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.
Question: (a) Prepare an ERD for the scenario given below. (b) Convert the ER diagram produced in (a) above into its physical design. You have to choose an appropriate Pri
Create role named role_table that allows a user to create tables. Using role_table allow users kripa and reena to create tables. CREATE ROLE role_table; GRANT CREATE ANY TABLE
Prepare a data flow diagram for computing the volume and surface area of a cylinder. Inputs are the height and radius of the cylinder. Outputs are the volume and surface area of th
External failure : A failure can also result because of an external cause, such as earthquakes, fire, floods, etc. The database must be duly backed up to avoid troubles occurring d
Entities Let us first be aware of the question: What are entities? An entity is an object of concern used to show the things in the actual world, e.g., table, car, bo
How is the database organised in Oracle? Database organized within Oracle in terms of table and table holds attributes and values. A database consists of one or more logical
How many levels can be viewed in Architecture of the database ? Architecture of the database can be viewed as three levels.
Give Concurrent sub states diagram for the classroom and exam held. In Figure, simultaneous substrates have been taken. After passing Minor 1 test you could give Minor 2 test. T
explain exhaustively the problems associated with ER diagrams. include illustrations in your answer
Let consider the given partial relation EMP. Let us make some sub-queries for them EMPNO ENAME JOB SAL DEPTNO 7566
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