车的表有个cid字段....，人的表有个uid字段....，中间表有uid和cid字段，同个uid有多个cid。人表uid | name 1 | A 2 | B 3 | C车表cid | name 1 | a 2 | b 3 | c 4 | d 5 | e中间表id | uid | cid 1 | 1 | 1 //a车属于A 2 | 1 | 2 //b车属于A 3 | 2 | 4 //d车属于B 4 | 3 | 3 //c车属于C 5 | 3 | 5 //e车属于C