Multiple Access to Database

Dear List - I have a database: mysql> show tables; +---------------------+ | Tables_in_hospital2 | +---------------------+

| Intake3             |
| Visit3              |

+---------------------+ mysql> describe Intake3; +--------+-------------+------+-----+---------+-------+

| Field  | Type        | Null | Key | Default | Extra |

+--------+-------------+------+-----+---------+-------+

| Site   | varchar(6)  | NO   | PRI |         |       |
| MedRec | int(6)      | NO   | PRI | NULL    |       |
| Fname  | varchar(15) | YES  |     | NULL    |       |
| Lname  | varchar(30) | YES  |     | NULL    |       |
| Phone  | varchar(30) | YES  |     | NULL    |       |
| Height | int(4)      | YES  |     | NULL    |       |
| Sex    | char(7)     | YES  |     | NULL    |       |
| Hx     | text        | YES  |     | NULL    |       |

+--------+-------------+------+-----+---------+-------+ mysql> describe Visit3; +--------+--------------+------+-----+---------+----------------+

| Field  | Type         | Null | Key | Default | Extra          |

+--------+--------------+------+-----+---------+----------------+

| Indx   | int(4)       | NO   | PRI | NULL    | auto_increment |
| Site   | varchar(6)   | YES  |     | NULL    |                |
| MedRec | int(6)       | YES  |     | NULL    |                |
| Notes  | text         | YES  |     | NULL    |                |
| Weight | int(4)       | YES  |     | NULL    |                |
| BMI    | decimal(3,1) | YES  |     | NULL    |                |
| Date   | date         | YES  |     | NULL    |                |

+--------+--------------+------+-----+---------+----------------+ I want Bob to have access to all tables and fields, with all privileges. I want John to have read access to Visit3: fields [Site, MedRec, Weight, BMI] 1] How do I do it? 2] In the case that I have two users with write access to a table, how do I lock the tables/fields so that the two users can not change the same varible at the same time? Thanks. Ethan