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!
Eliminate Repeating Groups
The problem is, "Find out the list of employees, who knows DB2".
For this problem we require to perform an awkward scan of the list looking for references to DB2. This is ineffective and a very untidy way to retrieve information.
We change the relation to 1NF. Please note that in the Department-loc fields and conversion Department will be part of Employee relation. The Emp-ID in the Database relation matches the primary key in the employee relation, giving a foreign key for relating the two relations with a join operation. Now we can response the question by looking in the database relation for "DB2" and getting the list of Employees. Please note that in this design we require not add D-ID (Database ID). Just the name of the database would have been sufficient as the names of databases are original.
Employee Relation
Database Relation
Emp-ID
Emp-Name
D-ID
Database-name
1
Gurpreet Malhotra
2
Access
Faisal Khan
4
DB2
3
Manisha Kukreja
FoxPro
Sameer Singh
Oracle
What is horizontal fragmentation? Horizontal fragmentation divides the relation by assuming every tuple of r to one or more fragments
List any two significant differences between a file processing system and a DBMS. File Processing System vs. DBMS Data Independence - Data independence is the capacity t
Creation of Indexes Automatically: When a primary key or Unique constraint is show in a table definition then a unique index is formed automatically. Manually: User can
What is substitutability? Any method of a class-say A can equally well be adjured with any object belonging to any subclasses B of A. This characteristic leads to code reuse, a
distributed quey processing
Write short notes on extension and intension? In any data model, it is significant to distinguish among the description of the database and the database itself the description
Suppose R is a relation with attributes A1, A2,..., An. As a function of n, tell how many superkeys R has, if: 1.1 The only key is A1. 1.2 The only key is A1 and A2. 1.3 The o
How to Insert data in your table from another table? insert into e.g, To insert tuples from employee into N_emp created above, use following statement Insert into N_emp
1. Staff(staffID, firstName, lastName, availabilityID, experience, phone, mobile, email); 2. Availability(availabilityID, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday,
What are ways of finding out either an update is required or not for derived attributes? The ways to find out an update is required or, not are as: Explicit update
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