Basic PHP functions for connecting to database using PDO

db-functions.php

<?php

/*
-- ===================================================================================================
-- Author:          Sergio Camba (https://github.com/scamba)
-- Create date:     17/04/2017
-- Update date:     15/07/2017
-- Description:     Function library for connection to database using PDO and compatible
                    with a multitude of databases such as MySQL, PostgreSQL, SQLite, Cubrid, ODBC,
                    MS SQL Server, Oracle, Firebird / Interbase, DB2, 4D, IBM and Informix.
-- Warning:	    To work properly, the PDO driver connection must be enabled on server, 
		    +info: https://secure.php.net/manual/en/pdo.installation.php
-- ===================================================================================================

------------------------------
--> Explanation of functions:
------------------------------


*	startConection($type, $host, $dbname, $user, $pass)
--------------------------------------------------------->

Description:
	- Create a PDO object connection.

Params: 
	- $type:	(string) Database type (mysql, postgre, etc).
	- $host:	(string) IP or host (usually localhost).
	- $dbname:	(string) Database name.
	- $user:	(string) Database user name.
	- $pass:	(string) Database user password.

Returns:
	- A PDO object connection.



*	SQLToArray($conn, $query)
------------------------------->

Description:
	- Get a SQL Select query, and returns an array with results.

Params:
	- $conn:	Object connection (created previously with startConnection).
	- $query:	SQL query type SELECT.

Returns:
	- An array with results from SQL Select query.



*	SQLExecute($conn, $query)
------------------------------->

Description:
	- Get a SQL query and execute it.

Params:
	- $conn:	Object connection (created previously with startConnection).
	- $query:	SQL query of any type, just execute it (essentially designed for INSERT, UPDATE, etc...).

Returns:
	- true/false depending on whether the SQL statement is executed correctly or not.



*	SQLToField($conn, $query)
------------------------------->

Description:
	- Get an SQL statement, execute and return a single data.

Params:
	- $conn:	Object connection (created previously with startConnection).
	- $query:	SQL statement type SELECT.

Returns:
	- Single data from SQL statement.



*	 closeConnection()
------------------------>

Description:
	- Close connection created with startConnection(...).

No get params.

Returns:
	- Directly a null, which will be assigned to the connection variable created with startConnection(...).



*/

function startConnection($type, $host, $dbname, $user, $pass)
{
	return new PDO( $type. ':host=' .$host. ';dbname=' .$dbname. ';charset=utf8', $user, $pass);
}

function SQLToArray($conn, $query)
{
	$aux = $conn->query($query);
	return $aux->fetchAll();
}

function SQLExecute($conn, $query)
{
	$aux = $conn->prepare($query);
	return $aux->execute();
}

function SQLToField($conn, $query)
{
	$aux = $conn->query($query);
	return $aux->fetchColumn();
}

function closeConnection()
{
	return null;
}

?>