Why Don’t Scientists Use
Databases?
Peter Buneman
Division of Informatics
University of Edinburgh
Digital Libraries grant IIS 98-17444
(NSF,DARPA,NLM, LoC,NEH, NASA)
http://db.cis.upenn.edu
http://db.cis.upenn.edu/Research/provenance.html
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
1
Why Don’t Scientists Use
Relational Databases Much?
Thanks to:
• The ontologists and astronomers at Edinburgh
• The database and bio-informatics groups at Penn
• Aleri Inc.
Special thanks (material stolen from)
• Sanjeev Khanna, Wang-Chiew, Keishi Tajima,
Susan Davidson, Fidel Salas
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
2
Scientific Data is Ubiquitous
• 500 or so public molecular biology databases.
– much discovery in silico
• Vast amounts of satellite imagery
– maintaining it is very expensive
• Terabytes of astronomical data (not image data)
• Linguistic corpora are essential research tools -also in terabytes
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
3
Relational DBs -- tabular data
Id
123
456
321
Name
H. Simpson
L. Simpson
A. Jones
Address
Title
Springfield
Algorithms
Springfield
Voltaire
London
Geometry
Id
Course
Grade
456
Geometry
A
123
Algorithms
D
456
Voltaire
A
321
Geometry
B
321
Algorithms
C
Dept
CompSci
French
Math
Teacher
Dr. Deadhead
Prof. lePew
Dr. Obtuse
•Useful information is obtained by combining tables.
•Efficient algorithms for
– comining and indexing tables
– transaction processing (updates and multiple users)
• Relational databases are a multi giga-$ industry
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
4
Reasons for Mismatch
• Scientific data sets are too large
(image data, huge analyses)
• Scientific data is too complex
• Relational databases don’t work well
with arrays and scientific computation
• Schema evolution and history are
important
• Databases are too expensive
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
5
Metadata
Swissprot -a curated
database
...
OS
OC
OC
RN
RP
RC
RX
RA
RL
...
ID
AC
DT
DT
DT
DE
OS
OC
OC
RN
RP
RC
RX
RA
RL
RN
RP
RA
RL
CC
CC
CC
CC
CC
DR
DR
DR
KW
FT
FT
FT
FT
FT
FT
FT
FT
SQ
11SB_CUCMA
STANDARD;
PRT;
480 AA.
P13744;
01-JAN-1990 (REL. 13, CREATED)
01-JAN-1990 (REL. 13, LAST SEQUENCE UPDATE)
01-NOV-1990 (REL. 16, LAST ANNOTATION UPDATE)
11S GLOBULIN BETA SUBUNIT PRECURSOR.
CUCURBITA MAXIMA (PUMPKIN) (WINTER SQUASH).
EUKARYOTA; PLANTA; EMBRYOPHYTA; ANGIOSPERMAE; DICOTYLEDONEAE;
VIOLALES; CUCURBITACEAE.
[1]
SEQUENCE FROM N.A.
STRAIN=CV. KUROKAWA AMAKURI NANKIN;
MEDLINE; 88166744.
HAYASHI M., MORI H., NISHIMURA M., AKAZAWA T., HARA-NISHIMURA I.;
EUR. J. BIOCHEM. 172:627-632(1988).
[2]
SEQUENCE OF 22-30 AND 297-302.
OHMIYA M., HARA I., MASTUBARA H.;
PLANT CELL PHYSIOL. 21:157-167(1980).
-!- FUNCTION: THIS IS A SEED STORAGE PROTEIN.
-!- SUBUNIT: HEXAMER; EACH SUBUNIT IS COMPOSED OF AN ACIDIC AND A
BASIC CHAIN DERIVED FROM A SINGLE PRECURSOR AND LINKED BY A
DISULFIDE BOND.
-!- SIMILARITY: TO OTHER 11S SEED STORAGE PROTEINS (GLOBULINS).
EMBL; M36407; G167492; -.
PIR; S00366; FWPU1B.
