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A key is a set of attributes that uniquely identifies an entire tuple, a function dependency allow us to express constraints that uniquely identify the values of certain attribute.
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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 is Transitive functional dependency?
A functional dependency X->Y is transitive in R, if there exists an attribute Z in R, such that X-> Z, Z-> Y .
What is Partial functional dependency?
Partial Functional Dependency Indicates that if A and B are attributes of a table , B is partially dependent on A if there is some attribute that can be removed from A and yet the dependency still holds. Say for Ex, consider the following functional dependency that exists in the Tbl_Staff table: StaffID,Name -------> BranchID BranchID is functionally dependent on a subset of A (StaffID,Name), namely StaffID. Source :http://www.mahipalreddy.com/dbdesign/dbqa.htm
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.
Diffentiate between full and partial dependency?
Full Dependency:Given a relation R and functional dependency x->y (y is fully functionally dependent on x)there is no any z->y ,where Z is a proper subset of xPartial Dependency:If any proper subset of the key determine any of the non-key attributes then there exist a partial dependency p q->c d (p q is the primary key)p->cq->cp->dq->d
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.
How many types of functional dependencies in DBMS?
In DBMS there is three type of functional dependency1 FULL FUNCTION DEPENDENCY.2 PARTIALLY FUNCTION DEPENDENCY.3 TRACIENT FUNCTION DEPENDENCY.Functional Dependency can be classified as follows:Full Functional dependency Indicates that if A and B are attributes(columns)of a table, B is fully functionally dependent on A if B is functionally dependent on A ,but not on any proper subset of A.Partial Functional Dependency Indicates that if Aand B are attributes of a table , B is partially dependent on A if there is some attribute that can be removed from A and yet the dependency still holds.Transitive Functional Dependency: A condition where A , B and C are attributes of a table such that if A is functionally dependent on B and Bis functionally dependent on C then C is Transitively dependent on A via BFor Detailed explanation with example visit Authors original Postinghttp://www.mahipalreddy.com/dbdesign/dbqa.htm
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.
What is functional dependency in oracle?
In Oracle, functional dependency is when the value of one thing is completely determined by another thing. Functional dependency happens when one attribute determines another attribute in a relation.
Examples of functional dependency in dbms?
a functionaly dependency is an association between two relational attribute of same relational database.one of the attribute is known as determinant and the other one is determined.for the each value of determinant there is only one value associated of determined. graphicaly it can be represented A----->B .
Describe the purpose of normalizing data and also list out the dependencies involved in the process of normalization?
The purpose of normalizing data in DBMS is to reduce the data redundancy and increase the consistency of data. a) Partial dependency: non-prime attribute ( field) depends on other non-prime attributes b) Functional dependency c) Transitive dependency
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 is Trivial and Non Trivial Dependency?
Trivial functional dependencyA trivial functional dependency is a functional dependency of an attribute on a superset of itself. {Employee ID, Employee Address} → {Employee Address} is trivial, as is {Employee Address} → {Employee Address}.
Ppt for functional dependacies in DBMS?
YES
What is Transitive functional dependency?
A functional dependency X->Y is transitive in R, if there exists an attribute Z in R, such that X-> Z, Z-> Y .
What is difference between Partial Functional Dependency and Full Functional Dependency?
A functional dependency is defined as a constraint between two sets of attributes in a relation from a database.Given a relation R, a set of attributes X in R is said to functionally determine another attribute Y, also in R, (written X→ Y) if and only if eachX value is associated with at most oneY value.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.Partial Functional Dependency Indicates that if A and B are attributes of a table, B is partially dependent on A if there is some attribute that can be removed from A and yet the dependency still holds.A key is a set of attributes that uniquely identifies an entire tuple, a function dependency allow us to express constraints that uniquely identify the values of certain attribute.
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.
