Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Define entity integrity and referential integrity. How does SQL allow specification of these?
Ans: Entity Integrity Rule- If the attribute A of relation R is a prime attribute of R after that A cannot accept null values.
Referential Integrity Rule- In referential integrity, it is made sure that a value that appears in one relation for a given set of attributes as well appears for a particular set of attributes in another relation.
In SQL, referential integrity and entity integrity rules are implemented as constraints on the relation known as reference Key constraint and primary Key constraint correspondingly.
These constraints can be fixed with relation at the time of creation of the relations or after the creation of the relations by altering the definition of the relations. For instance:
What is called remapping of bad sectors? If the controller detects that a sector is injured when the disk is initially formatted, or when an attempt is made to write the secto
Explain the concepts of relational data model? Relational Data Model - The relational model was first introduced through Prof. E.F. Codd of the IBM Research in the year 1970
Describe queries with complex types? The present extension of the SQL query language deal with the complex type Let us start with the simple example: Find the title and t
Data Control The data control mostly refers to commands that permit system and data privileges to be passed to several users. These commands are usually available to database admi
What is the State Machine Engine The straightest approach to implement control is to have any way of explicitly representing and executing state machines. With the help of thi
difference between MIS and DSS
What are the three classes of SQL expression? SQL expression consists of three clauses: Select From Where
Rearrange Classes and Operations Sometimes, the similar operation is defined across different classes and can easily be inherited from a familiar ancestor, but more often oper
What are the basic objects of the data dictionary? Tables Domains Data elements Structures Foreign Keys
What is magnetic disks?explain it? Magnetic disk provides the bulk of secondary storage of modern computer system. The disk capacity is growing at over 50% per year. But the st
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd