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Material Type: Notes; Class: Database Systems I; Subject: Computer Science; University: University of California-Santa Cruz; Term: Unknown 2003;
Typology: Study notes
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Winter 2003 1
Today’s Lecture
(structured and semistructured data)
University of Pennsylvania (by Peter Buneman and Susan Davidson)
P art I : B ack g roun d
What’s the difference between documents and databases? 80% of the world’s data does NOT reside in a database!
Winter 2003 3
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Winter 2003 4
D ocum en ts v s D atab ases
Document world
plenty of small documents usually static
implicit structure section, paragraph, toc,
tagging
human friendly
content form/layout, annotation
Paradigms “Save as”, wysiwyg meta-data
author name, date, subject
Database world
fewer large databases usually dynamic
explicit structure (schema)
records
machine friendly
content schema, data, methods
Paradigms Atomicity, Concurrency, Isolation, Durability
meta-data schema description
Winter 2003 7
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sttu v w x&yjz {Z|j}<~ < xª|j < |< .2 ]0w x&yjz {|]} wgV<M< 1<}M|M ]|.j0 z}MC<x;z <}Mx# M .&¡ ²M²M«<¡ «j¢0«<)¦ yM|]0© ¶0¤ &¡ M M¥<¡ <M¥< M<³)jxª{; ] ] 0xM <¨ ¹ºyM V» ¼¼Z§ §§2 jx&{& . ] 0xM <¨¼& 0
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Winter 2003 8
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Winter 2003 9
S w issp rot ( con t’d) 'òñ;ó ñô.õö [÷Qöø (^) [ù÷#ú*÷Zú b úûû a ú<[ Q)ü bý (^) û _Vü7Q (^) [1ûV÷ ö1þ'òñ;ó ñúõiõö (^) ÷[øùû.ÿ b (^) ûü (^) ûb (^) ùîú õiõö (^) ÷[$÷Zú 'Q _ Q (^) úûa!Q)ôböμb (^) ÷a÷àb1ö1aêb'ibúV÷ê(^) ùb÷öÖa (^) ûü÷û a$ô.ü'Q b úV÷ öýû _üûõü (^) úQüàbö1a ÷ö ûa i^ b ' a÷Zú õ.ô (^) ÷aû iQ)öa2þ 'òñ;ó ñú÷ ÷0bü (^) ÷[ ø[QèQ (^) [2ù1û ü (^) úPú ûûa új[ Q)ü bý (^) û _ü'Q (^) [1ûV÷ öú ^ý<Q iõ (^) ÷öúc&þ a1ü (^) û i ý ñ#þ a1ü _÷üú!1ô "μVõ iþ a1ü ü'Q (^) ú÷[1û (^) ú!#$ (^) ú%'ú ûû a%új[ Qü bý (^) û$ þ " (^) úûû a ú<[ Qü bý (^) û ü Q[1û ÷öúV÷ ý2ö7b .þ ô[ úV÷ ýö'b & ' ô[ ùb÷ö () (^) ú ý$<Q iõ* (^) ÷ö iû<[ b úõiõö÷[þ ô[ùb÷ö + ýb , bî(^) ùb÷öî^b (^) ÷a÷'c;þ ô[ùb÷ö -) aû[bî(^) ùb÷öî^ ibúV÷'c;þ ô[ )Qa (^) %üûVú . _ üü'Q (^) ÷aQö (^) û bü iQÿ ÷àb(^) ÷a2þ ô[ a÷#ú õ*]ô (^) ÷a/0 1 (^) ÷ö[1û ü' (^) ùb÷ö$^ý b , b ñZa (^) û[bc ^ª Q (^) [û ö[÷ b<c&þ ô[ 'Qö1ô (^) ÷[ 2 (^) ú ñ (^43) û ^÷ö$ü (^) ûô þ! Vc&þ ô[ 'Qö1ô (^) ÷[ . (^) û ñ (^43) ú ^÷ö$ü (^) ûô þ! Vc&þ ú 5ðú û5 õûöû )b'b6# #7 "8$a^ #! #Va1a*^ ûü'^ bü (^) úVú jô (^) [ô 0b (^) ô÷öý1 (^) ú5 ÷#û55 ú _" (^) û ô 5 ýúû " 5 5ù ü 5 ú _ü bü ûö]ü b 5 a2 (^) ü übûbûb÷ô[1û9 "!a 5 a1ö1a (^) ûô 5 bý (^) ö ÷üù[$÷ ü7_ ý._.ýèô (^) úö7b_ (^) ÷ô b 5 ýôjý (^) ÷üý÷b ÷_.ý1b^ ûj[ 5 [ a]üü^ ú5 ú bý^ ú bô 'a^5 )ù*5 ÷ü!_Vô ü^ ûýa^ 0^ ' _jbý^ úù ": ^ ö$ü7ý^5 ú a÷ þþþ
Winter 2003 10
II. XML Basics and Document Type
Descr iptor s
Winter 2003 13
XML s tr u c tu r e
Nesting tags can be used to express various structures.
