database designers follow the Normalization rules but the tables in Data warehousing(OLAP) data bases are in the De normalized form, they won't follow the Normalization technique. For this reason we are using more complex queries in Data warehouses which uses more system resources. Some one might explain you better way......... Thanks Blueberry
What are the key concepts covered in the Fundamentals of Database Systems 7th Edition?
The key concepts covered in the Fundamentals of Database Systems 7th Edition include database design, normalization, SQL queries, transaction management, indexing, and data warehousing.
Is the process of creating table designs by assigning specific fields or attributes to each table in a database?
Normalization is the process of creating table designs by assigning specific fields or attributes to each table in a database.
Find out functional dependencies?
A constraint between two sets of attributes is known as functional dependency in relational database. Determination of functional dependencies is vital in database denormalization, normalization and relational model.
Describe database normalization?
Database Normalization is the process of organizing the fields and tables of a relational database to minimize redundancy and dependency
What is normalization and objective of normalization?
Normalization is the process of organizing data in a database to reduce redundancy and dependency. The objective of normalization is to minimize data redundancy, ensure data integrity, and improve database efficiency by structuring data in a logical and organized manner.
What is data dependency in DBMS?
Data dependency in DBMS refers to the relationship between different data elements within a database. There are three main types: functional dependency (one attribute determines another), partial dependency (part of a composite key determines other attributes), and transitive dependency (dependency between non-key attributes). Understanding data dependencies is crucial for database normalization and maintaining data integrity.
Describe the dependency diagram and explain its purpose?
A dependency diagram is a visual representation of a dependency graph. Dependency diagrams are integral to software development, outlining the complex, interrelationships of various functional elements. Typically in a dependency diagram, arrows point from each module to other modules which they are dependent upon.The dependency diagram is used as an aid to normalization within database design.
How functional dependency is related to database table design?
The functional dependency is related to the database table design through the foreign and primary keys. The foreign and primary keys are functionally dependent on each other.
Difference between partial dependency and fully functional dependency?
The difference is that partial dependency is when a database's attribute is only partially dependent on the primary key. Fully functional dependency is when the attribute is entirely dependent on the key.
What do you understand by Normalization?
Normalization is the process of organizing data in a database to reduce redundancy and dependency by dividing larger tables into smaller ones and defining relationships between them. It ensures data integrity and avoids anomalies like update, insert, or delete anomalies. Normalization is essential for efficient database design and maintenance.
What is the purposed normalization in database?
The purpose of normalization is to reduce the chances for anomalies to occur in a database. The Normalization also forces you to use a database in a Object orientated manner. (This is good of course.)
Is The process of normalization is reversable?
Yes, the process of normalization is reversible. Normalization is a database design technique that organizes data in a relational database to reduce redundancy and improve data integrity. You can always revert the normalization process by denormalizing the database if needed.
Why normalisation necessary during database design?
Database normalization, or data normalization, is a technique to organize the contents of the tables for transactional databases and data warehouses. Normalization is part of successful database design; without normalization, database systems can be inaccurate, slow, and inefficient, and they might not produce the data you expect.
What is non trivial functional dependency?
-->non trivial functional dependency is totally opposite to the trivial functional dependency. --> non trivial dependency means X-->Y that is if Y is not proper subset of X table or relation with X then it said to be non trivial functional dependency.
