(). . , , .
, .
, . , ,[1] , 50 .
.
:
-
-
.
, (. conventional database): ( ) .
.
(. in-memory database, memory-resident database, main memory database): .
(. tertiary database): ( ), .
, ; .
:
.
]
, (. centralized database): , .
(. distributed database): , - .
(. heterogeneous distributed database):
(. homogeneous distributed database): .
, (. partitioned database): (, ), .
(. replicated database): ().
(. spatial database): , . .
, (. temporal database): , - , , .
|
|
|
- (. spatial-temporal database) : , , .
(. round-robin database): , , .
(), .
́ ́ ́ ́ () , [1].
( );
;
, ;
( , ).
:
, , ,
, , , - ,
, ,
( ), .
:
-
-
( )
( ).
-
- -. ( ). . . . : ; ; , . , ; .
- .
: Microsoft Access, Paradox, dBase, FoxPro, Visual FoxPro.
-
- , . - . - . : ; ; , .
|
|
|
: Oracle, Firebird, Interbase, IBM DB2, Informix, MS SQL Server, Sybase Adaptive Server Enterprise, PostgreSQL, MySQL, Caché, .
, , . . . SQL .
: OpenEdge, SQLite, BerkeleyDB, Firebird Embedded, Microsoft SQL Server Compact, .
. -. , . . . .
. , , . . ANSI (American National Standards Institute) . : , .
1. , . . , . , , , , , .
2. . , , , . , , . , , , . . .
3. , , . . ( ) . , .
: . , , . , . . . ( 1 2) ( 2 3) .
|
|
|
, , .
, .
, :
1. - , . :
o ,
o , , ,
o
, . "-".
2. - . - . .
3. - , ..
. .
() , .
, , :
;
, , .
. , . .
( 0): , .
. :
1. . , . , .
2. . , . .
3. . .
4. . , , .
|
|
|
5. . , - . , , .
6. . , - - , .
7. . , . , .
8. . 2 : . , , , ( , ) , . , , , .
9. . , , , .
10. . .
11. . , , .
12. . , , , .
[]
1.
2. . , , .
3. . , . - . , , .
4. -
. , . .
. . , , . , , , .
. , , , . "" , , , . , . , , . , , , . , , .
|
|
|
3 .
-, , , " ". " " , - , , .
SQL2 , , UNKNOWN. :
.
: , , , .
() :
.
.
.
.
- . -.
, , .
, : , ( ), (, ).
, , , , ; .
, . , , 10 000 . , , 10 000.
, , , , , , , , , . , : , , : , .
. , , .
. - , .
- , , , . , : .
. . , .
.
, .
, - (, ).
- .
:
- . , . , , , , - . , , , ;
- . - , . ;
- , . , , , , .
, - . (, ). ( ) . , .
, . , , .
6. . : .
́ (. transaction) , , . , , . , .
(), . (, two-phase commit ). , , -, .
ACID . , , . : , (timeout) . . .
( , IBM DB2), ACID. . , :
(write ahead logging, WAL)
(shadow paging)[2].
, , . , , .
, Sybase MS SQL Server 2005, , . . , . . , [3]
. (timestamp-based concurrency control) MVCC. , . , Oracle 7. , , . , , ( ). , , . :
1.
2. ,
3. ,
(, ) . , :
, . , , .
, , .
, . .
Firebird , , MVCC, . MS SQL 2005. , , .