E.g. A tuple (record) :
Winter 2003 14
XML s tr u c tu r e ( c o n t. )
tag repeatedly:
Winter 2003 15
T er m in o lo g y
The segment of an XML document between an opening and a corresponding closing tag is called an element.
element
element, a s u b -element no t a n element o f
Winter 2003 16
XML i s tr ee-l i k e
per s o n
n a m e tel tel em a il
M a lc o lm A tc his o n ( 2 1 5 ) 8 9 8 4 3 2 1
( 2 1 5 ) 8 9 8 4 3 2 1 m p@ d cs .gla. a c .s c
S emi s tr u c tu r ed d a ta mo d els ty p ic a lly p u t th e la b els o n th e ed g es
Winter 2003 19
T w o w a y s o f r ep r es en ti n g a D B pr o jec ts : title b u d get m a n a ged By
em plo y ees : n a m e ss n a ge
Winter 2003 20
Project and Employee relations in XML
hi jk h Olmonprq's t0k htAu t4v qkxwy!totoqm4z m>q'sn {zu t4u nz|h}0t4u tAv qk hOj~'i{q!t k |h }j~'i{q!t0k hO:yz y'{q'i kZ n qh}:yz'y'{q!i ! k h}lmonprq's t0k hqXlv n'!q'q k hOz y:q k n q|h }z y:q k h z kW' h}0 z k hy'{q k'Zh}y'{qk h}qXlv n'!q'q k
hqXlv n'!q'q k hOz y:q k yz im>y h}z'y:q k h z k '' h}0 z k hy'{q k h}y'{q k h}qXlv n'!q'q k hOlmonprq's t0k htAu t4v qk ~!trn{ ~u iq'i'qu sv q h}0tAu t4v qk hOj~'i{q!t k h}j~'i{q!t0k hO:yz y'{q'i k yz imoy h}:yz'y'{q'i ! k h}lmonprq's t0k h}i jk
P r o jec ts a nd emp lo y ees a r e i nter mi x ed
Winter 2003 21
hi jk h Olm>npoq'sto'k hOlmonprq's t k ht4u tAv qkxwy!t>trqm4z6moq'sn {zu tAu nzh}0tAu t4v qk hOj~ i{q!t0k h}j~'i{q!t k hO:yz'y'{q'i ! kZ n qh}8yz'y'{q'i!k h}lmonprq's t0k hOlmonprq's t k ht4u tAv qkZ~!ton6{~u iq'i!qu sv q'Xh}0t4u tAv qk hOj~ i{q!t0k h}j~'i{q!t k hO:yz'y'{q'i ! kW yz'i moyh }8yz'y'{q!i k h}lmonprq's t0k h}lmonprq's tr'k
Project and Employee relations in XML (cont’d)
hqXlv n'!q'q''k hqXlv n'!q'q k h,z y:q k nqh }z'y:q k h z kW! h}0 z k hy'{q k!Zh }y'{qk h}qXlv n!!q'q k hqXlv n'!q'q k h,z y:q kW yz im>yh }z'y:q k h z k ''Zh}0 z k hy'{q kh }y'{q k h}qXl*v n!!q'q k hqXlv n'!q'q''k h}i jk
E mp lo y ees f o llo w p r o jec ts
Winter 2003 22
hi jk h Olmonprq's trk htAu t4v qkxwy!totoqm4z m>q'sn {zu t4u nz|h}0t4u tAv qk hOj~'i{q!t k |h }j~'i{q!t0k hO:yz y'{q'i kZ n qh}:yz'y'{q!i ! k htAu t4v qkZ~!trn{ ~u iq'i'qu sv q'Xh}0tAu t4v qk hOj~'i{q!t k |h }j~'i{q!t0k hO:yz y'{q'i kW yz imoyh }:yz'y'{q'i ! k h}lmonprq's tr'k
Project and Employee relations in XML (cont’d)
hqXlv n'!q'q''k hOz y:q k n q h}z y:q k h z k ' h}0 z k hy'{q k ' h}y'{q k hOz y:q k yz im>y h}z'y:q k h z k '' h}0 z k hy'{q k * h}y'{q k h}qXlv n'!q'q''k h}i jk
O r w ith o u t “ s ep a r a to r ” ta g s …
Winter 2003 25
W h en to u s e a ttr i b u tes
It’s not always clear when to use attributes
; M9JGT]EL T*T L] ,¸ ,¹º¢9¬§\»,¼,¦O =
; L$I\NPMB= ·,?
cNPI$LO±¾`O T$?rC$IHJ JI7? I?T* ;BF'M\NPIH< K>= ?A?A?
