Define transitive dependencies, Database Management System

Assignment Help:

What do you understand by transitive dependencies? Define with an example any two problems that can take place in the database if transitive dependencies are available in the database.

 Ans:  Assume X, Y, and Z are the set of attributes. If X → Y and Y → Z afterwards the functional dependency X → Z is a transitive functional dependency. Alternatively, if a nonkey attribute is as well functionally dependent on the other nonkey attribute(s), then there is a transitive functional dependency. Transitive functional dependencies are as well cause the data redundancies and the other consequences. For instance, consider the subsequent relation:

CREATE TABLE CONTACTS

(CONTACT_ID NUMBER (5) PRIMARY KEY,

 L_NAME   VARCHAR (20),

 F_NAME   VARCHAR (20),

 COMPANY_NAME VARCHAR (20),

 COMPANY_LOCATION VARCHAR (50))

 In the following relation, all the nonkey attributes are functionally dependent on the primary key, that is CONTACT_ID. But, there is as well a transitive functional dependency exists in the relation - CONTACT_ID  COMPANY_LOCATION because CONTACT_ID → COMPANY_NAME and COMPANY_NAME →COMPANY_LOCATION.  The result of transitive dependency, there are anomalies in the above relation like this:

  • Insertion Anomaly - A new company cannot be inserted till a contact person has been assigned to that company.
  • Deletion Anomaly - If a company has just only one contact person and is deleted from the table, we will lose the information about that company, as the company information is related with that person.
  • Update Anomaly - If a company changes its location we will should make the changes in all the records in which the company name appears.

Related Discussions:- Define transitive dependencies

Write query to select student from math department, Consider the table stud...

Consider the table student and list names of students in the departments other than maths and computer. SELECT std_name FRM student WHERE dept_name NOT IN (‘Maths','Computer);

The second normal form (2nf), The Second Normal Form (2NF) Definition: ...

The Second Normal Form (2NF) Definition: A relation is in 2NF if it is in 1NF and each non-key attribute is fully dependent on each candidate key of the relation. Some of th

Eliminate repeating groups, Eliminate Repeating Groups The problem is, ...

Eliminate Repeating Groups The problem is, "Find out the list of employees, who knows DB2". For this problem we require to perform an awkward scan of the list looking for re

File organization, what is file organization? what are file organization te...

what is file organization? what are file organization techniques.explain in detail? explain random file organization technique, multikey file organization technique?what is indexin

What is a view, What is a view? How it is related to data independence? ...

What is a view? How it is related to data independence? A view might be thought of as a virtual table, that is, a table that does not really exist in its own right but is inste

Write query to list the staff who work within the branch, Consider the foll...

Consider the following relations: BRANCH( bno, street, area, city, pcode, Tel_no, Fax_no) STAFF( Sno, Fname, Lname, address, position , salary, bno) Express the subsequent qu

System level permissions-data control, System level permissions : With the ...

System level permissions : With the use of data dictionary you can view them.       Let us take the table name as user_sys_privs (used in oracle).       DESCRIBE USER_SYS_PRI

What was the method in which records are physically stored, What was the me...

What was the method in which records are physically stored in a specified order according to a key field in each record ? A method in which records are physically stored within

Function module, When a function module is activated syntax checking is per...

When a function module is activated syntax checking is performed automatically. YEs, a function module is activated syntax checking.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd