PHP Functions and keywords

associative array An array that uses text indexes; an associative array would be used as follows: $arrSomeArray[‘elementName’]

client-side scripting Script code that runs on the client machine (as opposed to the server machine). A common example of this is JavaScript code, which is executed by a user’s browser.

server-side scripting Scripting that is executed on the server before anything is sent to the client.

constructor A function that is called automatically upon a new instantiation of a class.

cookie A small piece of information that can be stored on a client machine by a program on the server if the browser allows it.

database A collection of data held in a specific place and usually accessed through a database server, such as MySQL.

global The main scope in a PHP script; all variables not contained in functions and classes.

here-doc A string-quoting style that allows for clearly readable multiline strings; most closely related to doubled quoting in PHP.

HTTP The protocol used by Web servers and browsers to request and transfer files.

inheritance The automatic gaining of a parent class’s member variables and functions.

JavaScript A scripting language unrelated to Java (with the exception of a few syntactical and structural similarities); almost always executed client-side.

object-oriented programming language A programming language, such as C++, Java, or PHP, that makes use of abstract data types (classes).

Object-Oriented Programming (OOP) Programming in an OO (objectoriented) language, which enables the programmer to model real-world concepts with classes and thus break problems down into smaller, independent or interdependent parts.

open source software Software to which the source code is freely available.

pattern matching The act of matching a regular expression against a string.

parent class The class from which a subclass was derived.

recursion The calling of a function from itself. The result is similar to a loop, but less efficient and generally more confusing.

reference An alias to a variable.

row A single record or entry in a MySQL table.

column A set of all the same fields from every row in a table.

regular expression A collection of special wildcard characters used to search strings for only partially known string patterns.

string A collection of one or more letters; a string can be a word, a sentence, or just a single letter.

subclass A class created by extending a parent class using the extends keyword.

type casting The act of forcing a variable to become a given type.

true The opposite of false. Can also be represented by any non-zero number, non-null value, or non-empty string.

unary operator An operator that only takes one argument. Example: the negative sign in –21 is a unary operator.

whitespace Any character that doesn’t print a visible character on the screen; whitespace characters include new lines (\n), spaces, tabs, and so on.