Technology Questions

An index is a object which is used to improve performance during retrieval of records.

CREATE [UNIQUE] INDEX index_name 

ON employee[emp_id, emp_name,dept_id]

[COMPUTE STATISTICS]

The UNIQUE keyword is used when combined values of the index should be unique.

The COMPUTE STATISTICS during the creation of index optimizes the plan of execution of the SQL statement and improves performance.

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.

Inheritance is the ability to create new classes based on existing classes. It is useful to reuse existing code.

PHP: Hypertext Preprocessor is open source server-side scripting language that is widely used for web development. PHP scripts are executed on the server. PHP allows writing dynamically generated web pages efficiently and quickly. The syntax is mostly borrowed from C, Java and perl. PHP is free to download and use.

The function setcookie() is used to define a cookie that is to be sent along with HTTP headers. The cookie must be sent prior to any output from the script as is the protocol restriction. After setting the cookies, they can be used when the next page is loaded by using $_COOKIE or $HTTP_COOKIE_VARS arrays.

TDD is an acronym for Test-Driven Development. TDD is a software development process that relies on the repetition of a very short development cycle: first the developer writes an (initially failing) automated test case that defines a desired improvement or new function, then produces the minimum amount of code to pass that test.

TDD is an iterative software development process where you first write the test with the idea that it must fail.

This is a different approach to the traditional development where you write the application functionality first andthen write test cases. The major benefit of this approach is that the code becomes thoroughly unit tested (you canuse JUnit or other unit testing frameworks).

Primary key : a relational database constraint. Primary key consists of one or more columns that uniquely identify a row in the table. For a normalized relation, there is one designated primary key.

Unique index: a physical object that stores only unique values. There can be one or more unique indexes on a table.