Technology Questions

Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc.

Communication means the meaning full exchange of information between two communication media

Joins are used to combine data of one or more tables. Joins should be used when there is abundant data. Joins can be LEFT, RIGHT, OUTER, INNER or even SELF JOIN. The purpose is to bind data from multiple tables without any receptivity

In an Interactive Report, user can define maximum 20 secondary lists.

Oracle database comprises of three kinds of files:
- Datafiles
- Redo log files
- Control files

An abstract class can have instance methods that implement a default behavior. An Interface can only declare constants and instance methods, but cannot implement default behavior and all methods are implicitly abstract. An interface has all public members and no implementation. An abstract class is a class which may have the usual flavors of class members (private, protected, etc.), but has some abstract methods.

Oracle NOT NULL is used on a column to ensure that the value for that column can never be NULL.
Example:
Below, the constraint is that the id should never be NULL. If it is, oracle throws an error.
create table employee ( id number NOT NULL, Name varchar(200) );

Anonymous class is class without name.

EX:

class A {

}

class Demo {

    A r = new A() {

        }; //anonymous class

}

A NSArray’s contents can not be modified once it’s been created whereas a NSMutableArray can be modified as needed, i.e items can be added/removed from it.