Define null values, Database Management System

Assignment Help:

Define null values.

In some cases a certain entity may not have an applicable value for an attribute or if we do not know the value of an attribute for a certain entity. In these cases null value is used.

 


Related Discussions:- Define null values

Data Analysis, A buyer for a large department store chain must place orders...

A buyer for a large department store chain must place orders with an athletic shoe manufacturer six months prior to the time the shoes will be sold in the department stores. In par

How relational calculus is different from relational algebra, How Relationa...

How Relational Calculus is different from Relational Algebra? What do understand by TRC queries and DRC queries?  Ans: Relational calculus contain two calculi, the tuple relati

Read-set(t) and timestamps-optimistic concurrency contents, read-set(T) : E...

read-set(T) : Each data items that are read by a transaction T Timestamps : for all transaction T, the start-time and the end time are reserved for all the three phases.

Illustrate the deployment diagram, Illustrate the Deployment Diagram A...

Illustrate the Deployment Diagram A deployment diagram shows all nodes on network, their processor execution and interconnections. In a dynamic model, this is used to represen

Data management, Develop a database broker framework to implement a persist...

Develop a database broker framework to implement a persistence mechanism for the domain objects involved in the use case dealt with in Question 2.  a. Specify the attribute type

Write a qbe query to display names of cs department, Consider a table stude...

Consider a table student (std_id, std_name, date_of_birth, percent_marks, dept_name). Write a QBE query to display names of Computer Science department students who have scored mo

What are stand-alone procedures, What are stand-alone procedures? Proce...

What are stand-alone procedures? Procedures that are not part of a package are called as stand-alone because they independently defined. A good example of a stand-alone procedu

What is boyce-code normal form, Boyce-Code Normal Form (BCNF) A relatio...

Boyce-Code Normal Form (BCNF) A relationship is said to be in BCNF if it is already in 3NF and the left hand side of each dependency is a candidate key. A relation who is in 3N

What is aggregate function, What is aggregate function? Briefly describe it...

What is aggregate function? Briefly describe it? Aggregate functions are functions that take a collection of values as input and return a one value. SQL offers 5 built-in aggre

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