Multi layer architecture


SQL
	Table vs database
	create table
		schema
		not null
		primary key
	types
		decimal(5,2)
		date and time types
		enum
		blob
	update tablename set columnname = value where ...
	delete from tablename where ...
	select columnname from tablename where .. order by columname limit 3
	alter table ...
	drop tablename
	describe table tablename
	joins
	nested queries (and in vs =)
	min and max count and average and group by
	insert into tablename values ( ...)
	database decomposition
		might cost speed
		reduces redundency and possibility of inconsistency


	
PHP
	Error supression with @
	isset($varname)
	empty($varname)	
	Error checking with die
	Arrays
		Not really arrays
		indexed by key, which can be string
		not always the same type
		foreach ($array as $item)
		foreach($array as %key => $item)
	Cookies
		session cookies
		deleting cookies
		size and number limits
		what if cookies are turned off
	Functions
		default arguments
	Objects
		__construct
		__tostring
		$this->thing
		$this->method() vs method()
		class vs local vs global variables
	print_r
	header("location: ...")	
	Variables
		global
		superglobal
			$_REQUEST
			$_COOKIE
			$_POST
			$_GET
	Databases
		Know some way to fetch data like
			mysqli_query
			mysqli_num_rows
			mysqli_fetch_row
		mysqli_connect
		mysqli_select_db
		Error checking

Login
	Pick random number
	Verify random number
	passwords always encrypted!
	Know this is vulnurable to snoop attack

Advertising
	pay cost per click vs cost per impression
	conversion rate matters
	can buy keywords, liited by region, OS, platform, etc.
	can buy site ads

Pagerank
	links are votes
	more important pages get more votes
	there are blackhat and whitehat search engine optimization techniques
	there are contests

/robots.txt