PHP is simple to use, besides being a structured programming language, like C, Perl or from version 5 upwards even Java, the syntax of language being a combination of the three.
Due to its modularity, it can also be used to develop standalone applications, for example in combination with PHP-GTK, or can be used as Perl or Python on the command line.
Perhaps one of the most important features of the language is working with most relational databases, from MySQL to Oracle, through MS SQL Server, PostgreSQL, or DB2.
PHP can run on most operating systems, from UNIX, Windows, or Mac OS X, and can interact with most web servers. Your PHP code is interpreted by the WEB server and generates an HTML code that will be seen by the user (to the browser being sent only HTML code).
The LAMP architecture has become popular in the web industry as a fast, free, and integrated application development. Along with Linux, Apache, and MySQL, PHP is the letter P, although sometimes it refers to Python or Perl. Linux acts as an operating system for all other applications, MySQL manages databases, Apache acts as a web server, and PHP acts as an interpreter and communicator between them.
PHP uses extensions specific to its files: .php, .php3, .ph3, .php4, .inc, .phtml. These files are interpreted by the web server and the result is sent in the form of text or HTML code to the client’s browser.
Internal Data Types:
1. Boolean – true or false logical values similar to C ++ or Perl.
2. Integer – integer numbers (in base 10, 2 or 16). The maximum value depends on the system and the type of integer. The type may be “signed” or “unsigned,” meaning dependent on the + or – sign, or independently of them. Values for integer unsigned are greater than for signed. 32-bit systems can create integer numbers between -2147483648 and 2147483647 (2 ^ 31-1). The maximum for 64-bit systems is 9223372036854775807.
3. Float – known as real numbers. The maximum values are also platform-dependent, generally with a maximum of ~ 1.8e308 with an accuracy of 14 decimals after the comma (64-bit IEEE format).
4. Strings. Before PHP6, a character was equivalent to one byte. There are no limitations on the length of a string outside the PHP memory.
5. Array – in PHP an array is a data type that contains a group of elements. Each element has an internal index in the group, and each index corresponds to the value of the element itself. Such a group can be used as a simulation for various mathematical situations such as vectors, series, element dictionaries, ordered lists, matrices, or matrix matrices. The indices and values of a group can be any type of internal PHP (except objects, resources, and null which can’t be indexed).
6. Objects – A class is a collection of properties and functions with common logic. Objects are instances of a class, in which the properties of the object are given specific values.
7. Resources – these are special variables that link to external PHP resources. For example, connection to a database is an open resource and maintained with the help of functions specifically defined for this work.
8. NULL – is a special data type that means that the variable has not been defined and that it has no value or value is unknown.