;BF $MHJGT ]ELH=
;8TTL$]^= ¸\¹¢9¬¿§O»¼O¦ ;BF TT L$]g= ; L$I\NPMB= ·,?
cNPI$LO±¾`O T$?rC$IHJ JI7? I?T* ;BF'M\NPIH< K>= ?A?A? ;BF $MHJGT ]ELH=
Winter 2003 26
U s in g I D s
ÀEÁAÂ$ÃZÄ ÅÆ,Ç À^ÈÉ$ÊAËÌÍÎÄ ÏOÐgÑAÒÂ$Í É$ÑÓÃÌ ÔÕ ÉÊ ÐgÑÃÂ$ÊrÆ ÑgÁAÂÔÕÉ$ÊÐgÑrÒÌÕ$ÍÑ!Ç À^Í Â$ÃÉ,Ç¿Ö!ÂÍ ÉW×\Ì$ÉPÀ\Ø'Í Â$ÃÉ,Ç À\Ø'ÈÉ$ÊAËÌÍ,Ç À^ÈÉ$ÊAËÌÍÄ ÏOÐgÑrÒÌÕÍÑgÙÕ$Ä ÅÏÊÉÍ,ÐgÑrÒÂ$Í É Ò ÙÚ Ñ!Ç À^Í Â$ÃÉ,Ç¿ÖÌÕ$Í×\ÌÉPÀ\Ø'Í Â$ÃÉ,ÇÛÀ^ÃÌ ÔÕ É$ÊÜØÇ À\Ø'ÈÉ$ÊAËÌÍ,Ç À^ÈÉ$ÊAËÌÍÄ ÏOÐgÑÃÂÊrÆ Ñ^ÙÕ$Ä ÅÏÊAÉ$ÍÐgÑ4ÒÂ$Í É¡ÒG ÙÚ Ñ!Ç À^Í Â$ÃÉ,ǨÝ:Â$ÊrÆW×\Ì$ÉPÀ\Ø'Í Â$ÃÉ,Ç À\Ø'ÈÉ$ÊAËÌÍ,Ç À^ÈÉ$ÊAËÌÍÎÄ Ï\ÐgÑ4Ò ÙÚ ÑÛÃÌ ÔÕ É$ÊÐgÞÃÂ$ÊoÆ ÑgÁAÂÔÕ É$Ê ÐgÑrÒÌÕ$Í$Ñ!Ç À^Í Â$ÃÉ,Ç¿Ö!ÂÙ*Ú|×9ÌÉPÀ\Ø'Í ÂÃÉ,Ç À\Ø'ÈÉ$ÊAËÌÍ,Ç À\ØÁAÂ$ÃÄ ÅÆ,Ç
Winter 2003 27
ODL schema
ßà á,ââ Ý:Ì ãÄ É äæåç$èå9é$è (^) Ý:Ì ãÄ ÉËêBë åì (^) ÔÄ ÔÅ Éîí ï á è èð ñ^ òOóèå^ ËÔÊ Ä ÍôÔ Ä ÔÅ É$õ áè0èðñ^ òOóèå^ ËÔÊGÄ ÍôÏÄ ÊAÉ ÙÔGÌÊ õ ðå (^) àáè!ñ öEé (^) â÷ ñø ËÉÔÀHù\ÙÔGÌÊ Ç¾Ù ËÔ Ë ñéúåHð (^) âå ù\ÙÔGÌÊû û ÙÔGÉ Ïü,ý Í$õ áè0èðñ^ òOóèå^ ÄÍÔ¥þÿ Ïô$ÉÔõ õ
ßà á,ââ ù\ÙÔGÌÊ äæåç$èå9é$è (^) ù\ÙÔGÌÊËêEë å$ì (^) ÍÂ$ÃÉ í ï á è èð ñ^ òOóèå^ ËÔÊ Ä ÍôÍÂÃÉ$õ ðå (^) àáè!ñ öEé (^) â÷ ñø ËÉÔÀ:Ý¥Ì ãÄ É,Ç ÂÙÔGÉ Ïü,ý Í ñéúåHð (^) âå Ý:Ì ã$Ä ÉOûGûÜÙ'Â Ë Ô Ë'õ áè0èðñ^ òOóèå^ ÄÍÔB ôÉ$õ áè0èðñ^ òOóèå^ ËÉ*ÔÀBË ÔÊ Ä Íô\DzÏÄ ÊAÉ ÙÔGÉÏõ õ
Winter 2003 28
A n ex amp l e
!#"$% &('#)+-, &+./ 0 1+23 4 506875 0 9$;:< 5&++=?> > >. 0 @+23 4 506 23"+= A6BDC6ED3"F"(G<H./23"+= I 5J+'5 6KML(LN@LL(L.MJ+5' / .3 PO 8, 04"+' 5&5Q++"01 6./ 0 1+23 4 5068RD 5TS 5Q(&.D 0 4+2< 1 D0I 23"+= A6BDC6ED3"(OT"+UT"O K./23"+= / 5J+'5 6K(MLN@LL(L.MJ+5' / .3 VG5 8WH ( D&+"&(23./ 0 1+23 4 5068,"+'D "0YX 0 1 9Z+. 0 423 4 506 23"+= A6BDC6ED3"F"+[5<H./23"+= I 5J+'5 6ULN@L(LL.35J+5'( 6 .3 \
"+2< 4 D0 3"< &(" 8," ( -7( ].3&(" "+2< 9+^>& AIB5C6E %VVG a([5b ."+23 4+%^*>_& ."+2< 4 D0I "+2< 4 D0 3"(O< c&(" cd(+"(&TS 5&&(0e].3&+"F "+23 4+^*>_& AIBDC/E VO Uf< .<"23 4+^*>& "+'5g([."+' ."+2< 4 D0I "+2< 4 D0 3"+G5< &+" c>9"&h("&5&+&.3&(" "+2< 4+%^>& A6BDC6E PGi(< ." 2 < 4+ ^>& ."+2< 4 D0I