PROSITE; PS00305; 11S_SEED_STORAGE; 1.
SEED STORAGE PROTEIN; SIGNAL.
SIGNAL
1
21
CHAIN
22
480
11S GLOBULIN BETA SUBUNIT.
CHAIN
22
296
GAMMA CHAIN (ACIDIC).
CHAIN
297
480
DELTA CHAIN (BASIC).
MOD_RES
22
22
PYRROLIDONE CARBOXYLIC ACID.
DISULFID
124
303
INTERCHAIN (GAMMA-DELTA) (POTENTIAL).
CONFLICT
27
27
S -> E (IN REF. 2).
CONFLICT
30
30
E -> S (IN REF. 2).
SEQUENCE
480 AA; 54625 MW; D515DD6E CRC32;
MARSSLFTFL CLAVFINGCL SQIEQQSPWE FQGSEVWQQH RYQSPRACRL ENLRAQDPVR
RAEAEAIFTE VWDQDNDEFQ CAGVNMIRHT IRPKGLLLPG FSNAPKLIFV AQGFGIRGIA
EAFQIDGGLV RKLKGEDDER DRIVQVDEDF EVLLPEKDEE ERSRGRYIES ESESENGLEE
TICTLRLKQN IGRSVRADVF NPRGGRISTA NYHTLPILRQ VRLSAERGVL YSNAMVAPHY
TVNSHSVMYA TRGNARVQVV DNFGQSVFDG EVREGQVLMI PQNFVVIKRA SDRGFEWIAF
KTNDNAITNL LAGRVSQMRM LPLGVLSNMY RISREEAQRL KYGQQEMRVL SPGRSQGRRE
CUCURBITA MAXIMA (PUMPKIN) (WINTER SQUASH).
EUKARYOTA; PLANTA; EMBRYOPHYTA; ANGIOSPERMAE; DICOTYLEDONEAE;
VIOLALES; CUCURBITACEAE.
[1]
SEQUENCE FROM N.A.
STRAIN=CV. KUROKAWA AMAKURI NANKIN;
MEDLINE; 88166744.
HAYASHI M., MORI H., NISHIMURA M., AKAZAWA T., HARA-NISHIMURA I.;
EUR. J. BIOCHEM. 172:627-632(1988).
(1 of ~100,000 entries)
Data ???
MARSSLFTFL
RAEAEAIFTE
IPGCAETYQT
FADTRNVANQ
...
CLAVFINGCL
VWDQDNDEFQ
DLRRSQSAGS
IDPYLRKFYL
NeSC, 25 April 2002
SQIEQQSPWE
CAGVNMIRHT
AFKDQHQKIR
AGRPEQVERG
FQGSEVWQQH
IRPKGLLLPG
PFREGDLLVV
VEEWERSSRK
//
RYQSPRACRL
FSNAPKLIFV
PAGVSHWMYN
GSSGEKSGNI
Why Don’t Scientists
Use Databases?
ENLRAQDPVR
AQGFGIRGIA
RGQSDLVLIV
FSGFADEFLE
6
Record (inadequate)
of history
DT
DT
DT
11SB_CUCMA
STANDARD;
PRT;
480 AA.
P13744;
01-JAN-1990 (REL. 13, CREATED)
01-JAN-1990 (REL. 13, LAST SEQUENCE UPDATE)
01-NOV-1990 (REL. 16, LAST ANNOTATION UPDATE)
11S GLOBULIN BETA SUBUNIT PRECURSOR.
CUCURBITA MAXIMA (PUMPKIN) (WINTER SQUASH).
EUKARYOTA; PLANTA; EMBRYOPHYTA; ANGIOSPERMAE; DICOTYLEDONEAE;
VIOLALES; CUCURBITACEAE.
[1]
SEQUENCE FROM N.A.
STRAIN=CV. KUROKAWA AMAKURI NANKIN;
MEDLINE; 88166744.
HAYASHI M., MORI H., NISHIMURA M., AKAZAWA T., HARA-NISHIMURA I.;
EUR. J. BIOCHEM. 172:627-632(1988).
