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!
Explain the concept of QBE?
Query-by-example represents a visual/graphical approach for accessing information in a database by the use of query templates called as skeleton tables. It is used through entering example values directly within a query template to represent what is to be achieved. QBE was developed at IBMs. T.J. Watson Research Centre and it is used through many database systems for personal computers. QBE is an extremely powerful facility that gives the user the capability to access the information a user needs without the knowledge of any programming language.
Queries in QBE are expressed through skeleton tables. QBE has two distinct features:
- QBE has two-dimensional syntax: Queries look like tables.- QBE queries are expressed "by example". Instead of giving a process for obtaining the desired answer, the user provides an example of what is desired.An example of QBE is given asEMPNO NAME SALARY DESIG DEPTNO P..x "Manager"
This query tells the system to such as for tuples in EMP relation which have designation Manager. For each such tuple, the system assigns the value of the Ename attribute to the variable x and prints it.
What are temporary tables? Temporary tables exist solely for a particular session or whose data persists for the duration of the transaction.
What is inheritance? Define it in detail? Inheritance Inheritance can be at the levels of types, or at the level of tables we first consider inheritance of types, then i
Explain the term High level DML? High level DML A high-level or non-procedural DML permit the user to specify what data is needed without specifying how it is to be acquired.
Analyzing Association Traversal Association Traversal shall be understood properly for the association design explanation. Analyzing association traversal means analyzing tra
Differance between internal and external schema? Internal and external schema: Internal Schema • Describes the physical storage structure • Uses a physical data model External
assume we have the following apllicationthat model sccer team the games they play and the players inv each teamin the design we want to capture
What are the functions of an accumulator? The accumulator is the register associated with the ALU operations and sometimes I/O operations. It is an integral part of ALU. It hol
Define upgrade and downgrade? It gives a mechanism for conversion from shared lock to exclusive lock is called as upgrade. It gives a mechanism for conversion from exclusive
What are the categories of SQL command? SQL commands are separated in to the following categories: 1. Data - Definitition Language 2. Data Manipulation language 3. Dat
Database Administrator One of the main perpose for having the database management system is to have control of both data or programs accessing that data. The person having li
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