create table nodes (
	node_id int not null auto_increment,
	is_directory boolean default false,
	relative_path varchar(500) not null,
	type varchar(20) not null default 'data',
	name varchar(100) not null default 'no name',
	note varchar(200) not null default "",
	code varchar(100) not null default "error",
	primary key (node_id)
);

/*base user information*/
create table users (
	user_id int not null auto_increment,
	username varchar(50) not null unique,
	password varchar(255) not null,
	email varchar(50),
	home_directory int not null,
	primary key (user_id),
	foreign key (home_directory) references nodes(node_id)
);

create table node_access (
	node_id int not null,
	user_id int not null,

	can_view boolean not null default true,
	can_edit boolean not null default false,
	check (can_view=true or can_edit=true) ,
	foreign key (node_id) references nodes(node_id),
	foreign key (user_id) references users(user_id)
);

create table node_links (
	directory_id int not null,
	node_id int not null,
	check (directory_id != node_id), 
	foreign key (directory_id) references nodes(node_id),
	foreign key (node_id) references nodes(node_id)
);