[2]
SEQUENCE OF 22-30 AND 297-302.
OHMIYA M., HARA I., MASTUBARA H.;
PLANT CELL PHYSIOL. 21:157-167(1980).
-!- FUNCTION: THIS IS A SEED STORAGE PROTEIN.
-!- SUBUNIT: HEXAMER; EACH SUBUNIT IS COMPOSED OF AN ACIDIC AND A
BASIC CHAIN DERIVED FROM A SINGLE PRECURSOR AND LINKED BY A
DISULFIDE BOND.
-!- SIMILARITY: TO OTHER 11S SEED STORAGE PROTEINS (GLOBULINS).
EMBL; M36407; G167492; -.
PIR; S00366; FWPU1B.
PROSITE; PS00305; 11S_SEED_STORAGE; 1.
SEED STORAGE PROTEIN; SIGNAL.
SIGNAL
1
21
CHAIN
22
480
11S GLOBULIN BETA SUBUNIT.
CHAIN
22
296
GAMMA CHAIN (ACIDIC).
CHAIN
297
480
DELTA CHAIN (BASIC).
MOD_RES
22
22
PYRROLIDONE CARBOXYLIC ACID.
DISULFID
124
303
INTERCHAIN (GAMMA-DELTA) (POTENTIAL).
CONFLICT
27
27
S -> E (IN REF. 2).
CONFLICT
30
30
E -> S (IN REF. 2).
SEQUENCE
480 AA; 54625 MW; D515DD6E CRC32;
MARSSLFTFL CLAVFINGCL SQIEQQSPWE FQGSEVWQQH RYQSPRACRL ENLRAQDPVR
RAEAEAIFTE VWDQDNDEFQ CAGVNMIRHT IRPKGLLLPG FSNAPKLIFV AQGFGIRGIA
EAFQIDGGLV RKLKGEDDER DRIVQVDEDF EVLLPEKDEE ERSRGRYIES ESESENGLEE
TICTLRLKQN IGRSVRADVF NPRGGRISTA NYHTLPILRQ VRLSAERGVL YSNAMVAPHY
TVNSHSVMYA TRGNARVQVV DNFGQSVFDG EVREGQVLMI PQNFVVIKRA SDRGFEWIAF
KTNDNAITNL LAGRVSQMRM LPLGVLSNMY RISREEAQRL KYGQQEMRVL SPGRSQGRRE
01-JAN-1990 (REL. 13, CREATED)
01-JAN-1990 (REL. 13, LAST SEQUENCE UPDATE)
01-NOV-1990 (REL. 16, LAST ANNOTATION UPDATE)
Hierarchical data.
Order important.
RN
RP
RC
RX
RA
RL
RN
RP
RA
RL
ID
AC
DT
DT
DT
DE
OS
OC
OC
RN
RP
RC
RX
RA
RL
RN
RP
RA
RL
CC
CC
CC
CC
CC
DR
DR
DR
KW
FT
FT
FT
FT
FT
FT
FT
FT
SQ
[1]
SEQUENCE FROM N.A.
STRAIN=CV. KUROKAWA AMAKURI NANKIN;
MEDLINE; 88166744.
HAYASHI M., MORI H., NISHIMURA M., AKAZAWA T., HARA-NISHIMURA I.;
EUR. J. BIOCHEM. 172:627-632(1988).
[2]
//
SEQUENCE OF 22-30 AND 297-302.
OHMIYA M., HARA I., MASTUBARA H.;
PLANT CELL PHYSIOL. 21:157-167(1980).
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
7
Tree data (recursive
query processing?)
OC
OC
11SB_CUCMA
STANDARD;
PRT;
480 AA.
P13744;
01-JAN-1990 (REL. 13, CREATED)
01-JAN-1990 (REL. 13, LAST SEQUENCE UPDATE)
01-NOV-1990 (REL. 16, LAST ANNOTATION UPDATE)
11S GLOBULIN BETA SUBUNIT PRECURSOR.
