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

Create table to evaluating websites-reasoning, Have a look around the site,...

Have a look around the site, and at some of the sites they have featured. These are all examples of bad design, and also offer an explanation about why they fall into this category

Backward recovery (undo), Backward Recovery (UNDO): In this system the unco...

Backward Recovery (UNDO): In this system the uncommitted changes made by a transaction to a database are undone.  Instead the system is reset to the last consistent state of databa

In e-r diagram how derived attribute are represented, In E-R Diagram how de...

In E-R Diagram how derived attribute are represented ? In E-R Diagram By Dashed ellipse derived attribute are represented.

Cube building in dataware housing , 1) Define a job scheduling strategy tha...

1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict

What is called a query evaluation plan, What is called a query evaluation p...

What is called a query evaluation plan? A sequence of primitive operations that can be used to assess a query is a query evaluation plan or a query implementation plan.

Creating views with read only option-data control, Creating views with Read...

Creating views with Read only option : In the view definition this option is used to make sure that no DML operations can be done on the view.

Create a view containing name and number of department, Create a view emp_d...

Create a view emp_dep containing e_name and number of dependents from the tables employee and dependent of (i) CREATE VIEW emp_dept AS SELECT ename, COUNT(*) FROM employee, dep

Subclassing, In the ER diagram, one example of subclassing is depicted foll...

In the ER diagram, one example of subclassing is depicted following the Services entity. The subclasses Item Based and Time Based are created. The entity Services gains the attribu

Explain dml with some examples, Explain DML with some examples? DML - D...

Explain DML with some examples? DML - Data Manipulation Language: statements used for managing data within schema objects. Some examples: • SELECT - retrieve data from the a da

Query to list the employee name have 10000 salary, Consider employee table ...

Consider employee table of (i) and list names of department(s) for which average salary for department is more than 10,000. (SELECT d_name FROM dept WHERE d_code IN (SELECT d_c

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