Interview Questions

The diamond problem is an ambiguity that can occur when a class multiply inherits from two classes that both descend from a common super class

SQL is a structured query language while PL/SQL is an extension of SQL by introducing a procedural flow. PL/SQL has blocks of statements. PL/SQL works like other procedural languages and has concepts like control statements, sequential statements, exception handling etc.

As far PHP concern it only support single Inheritance in scripting. we can also use interface to achieve multiple inheritance.

You should not use AJAX if:

             =>  You want the page to show in a search engine, such as Google, because WebCrawler does not execute JavaScript code.

             =>  The browser does not support JavaScript.

             =>  You want to create a secure application.

Generally a business analyst covers several stages in Software Development Life Cycle.

Like:  Client Consulting, Client Requirement Study, Planning for business needs, Business Requirement Documenting, Work on functional requirement, Prepare test data with inputs from end users, Document use case scenarios, Help Testing team with test plan and testing, Help end users with user acceptance testing UAT, Go live and post production support tasks.

The flow chart gives a clear graphical representation of an implemented process. This makes the system simple to understand for all persons involved in the project. 

A collection just like an array is an ordered group of elements of the same type. Each elements position is determined by a unique subscript.

Index by tables:- They are similar to hash arrays that allows to search for subscript values using arbitrary numbers and strings.

They can be declared as:

TYPE type_name IS TABLE OF element_type [NOT NULL]

INDEX BY [BINARY_INTEGER | PLS_INTEGER | VARCHAR2(size_limit)];

INDEX BY key_type;

Example:

TYPE studenttyp IS TABLE OF emp%ROWTYPE

INDEX BY BINARY_INTEGER;

stud_tab studenttyp;

Nested tables:- they hold random number of elements and use sequential numbers as sub scripts.

They can be declared as:

TYPE type_name IS TABLE OF element_type [NOT NULL];

Example: TYPE employee_type IS TABLE OF NUMBER INDEX BY VARCHAR2(64);

Varrays: Holds a fixed number of elements which can be changed in run time. 

They can be declared as:

TYPE type_name IS {VARRAY | VARYING ARRAY} (size_limit) OF element_type [NOT NULL];

Example: TYPE Calendar IS VARRAY(366) OF DATE;

PL/SQL is Procedural Language SQL that is an extension of SQL that results in a more structural language composed of blocks. It is mainly used in writing applications that needs to be structured and has error handling.