CUCURBITA MAXIMA (PUMPKIN) (WINTER SQUASH).
EUKARYOTA; PLANTA; EMBRYOPHYTA; ANGIOSPERMAE; DICOTYLEDONEAE;
VIOLALES; CUCURBITACEAE.
[1]
SEQUENCE FROM N.A.
STRAIN=CV. KUROKAWA AMAKURI NANKIN;
MEDLINE; 88166744.
HAYASHI M., MORI H., NISHIMURA M., AKAZAWA T., HARA-NISHIMURA I.;
EUR. J. BIOCHEM. 172:627-632(1988).
[2]
SEQUENCE OF 22-30 AND 297-302.
OHMIYA M., HARA I., MASTUBARA H.;
PLANT CELL PHYSIOL. 21:157-167(1980).
-!- FUNCTION: THIS IS A SEED STORAGE PROTEIN.
-!- SUBUNIT: HEXAMER; EACH SUBUNIT IS COMPOSED OF AN ACIDIC AND A
BASIC CHAIN DERIVED FROM A SINGLE PRECURSOR AND LINKED BY A
DISULFIDE BOND.
-!- SIMILARITY: TO OTHER 11S SEED STORAGE PROTEINS (GLOBULINS).
EMBL; M36407; G167492; -.
PIR; S00366; FWPU1B.
PROSITE; PS00305; 11S_SEED_STORAGE; 1.
SEED STORAGE PROTEIN; SIGNAL.
SIGNAL
1
21
CHAIN
22
480
11S GLOBULIN BETA SUBUNIT.
CHAIN
22
296
GAMMA CHAIN (ACIDIC).
CHAIN
297
480
DELTA CHAIN (BASIC).
MOD_RES
22
22
PYRROLIDONE CARBOXYLIC ACID.
DISULFID
124
303
INTERCHAIN (GAMMA-DELTA) (POTENTIAL).
CONFLICT
27
27
S -> E (IN REF. 2).
CONFLICT
30
30
E -> S (IN REF. 2).
SEQUENCE
480 AA; 54625 MW; D515DD6E CRC32;
MARSSLFTFL CLAVFINGCL SQIEQQSPWE FQGSEVWQQH RYQSPRACRL ENLRAQDPVR
RAEAEAIFTE VWDQDNDEFQ CAGVNMIRHT IRPKGLLLPG FSNAPKLIFV AQGFGIRGIA
EAFQIDGGLV RKLKGEDDER DRIVQVDEDF EVLLPEKDEE ERSRGRYIES ESESENGLEE
TICTLRLKQN IGRSVRADVF NPRGGRISTA NYHTLPILRQ VRLSAERGVL YSNAMVAPHY
TVNSHSVMYA TRGNARVQVV DNFGQSVFDG EVREGQVLMI PQNFVVIKRA SDRGFEWIAF
KTNDNAITNL LAGRVSQMRM LPLGVLSNMY RISREEAQRL KYGQQEMRVL SPGRSQGRRE
EUKARYOTA; PLANTA; EMBRYOPHYTA; ANGIOSPERMAE; DICOTYLEDONEAE;
VIOLALES; CUCURBITACEAE.
Array indices (array
operations?)
FT
FT
FT
FT
FT
FT
FT
FT
ID
AC
DT
DT
DT
DE
OS
OC
OC
RN
RP
RC
RX
RA
RL
RN
RP
RA
RL
CC
CC
CC
CC
CC
DR
DR
DR
KW
FT
FT
FT
FT
FT
FT
FT
FT
SQ
SIGNAL
CHAIN
CHAIN
CHAIN
MOD_RES
DISULFID
CONFLICT
CONFLICT
NeSC, 25 April 2002
1
22
22
297
22
124
27
30
21
480
296
480
22
303
27
30
//
11S GLOBULIN BETA SUBUNIT.
GAMMA CHAIN (ACIDIC).
DELTA CHAIN (BASIC).
