.
1. .
2. .
3.
4. .
5. .
6.
. ' , .
ϳ (18391914) (1841 1902), . ϳ , , . . 1970 ' , , (Codd E. F., "A relational model for large shared data banks", Comm. ACM, 13:6, pp. 377387). , .
. 
. , ' . ' .
' . 2.1.
2.1.
| ', ( ) | |||
| , ' | |||
| ³ | ' , ( ) | ||
| () | |||
| ҳ | ҳ ' , ( ) | ||
| ( ) | |||
| ( ) | |||
| () ' , | |||
| , () ( ) | |||
| , ' . , ( ). , , () | |||
| () | ʳ | ||
| ʳ ( ) | |||
| ³, , ', | |||
| , ' ' , ; , , ' | |||
| ' | ' | ||
| ' "--" | ' ' . ' , . | ||
| ' "--" | ' "--" , . ' , | ||
| ' "-- " | ' . . , ' ' ' "--", ' | ||
, :
|
|
|
□ ;
□ ;
□ .
' (), , , (, RESTRICT, JOIN ..).