.
Winter 2003 31
S p eci f y in g t he st r u ct u r e
The structure of a person entry can be specified by
name, greet?, ad d r* , ( tel | fax ) * , emai l *
This is known as a regular expression. Why is it important?
Winter 2003 32
R eg u lar E x p r essi o n s
Each regular expression determines a corresponding finite state automaton. Let’s start with a simpler example:
name, ad d r* , emai l
This suggests a simple parsing program
name
ad d r
emai l
Winter 2003 33
A n o t her ex amp l e
name,ad d res s * ,( tel | fax ) * ,emai l *
name
ad d res s
tel
tel
fax
fax
emai l
emai l
Adding in the optional greet f u r ther complicates things
Winter 2003 34
A DTD for the address book
< !D O C T Y P E ad d res s b o o k [ < !E L E M E N T ad d res s b o o k (p ro jec t * )> < !E L E M E N T p ro jec t (n ame, g reet? , ad d res s * , (fax | tel) * , email* ) > < !E L E M E N T n ame (# P C D A T A )> < !E L E M E N T g reet (# P C D A T A )> < !E L E M E N T ad d res s (# P C D A T A )> < !E L E M E N T tel (# P C D A T A )> < !E L E M E N T fax (# P C D A T A )> < !E L E M E N T email (# P C D A T A )> ]>
Winter 2003 37
R ec u rsi v e DTDs
Fc ; ®¥Y8¨ ¦H c¥c¯ - Y8s88 °¥ H¨¦H c¥cx 8/(K¨ ¢c 5¡ - Y8s88 ±HI(K¨x ¨¦ §c Y¦c²3©K£ ³ 8IK¨ ´<´§³H 8IK¨μ ¡ ´<´ ²/¦³H
« « « ¶¡
What is the problem with this?
Winter 2003 38
R ec u rsi v e DTDs c on t’ d.
Fc ; ®¥Y8¨ ¦H c¥c¯ - Y8s88 °¥ H¨¦H c¥cx 8/(K¨ ¢c 5¡ - Y8s88 ±HI(K¨x ¨¦ §c Y¦c²3©K£ ³ 8IK¨ ·D ´<´§³H 8IK¨ ·¸ 5¡ ´<´V²6¦ ³H
« « « ¶¡
What is now the problem with this?
Winter 2003 39
Some things are hard to specify
Each Y element is to contain ¨ ¦ § , ¦ ¥ and *¨ elements in some order.
- YYY8 °Y ` ¨¦Y§c¦¥ c;5¨ ¹¬K<¦ ¥cc;5¨V¨¦Y§c ¹¬ 35¨V¨¦Y§;¦ ¥Yc ¹¬ (^) « « « 5¡
Suppose there were many more fields!
Winter 2003 40
S u m m ary of X M L reg u lar ex p ressi on s
