What is null described testing for null in sql?, Database Management System

Assignment Help:

What is NULL? Give an example to described testing for NULL in SQL?

The NULL SQL keyword is used to represent either a missing value or a value which is not applicable in a relational table. Consider there is a relation:

Person(id, name, address, phone)
Now to search ids and names of person who do not have a phone is:
Select id, name
from Person
where phone is null

Related Discussions:- What is null described testing for null in sql?

Sources of utilities for a dbms, There are three main sources of utilities ...

There are three main sources of utilities and applications for a DBMS: a. Vendor applications and utilities are given for working with or maintaining the database, and generally

Define cardinality and participation constraints, Define cardinality and pa...

Define cardinality and participation constraints on a relationship type, completeness constraint on generalization. Ans: Cardinality defines the number of entities to wh

Mr.dattu, Define a job scheduling strategy that will meet business requirem...

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 pictori

What is the error handling, What is the error handling Traditionally, b...

What is the error handling Traditionally, bits have been sent over line lacking any error correcting scheme in physical layer. The presence of the CPU in each modem makes it po

Referential integrity, It can be easily defined as: The database must no...

It can be easily defined as: The database must not have any unmatched foreign key values. The term "unmatched foreign key value" means a foreign key value for which there doe

Er database theoretical and modeling database system, Need an expert in ER ...

Need an expert in ER database theoretical and modeling database system Project Description: Need an expert in ER database theoretical and modeling database systems? Skills

Database, why are older data models are being replaced by new data models

why are older data models are being replaced by new data models

What is cardinality ratio, What is Cardinality Ratio? Cardinality Rati...

What is Cardinality Ratio? Cardinality Ratios - The cardinality ratios for relationship kinds specifies the maximum number of relationship instances in which an entity can pa

Sql select employee from table with at least one department, Consider emplo...

Consider employee (e_no, e_name, e_salary, d_code), dept (d_code, d_name) and dependent (depndt_name, e_no, relation). Show the names of employees in purchase and accounts departm

Describe the four main ways of optimising disk block access, Describe the f...

Describe the four main ways of optimising disk block access. Ans: a. Disk b. Non-volatile writes buffers c. File organization (Clustering) d. Log-based file system

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages