 (superkey)
| (candidate key)
| (primary key)
|
 (secondary key)
| (foreign key)
|
| 2
| 3
| 4
|
| 5
| 6
|
, ...
|
|
| ,
|
|
| ,
|
|
:
|
|
|
|
|
|
|
|
|
|
: 2015-05-06; !; : 584 |
:
:
| 1529 - 