Creating a custom function

nawrik

I've just discovered the potential of PHP functions and i'm currently struggling how to get my head around creating a custom function.

I want the function to access a MySQL database, SELECT all of the rows (I guess putting into an array?) and output into specific variables.

Example:

function extractSettings ()
{
*list all settings in the table.
*loop through and assign unique variables.
*make those variables available outside of the function.
}

The idea is to use this function to call the details from the database (rather than SELECT " FROM etc...) everytime.

I'm sure this is possible, but should you CONNECT to the db in the function?

I can visualise what I want, I just can't create it!

All help appreciated. An example would be excellent.

Thanks in advance.

rincewind456

Regarding the connection to a db I tend to write it once as a separate file then use [man]require_once()[/man] as I need it.

You could do a function to build a query, a simple one like this works

function extractSettings($table, $fields='*', $wherefield='', $wherecondition=''){

$sql = 'SELECT ';

foreach ($fields as $key=>$value) {
$sql .=	'`'.$value.'`,';
}
$sql =rtrim($sql,',');

$sql .= 'FROM `'.$table.'`';

if ($wherecondition !=false) {
	$sql .= ' WHERE `'.$wherefield.'` = '.$wherecondition.';';
}

return $sql;
}

#usage
$fields = array('field1','field2','field3');
echo extractSettings('table', $fields, 'field3', 7);

But unless you're going to be writing the same basic query all the time you'll be better of writing it new each time.

nawrik

Thanks for the swift reply rincewind456.

After studying what you just wrote, I think I may have realised a vital flaw in my plan...

The idea of using the function was to create an easy to use way for me to select and create variables of ALL of the data in a table.

However, this is ultimately wrong because the function will need an argument:

extractSettings('table', $fields, 'field3', 7);

This will of course take just one specified piece of data, not ALL.

Is there a way to create variables from all db data 'en-mass'...

I imagine a way to call this script and then after it has run I will have access to the variables of all data elements.

Any ideas?

MODS, this maybe should be in the 'Newbs' category - i'm punching above my weight!

rincewind456

That function with no arguments, other than the table name, would provide a sql query of

SELECT * FROM `table`;

you could hard code the table name if you wanted but it defeats the point somewhat by restricting it in that way.

As for a function that returns all the data to an array, then there is a built in one [man]mysql_query()[/man] so there's not a lot of point in reinventing the wheel.

djjjozsi

its not a good idea to get all rows from a query. build a function, which can indentify pager variables to get these rows in blocks.