PYRROLIDONE CARBOXYLIC ACID.
INTERCHAIN (GAMMA-DELTA) (POTENTIAL).
S -> E (IN REF. 2).
E -> S (IN REF. 2).
Why Don’t Scientists
Use Databases?
8
Structure in comments
= schema evolution
CC
CC
CC
CC
CC
ID
AC
DT
DT
DT
DE
OS
OC
OC
RN
RP
RC
RX
RA
RL
RN
RP
RA
RL
CC
CC
CC
CC
CC
DR
DR
DR
KW
FT
FT
FT
FT
FT
FT
FT
FT
SQ
11SB_CUCMA
STANDARD;
PRT;
480 AA.
P13744;
01-JAN-1990 (REL. 13, CREATED)
01-JAN-1990 (REL. 13, LAST SEQUENCE UPDATE)
01-NOV-1990 (REL. 16, LAST ANNOTATION UPDATE)
11S GLOBULIN BETA SUBUNIT PRECURSOR.
CUCURBITA MAXIMA (PUMPKIN) (WINTER SQUASH).
EUKARYOTA; PLANTA; EMBRYOPHYTA; ANGIOSPERMAE; DICOTYLEDONEAE;
VIOLALES; CUCURBITACEAE.
[1]
SEQUENCE FROM N.A.
STRAIN=CV. KUROKAWA AMAKURI NANKIN;
MEDLINE; 88166744.
HAYASHI M., MORI H., NISHIMURA M., AKAZAWA T., HARA-NISHIMURA I.;
EUR. J. BIOCHEM. 172:627-632(1988).
[2]
SEQUENCE OF 22-30 AND 297-302.
OHMIYA M., HARA I., MASTUBARA H.;
PLANT CELL PHYSIOL. 21:157-167(1980).
-!- FUNCTION: THIS IS A SEED STORAGE PROTEIN.
-!- SUBUNIT: HEXAMER; EACH SUBUNIT IS COMPOSED OF AN ACIDIC AND A
BASIC CHAIN DERIVED FROM A SINGLE PRECURSOR AND LINKED BY A
DISULFIDE BOND.
-!- SIMILARITY: TO OTHER 11S SEED STORAGE PROTEINS (GLOBULINS).
EMBL; M36407; G167492; -.
PIR; S00366; FWPU1B.
PROSITE; PS00305; 11S_SEED_STORAGE; 1.
SEED STORAGE PROTEIN; SIGNAL.
SIGNAL
1
21
CHAIN
22
480
11S GLOBULIN BETA SUBUNIT.
CHAIN
22
296
GAMMA CHAIN (ACIDIC).
CHAIN
297
480
DELTA CHAIN (BASIC).
MOD_RES
22
22
PYRROLIDONE CARBOXYLIC ACID.
DISULFID
124
303
INTERCHAIN (GAMMA-DELTA) (POTENTIAL).
CONFLICT
27
27
S -> E (IN REF. 2).
CONFLICT
30
30
E -> S (IN REF. 2).
SEQUENCE
480 AA; 54625 MW; D515DD6E CRC32;
MARSSLFTFL CLAVFINGCL SQIEQQSPWE FQGSEVWQQH RYQSPRACRL ENLRAQDPVR
RAEAEAIFTE VWDQDNDEFQ CAGVNMIRHT IRPKGLLLPG FSNAPKLIFV AQGFGIRGIA
EAFQIDGGLV RKLKGEDDER DRIVQVDEDF EVLLPEKDEE ERSRGRYIES ESESENGLEE
TICTLRLKQN IGRSVRADVF NPRGGRISTA NYHTLPILRQ VRLSAERGVL YSNAMVAPHY
TVNSHSVMYA TRGNARVQVV DNFGQSVFDG EVREGQVLMI PQNFVVIKRA SDRGFEWIAF
KTNDNAITNL LAGRVSQMRM LPLGVLSNMY RISREEAQRL KYGQQEMRVL SPGRSQGRRE
-!- FUNCTION: THIS IS A SEED STORAGE PROTEIN.
