2 Questions?

homer09001

1) i already know a lot of php but not enough to build professional scripts which i want to be able to do, what books, websites other than this forum, would you recommend i read up on?

2) what difference is there between require() and include()?

Thanks for any replies.

sneakyimp

For starters, the PHP documentation is good for distinguishing [man]require[/man] and [man]include[/man]. It says right at the very top:

PHP Documentation wrote:
The documentation below also applies to require(). The two constructs are identical in every way except how they handle failure. They both produce a Warning, but require() results in a Fatal Error. In other words, use require() if you want a missing file to halt processing of the page. include() does not behave this way, the script will continue regardless. Be sure to have an appropriate include_path setting as well. Be warned that parse error in included file doesn't cause processing halting in PHP versions prior to PHP 4.3.5. Since this version, it does.

As for books and stuff like that, I've never read one. If I were you, I would find something you want to do and start figuring it out. If you get bogged down, post specific questions here to help you figure it out.

homer09001

As for books and stuff like that, I've never read one. If I were you, I would find something you want to do and start figuring it out. If you get bogged down, post specific questions here to help you figure it out.

see that what i have been doing now, but stuff like advanced querys etc and class's etc just aren't sticking in my head.

i can do querys but when you get to the point of using JOIN etc im lost?

dagon

sounds like you just need practice. Give it a few years :-)

sneakyimp

Try googling "understanding joins" for some good links. This one looks pretty good. The basic idea with a JOIN is that you are connecting tables together. There are different types. This info may not be 100% accurate but should be helpful.

INNER JOIN - Only show stuff in my results where the two tables match up exactly. Lots of queries have an implicit inner join in them like this:

SELECT t1.*, t2.* FROM table_1 AS t1, table_2 AS t2 WHERE t2.id=t1.id

LEFT JOIN - Get my everything in my 'left' table and then also fetch stuff from my 'right' table according to my join criteria...if there is no match in my right table for a given left record, then just fetch the left record and return NULL values for all those right table fields.

SELECT L.*, R.* FROM left L
LEFT JOIN right R
ON R.id=L.id

A right join is like a left join but you get everything in the 'right' table and any matching values in the LEFT table. If there's no matching record in the left table, use NULL values.

SELECT L.*, R.* FROM left L
RIGHT JOIN right R
ON R.id=L.id

An OUTER JOIN is almost never used as far as I know. It fetches some kind of enormous cross product of all the tables involved (only LEFT and RIGHT tables in the minimal case) and generally has a whole bunch of NULL values where this is no matchup. I have never used one of these in practice and can't really think of a good example.

homer09001

sneakyimp;10908555 wrote:
Try googling "understanding joins" for some good links. This one looks pretty good. The basic idea with a JOIN is that you are connecting tables together. There are different types. This info may not be 100% accurate but should be helpful.

INNER JOIN - Only show stuff in my results where the two tables match up exactly. Lots of queries have an implicit inner join in them like this:
SELECT t1.*, t2.* FROM table_1 AS t1, table_2 AS t2 WHERE t2.id=t1.id
LEFT JOIN - Get my everything in my 'left' table and then also fetch stuff from my 'right' table according to my join criteria...if there is no match in my right table for a given left record, then just fetch the left record and return NULL values for all those right table fields.
SELECT L.*, R.* FROM left L
LEFT JOIN right R
ON R.id=L.id 
A right join is like a left join but you get everything in the 'right' table and any matching values in the LEFT table. If there's no matching record in the left table, use NULL values.
SELECT L.*, R.* FROM left L
RIGHT JOIN right R
ON R.id=L.id 
An OUTER JOIN is almost never used as far as I know. It fetches some kind of enormous cross product of all the tables involved (only LEFT and RIGHT tables in the minimal case) and generally has a whole bunch of NULL values where this is no matchup. I have never used one of these in practice and can't really think of a good example.

see as much as you have done a good job of explaining it, i still don't understand the layout of the queries.

sneakyimp

Well maybe try SQL For Dummies then.