Technology Questions

Syntax:

SORT   file-1 ON ASCENDING/DESCENDING KEY key....

USING  file-2

GIVING file-3.

USING can be substituted by INPUT PROCEDURE IS para-1 THRU para-2

GIVING can be substituted by OUTPUT PROCEDURE IS para-1 THRU para-2.

file-1 is the sort workfile and must be described using SD entry in FILE SECTION.

file-2 is the input file for the SORT and must be described using an FD entry in FILE SECTION and SELECT clause in FILE CONTROL.

file-3 is the outfile from the SORT and must be described using an FD entry in FILE SECTION and SELECT clause in FILE CONTROL.

file-1, file-2 & file-3 should not be opened explicitly.

INPUT PROCEDURE is executed before the sort and records must be RELEASEd to the sort work file from the input procedure.

OUTPUT PROCEDURE is executed after all records have been sorted. Records from the sort work file must be RETURNed one at a time to the output procedure.

UNION selects only distinct values whereas UNION ALL selects all values and not just distinct ones

While allocating KSDS Datasets, free space is declared at regular intervals at the time of initial loading. This is done because this free space is utilized for keeping the data arranged in sequence physically, even though inserted randomly.

CONSTRUCTOR : PHP allows developers to declare constructor methods for classes. Classes which have a constructor method call this method on each newly-created object, so it is suitable for any initialization that the object may need before it is used.

DESTRUCTORS : PHP 5 introduces a destructor concept similar to that of other object-oriented languages, such as C++. The destructor method will be called as soon as all references to a particular object are removed or when the object is explicitly destroyed or in any order in shutdown sequence.

An SQL statement is a string of characters that conforms to the syntax and format specified in the international standard.

A query is a statement that returns a record-set.

1)Divide by zero        – This is raised when any number is attempted to divide by zero.

2)TOO MANY ROWS   - A SELECT INTO statement returns more than one row.

3)CASE_NOT_FOUND - No choice in the WHEN clause of a case statement is selected.

4)LOGIN_DENIED      - An attempt to login with an invalid username or password.

5)PROGRAM_ERROR  - An internal PL/SQL problem.

It is necessary to understand some of the concepts used extensively in object oriented programming.These include

Objects
Classes
Data abstraction and encapsulation
Inheritance
Polymorphism
Dynamic Binding
Message passing

When an object is passed by value, this means that a copy of the object is passed. Thus, even if changes are made to that object, it doesn’t affect the original value. 

When an object is passed by reference, this means that the actual object is not passed, rather a reference of the object is passed. Thus, any changes made by the external method, are also reflected in all places.