-!- SUBUNIT: HEXAMER; EACH SUBUNIT IS COMPOSED OF AN ACIDIC AND A
BASIC CHAIN DERIVED FROM A SINGLE PRECURSOR AND LINKED BY A
DISULFIDE BOND.
-!- SIMILARITY: TO OTHER 11S SEED STORAGE PROTEINS (GLOBULINS).
//
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
9
To turn Swissprot into tables requires:
• 20 - 30 tables
– nothing extraordinary by relational
standards, but
– huge query to reconstruct original form
• Invented keys
• Queries on order and arrays
• Recursive query processing
• Also need to deal with schema evolution
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
10
Curated Databases
• Useful scientific databases are often curated : they
are created/ maintained with a great deal of “manual”
labour.
What really happens
DB2
DB1
Database people’s idea
of what happens
NeSC, 25 April 2002
select xyz
from pqr
where abc
Why Don’t Scientists
Use Databases?
11
Database Inter-dependence is Complex
GERD
EpoDB
TRRD
BEAD
TransFac
GenBank
GAIA
Swissprot
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
12
Three new topics
• Annotation
– how do I annotate a data element, and how
is this passed through queries?
• Archiving
– how do we keep all the old versions of a
database?
• Vertical partitioning.
– combining databases and vector
processing.
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
13
Data Annotation
(Khanna, Tan)
• Some databases (e.g. biology and linguistics)
are designed to accommodate annotations
• Also a need for ad hoc (unanticipated)
annotations.
– How are annotations communicated?
– How are they passed through queries?
• No general techniques or principles.
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
14
Sharing annotations
(courtesy of Wang-Chiew Tan)
Serves fine French Cuisine
in elegant setting. Jackets
required.
NYRestaurants (Source Table)
Cost
Restaurant
Peacock Alley
Bull & Bear
Pacifica
Soho Kitchen & Bar
Extensive wine list!
Type
Zip
$$$
$$$
French 10022
Seafood 10022
$
$
Chinese 10013
American 10022
Yummy chicken curry!!
Cheap Restaurants (View 2)
All Restaurants (View 1)
Restaurant
Peacock Alley
Bull & Bear
Pacifica
NeSC, 25 April
2002
Soho Kitchen
& Bar
Cost
$$$
$$$
$
$
Type
French
Seafood
Restaurant
Pacifica
Soho Kitchen & Bar
Chinese
Why Don’t Scientists
American
Use Databases?
Cost
$
$
Type
Chinese
American
15
Annotation looks simple but ...
• Computing how an annotation should move
through a query is intractable
• Equivalent queries may not carry annotations
in the same way
• New insights are needed!
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
16
How do we Build Archival Databases?
[Khanna, Tajima, Tan]
• Many scientific database keep archives. It’s
important to preserve the state of knowledge
as it was in the past
• Archive frequently: space consuming
• Archive infrequently: delay in getting recent
information published.
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
17
The dangers of electronic documents
Report of a DOE “bioinformatics summit” ca. 1994
http://www.ornl.gov/hgmis/publicat/miscpubs/bioinfo/inf_rep2.html#AppenI
Then:
APPENDIX I: SAMPLE QUESTIONS FOR A FEDERATED DATABASE
Continued HGP progress will depend in part upon the ability of genome databases
to answer increasingly complex queries that span multiple community databases.
Some examples of such queries are given in this appendix. Note, however,
until a fully relationalized sequence database is available,
none of the queries in this appendix can be answered. ...
Now:
APPENDIX I: SAMPLE QUESTIONS FOR A FEDERATED DATABASE
Continued HGP progress will depend in part upon the ability of genome databases
to answer increasingly complex queries that span multiple community databases.
Some examples of such queries are given in this appendix. Note, however,
until a fully atomized sequence database is available (i.e., no
data stored in ASCII text fields), none of the queries in this
appendix can be answered. ...
(No archive/edition! No footnote!)
