1 (2)

, , SQL , XML

. -

2/40

. E/ , , , XML, UML, ODL.

. SQL, XPath, XQuery, ,

Datalog.

.

23/40

, First Course in Database Systems/3rd Edition. . 2 .

.

4/40

SQL?

:SELECT bFROM RWHERE a=10;

SELECT bFROM R;

??NULL - .

a b5 2010 3020 40

R

35/40

?

SELECT aFROM R, SWHERE R.b = S.b;

SELECT aFROM RWHERE b IN (SELECT b FROM S);

6/40

, : , , , .

, , . Web . (Data mining). . .

47/40

...

, (Web - www). Google . (Queries) Amazon, eBay, .

8/40

...

(concurrency-control). () .

.

59/40

?

1. .:

= ; = /.

2. .3. .

10/40

!

name manfWinterbrew PetesBud Lite Anheuser-Busch

Beers

( )

()

611/40

= . : . : Beers(name, manf) Beers(name:

string, manf: string)

= . = .

12/40

?

. .

, SQL, .

713/40

Beers(name, manf)Bars(name, addr, license)Drinkers(name, addr, phone)Likes(drinker, beer)Sells(bar, beer, price)Frequents(drinker, bar)

= ( ). .

14/40

SQL

SQL , , (query language), , .

, SQL data-definition ( ) .

815/40

()

:CREATE TABLE (

);

:DROP TABLE ;

16/40

: . :

INT or INTEGER () - . REAL or FLOAT () - . . CHAR(n ) = n - .

VARCHAR(n ) = n .

917/40

:

CREATE TABLE Sells (bar CHAR(20),beer VARCHAR(20),price REAL

);

18/40

SQL

(Integers) (reals) .

, (single quotes). a = , ., Joes Bar.

NULL.

10

19/40

(DATE) (TIME) SQL.

:DATE yyyy-mm-dd

: DATE 2007-09-30 30-, 2007.

20/40

:TIME - hh:mm:ss

( ). : TIME - 15:30:02.5 = 3 30 .

. ( 1, , )

11

21/40

-

(PRIMARY KEY) UNIQUE.

.

.

22/40

PRIMARY KEY UNIQUE .

:CREATE TABLE Beers (

name CHAR(20) UNIQUE,manf CHAR(20)

);

12

23/40

CREATE TABLE .

. .

24/40

:

Sells ():

CREATE TABLE Sells (bar CHAR(20),beer VARCHAR(20),price REAL,PRIMARY KEY (bar, beer)

);

13

25/40

PRIMARY KEY UNIQUE

1. PRIMARY KEY, UNIQUE .

2. PRIMARY KEY NULL . , UNIQUE NULL , NULL.

26/40

, .

: .

: () .

14

27/40

= . ( ). -

( ).

- : . .

28/40

:

Bud

A.B.

Gold1995

MapleJoes

Mlob

beer beerbar

manfmanf

servedAt

name

namename

addr

prize

year award

- root

The bar objectfor Joes Bar

The beer objectfor Bud

15

29/40

XML

XML = Extensible Markup Language. HTML () (., italic), XML (., -this is an address).

: (. ), () XML .

30/40

XML

(declaration), .

:

(root tag) .

16

31/40

, HTML, , . .

.

XML / .

32/40

: XML

Joes BarBud

2.50Miller

3.00

NAME

BEER

17

33/40

HTML, XML =(atttribute = value) .

( ).

34/40

Bar,

Beer

name price

18

35/40

DTD ( )

.

:)>. . . . . .

]>

36/40

: DTD

]>

BAR BAR

BAR - NAME BEER.

BEER NAME PRICE.NAME PRICE

HTML

19

37/40

XML (attributes).

DTD,

() E, .

38/40

:

manf CDATA #IMPLIED>

Required = ;Implied =

:

20

39/40

!

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