问题
I've read that if you have a model that $actsAs = array('Tree'), that you can simply set the parent_id for your seed data, and a call to $this->Model->recover() should generate the proper lft and rght values for you, but when I do this, Cake seems to generate random values every time. The values vary from very large (in the thousands) to negative values. I've checked for circular references and found none as well. What could be wrong here?
SQL:
create table menus (
id int auto_increment not null,
parent_id int null ,
lft int null ,
rght int null ,
title varchar(1024) not null,
path varchar(1024) not null,
constraint pk_menus primary key (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
This is the seeded data: After one Model->recover()
+----+-----------+------+------+ +----+-----------+------+------+
| id | parent_id | lft | rght | | id | parent_id | lft | rght |
+----+-----------+------+------+ +----+-----------+------+------+
| 1 | NULL | NULL | NULL | | 1 | NULL | 595 | 619 |
| 7 | 1 | NULL | NULL | | 7 | 1 | 619 | 567 |
| 6 | 1 | NULL | NULL | | 6 | 1 | 627 | 595 |
| 5 | 1 | NULL | NULL | | 5 | 1 | 600 | 621 |
| 4 | 1 | NULL | NULL | | 4 | 1 | 603 | 621 |
| 3 | 1 | NULL | NULL | | 3 | 1 | 619 | 529 |
| 2 | 1 | NULL | NULL | | 2 | 1 | 595 | 529 |
| 8 | 2 | NULL | NULL | | 8 | 2 | 627 | 628 |
| 13 | 3 | NULL | NULL | | 13 | 3 | 595 | 567 |
| 12 | 3 | NULL | NULL | | 12 | 3 | 627 | 621 |
| 11 | 3 | NULL | NULL | | 11 | 3 | 595 | 631 |
| 10 | 3 | NULL | NULL | | 10 | 3 | 604 | 529 |
| 9 | 3 | NULL | NULL | | 9 | 3 | 595 | 567 |
| 14 | 5 | NULL | NULL | | 14 | 5 | 628 | 629 |
| 15 | 5 | NULL | NULL | | 15 | 5 | 567 | 529 |
| 16 | 5 | NULL | NULL | | 16 | 5 | 619 | 600 |
| 17 | 5 | NULL | NULL | | 17 | 5 | 627 | 605 |
| 21 | 6 | NULL | NULL | | 21 | 6 | 567 | 619 |
| 20 | 6 | NULL | NULL | | 20 | 6 | 595 | 567 |
| 19 | 6 | NULL | NULL | | 19 | 6 | 619 | 600 |
| 18 | 6 | NULL | NULL | | 18 | 6 | 567 | 529 |
| 22 | 10 | NULL | NULL | | 22 | 10 | 567 | 619 |
| 23 | 11 | NULL | NULL | | 23 | 11 | 64 | 621 |
| 24 | 12 | NULL | NULL | | 24 | 12 | 627 | 621 |
| 25 | 13 | NULL | NULL | | 25 | 13 | 605 | 595 |
| 32 | 16 | NULL | NULL | | 32 | 16 | 628 | 627 |
| 31 | 16 | NULL | NULL | | 31 | 16 | 567 | 619 |
| 30 | 16 | NULL | NULL | | 30 | 16 | 64 | 621 |
| 29 | 16 | NULL | NULL | | 29 | 16 | 567 | 619 |
| 28 | 16 | NULL | NULL | | 28 | 16 | 595 | 567 |
| 27 | 16 | NULL | NULL | | 27 | 16 | 627 | 621 |
| 26 | 16 | NULL | NULL | | 26 | 16 | 605 | 595 |
| 33 | 17 | NULL | NULL | | 33 | 17 | 567 | 619 |
| 37 | 19 | NULL | NULL | | 37 | 19 | 52 | 619 |
| 36 | 19 | NULL | NULL | | 36 | 19 | 52 | 619 |
| 35 | 19 | NULL | NULL | | 35 | 19 | 595 | 619 |
| 34 | 19 | NULL | NULL | | 34 | 19 | 63 | 621 |
| 38 | 20 | NULL | NULL | | 38 | 20 | 63 | 621 |
| 39 | 20 | NULL | NULL | | 39 | 20 | 63 | 621 |
| 40 | 21 | NULL | NULL | | 40 | 21 | 605 | 595 |
+----+-----------+------+------+ +----+-----------+------+------+
回答1:
I found that if I set the lft and rght values of the top level item to 1 and 2 respectively, recover() now generates the rest of the values properly. I find this to be a bug, but not a terrible one.
来源：https://stackoverflow.com/questions/8496084/how-do-i-generate-lft-and-rght-values-for-a-cakephp-2-0-tree