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
18
Examples from Bioinformatics
• Swissprot. New version produced every four
months.
– Old versions are kept.
– Difficult to get at most recent data
• OMIM. New version produced every day
– Old versions are not kept
– Impossible to reconstruct past states of the
data
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
19
Current approaches use “diff”
Line
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Version 1:
Version 2:
Output of line diff (versions 1-2):
<DB>
<Person>
<Name>Joe</>
<DateOfBirth>March</>
<Address>South Street</>
<Zip>12345</>
</>
<Person>
<Name>Jane</>
<DateOfBirth>May</>
<Address>Pine Street</>
<Zip>67890</>
</>
</>
<DB>
<Person>
<Name>Jane</>
<DateOfBirth>May</>
<Address>South Street</>
<Zip>12345</>
</>
<Person>
<Name>Joe</>
<DateOfBirth>March</>
<Address>Pine Street</>
<Zip>67890</>
</>
</>
3,4c
<Name>Jane</>
<DateOfBirth>May</>
9,10c
<Name>Joe</>
<DateOfBirth>March</>
need to preserve “object continuity” through time
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
20
A Sequence of Versions
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
21
“Pushing” time down
[Driscoll, Sarnak, Sleator, Tarjan: “Making Data Structures Persistent.” ]
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
22
Size (bytes) x 106
Experimental Results
(OMIM)
Uncompressed
•
Legend
•archive
•inc diff
•version
•compressed inc diff
•compressed archive
gzip(inc diff)
Archive size is
–  1.01 times diff repository
size
–  1.04 times size of largest
version
Compressed
• archive size is between 0.94 and 1
times compressed diff repository size
• gzip - unix compression tool
• XMill - XML compression tool
XMill(archive)
Number of versions
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
23
Size (bytes) x 106
Legend
•archive
•inc diff
•version
•compressed inc diff
•compressed archive
Experimental Results
(Swissprot)
Uncompressed
• Archive size is
–  1.08 times diff repository
size
–  1.92 times size of largest
version
Compressed
• archive size is between 0.59 and 1
times compressed diff repository size
• gzip - unix compression tool
• XMill - XML compression tool
Number of versions
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
24
The Bottom Line
• We have built an archiver, using XML as the
base format
• We can build a year of archives (archive as
often as you like) for a 14% increase on the
size of the most recent database
• Based on keys -- preserves object history
• Works well with compression
• Obtaining an old archive is no more
expensive than getting the current version.
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Why Don’t Scientists
Use Databases?
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Vertical partitioning
• An old idea revisited
• Fusion of array processing languages and
database query languages
• Substantial use on Wall Street!!!
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
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Conventional Storage
Rows are stored contiguously.
Order is not preserved
(Horizontal partitioning)
disk pages
NeSC, 25 April 2002
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Problems with conventional storage
• Unanticipated queries will probably read the
whole database
SELECT average sqrt(shoe-size)
FROM employee
WHERE hat-size > shoe-size
(this only needs two fields)
• Order or rows is “random” and does not
support order-sensitive functions: moving
window averages, convolutions, etc.
NeSC, 25 April 2002
Why Don’t Scientists
Use Databases?
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Vertical partitioning (vectorisation)
Columns are stored contiguously.
Order is preserved
(Vertical partitioning)
disk pages
NeSC, 25 April 2002
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Advantages of Vertical Patitioning
• Faster queries.
– A query that reads 2 columns in 100 does 2% of the
i/o (i/o cost dominates)
– A few columns can often reside in memory.
• Computation on order
• Can use both SQL and vector processing languages
• Downside: deletions are horribly expensive.
– but deletions are uncommon in scientific DBs
• Vertical partitioning can also be performed on
hierarchical structures -- like Swissprot -- and XML
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Many other issues
• Heterogeneous data integration
– a perennial problem
– can it be done by the end-users?
• Distributed query evaluation against
redundant, constrained data.
• Data provenance
• Data streams
• and many more
All these involve hard, fundamental
problems in Computer Science
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