??. ?a?a???t?? S?

1
???T???S ???????O? (Data Warehouses)

• ??. ?a?a???t?? S?µe???d??
• ???. ?e???????a? ?a? ?pe?e??as?a? ?ed?µ????
• ?µ?µa ?????f??????
• ??atµ?µat??? ?????aµµa ?etapt???a??? Sp??d??
• ???st?t??e?? ?a?ep?st?µ?? Tes/?????

http//delab.csd.auth.gr/symeon
2
On-Line Transaction Processing (OLTP) (1/3)

• S?st?µa ?pe?e??as?a? ??s??????? On-Line
  Transaction Processing (OLTP)
• ??a p???e? s?st?µa p?? pe????e? e??a?e?a ??a
  p????aµµat?sµ? efa?µ????, e?t??es? ?a? d?a?e???s?
  t?? d?s???????
• ??a t?t??a efa?µ??? p??pe? ?a d???e?e? s??e???,
  ?a a?tepe????eta? ap?t?????, e?e??sseta? s??e???,
  e??a? s?????? ?ata?eµ?µ??? ?a? pe???aµß??e?
• S?es?a?? ??s? ?ed?µ????
• ???t??
• ??????µµata efa?µ????
• ??a??et??? ???s?µ? ??a t? ?e?t?????a ???e
  ???a??sµ??

3
On-Line Transaction Processing (OLTP) (2/3)
OLTP ?e??p????? ?ta??e?a
???t?se ??a t?? ?. ? t?? ??s? 13? ??a ????a!
1
???t?se ??a t?? ?. Y t?? ??s? 1C ??a ??????a!
...
DB
??s?? ta??de???? ??a Tessa?????? ?
100
4
On-Line Transaction Processing (OLTP) (3/3)
OLTP ???pe?a
???e?a
?aµe??
DB
??st?t???? ???te?
???
5
OLTP ?as??? ?a?a?t???st???

• ?????st?? ?????? d?a??s?µ?? ??a t?? e?t??es? µ?a?
  d?s?????a?.
• ?e?????sµ???? a???µ?? p??sß?se?? st? d?s??.
• ?e?????sµ???? a???µ?? ?p?????sµ??.
• ??t? ???? ?e?t???????? apa?t?se??
• t??????st?? 100 TPS se µ?a ?? t?? t???? t?? 1 GB
• ??? ???? ?e?t???????? apa?t?se??
• µ???? 50000 TPS se µ?a ?? µe?a??te?? t?? 1 ?B.

6
???ß??µata s?es?a??? ??se?? ?ed?µ???? e??? OLTP

• ???et? ded?µ??a µp??e? ?a e??a? e???p? (missing
  data)
• ????????????S ??S??S
• ?p?????? e???af?? t?? ?p???? ??p??e? t?µ??
  ?e?p???
• ??t??at?stas? t?? t?µ?? p?? ?e?p??? µe t?? µ?s?
  t?µ? t?? ?at?????a?
• ??t??at?stas? t?? ap??s?? t?µ?? ?a?a?t???st????
  µe t?? a?t?st???e? t?µ?? pa??µ????
  ?a?a?t???st????

7
???ß??µata s?es?a??? ??se?? ?ed?µ???? e??? OLTP

• ???et? ded?µ??a µp??e? ?a ????? ????ß? ?a?
  as???pe?e? (Noisy and inconsistent data)
• ??t?p?sµ?? d?p??t?p?? e???af??
• p.?. S?µe???d?? S?µa????d??
• ??t?p?sµ?? ?a??asµ???? t?µ?? ?a?a?t???st????
• p.?. ??de???? t?µ? se ??a ?a?a?t???st??? p??
  af??? t? ß???? p?????t??
• ???µ????s? ded?µ????
• p.?. pe?????sµ?? t?? a???µ?? t?? t?µ?? e???
  a???µ?t???? ?a?a?t???st????

8
???ß??µata s?es?a??? ??se?? ?ed?µ???? e??? OLTP

• ?a ded?µ??a µp??e? ?a e??a? ete???e?? ?a? ?a
  pa???s?????? s?????µ?e? ? aµf?s?µ?e?
• ?.?., pe??t?? ?ata????µ???? µe d?af??et???
  st???e?a st? ß?s?? t?? tµ?µat?? p???se?? ap? ?t?
  st? ß?s? t?? tµ?µat?? µ???et????.

9
???????????? e?a?µ???s?
EMP ID Name Birth Salary Total Income DeptID
110 Kostas 1/1/72 1500 1200 132

Source 1 Personnel (Cobol)
EMP ID IL_ID Amount
110 10 1500
110 30 300
EMP INCOME
Source 2 Accounting (DB2)
IL_ID Descr
10 ??s???
20 ?p?d?µa ??????
30 F????
... ...
EMP ID Name Age
110 Kostas 30
120 Vasilis 48
130 Roula 29
EMP
Income Lookup
10
?p??a??????p???s? - Denormalization
IL_ID Descr
10 ??s???
20 ?p?d?µa ??????
30 F????
... ...
EMP ID IL_ID Amount
110 10 1500
110 30 300
EMP INCOME
Income Lookup
EMP ID Name Age
110 Kostas 30
120 Vasilis 48
130 Roula 29
EMP
DW
DW.EMP
?
11
?a?a??sµ?? t?? ded?µ???? ?µ??e??p???s? ??e?d???
ID Descr
100 Coca
110 Pepsi
120 Epsa
ID Descr
10 Coca
20 Pepsi
DW.R
R1

ID Descr
10 Pepsi
20 Epsa
Source ID Source Surrogate Key
10 R1 100
20 R1 110
10 R2 110
20 R2 120

R2
Lookup
12
???ß??µata s?es?a??? ??se?? ?ed?µ???? e??? OLTP

• ???? d?ad??as??? e??µ???s??, e?sa?????, d?a??af??
  d?at????? ded?µ??a µ??? ??a t?? t?????sa
  ?at?stas?.
• ?.?., st? ß?s? t?? tµ?µat?? p??µ??e???
  d?at?????ta? µ??? ?s?? p??µ??e?t?? s??e??????ta?
  a?t? t? st??µ? e?? µp??e? ?a ??e?as???? ded?µ??a
  ?a? ??a p??µ??e?t?? p?? s??e??a??ta? st? pa?e????
  p???e?µ???? ?a s????????? ?? t?µ?? t???
• ? a????s? t?? ded?µ???? de? e??a? e????? ?a
  ep?te???e? µe e??a?e?a ?p?? ? ???ssa SQL.
• ?????pt??? pe??p???a e??t?µata SQL ta ?p??a de?
  e??a? e????? ?a s??ta?????.

13
???ß??µata s?es?a??? ??se?? ?ed?µ???? e??? OLTP

• Se f?s??? ep?ped? ??????s?? (p.?. de?d?????
  µ???d?? p??sp??as??) de? e??a? s?ed?asµ??a ??a ?a
  a?tap???????ta? st?? apa?t?se?? pe??p?????
  e??t?µ?t??.
• ?a ded?µ??a ???a?????ta? µe ?????aµµa
  ??t?t?t??-S?s?et?se?? (??S) ?a? a???? ?p?? ?
  ?a??????p???s?, p?? pa?????? pe??p???e? ß?se??
  st? ???t??? ep?ped?

14
On-Line ?nalytical Processing (OLAP OLAM)

• A????s? µe????? ????? s???et?? ded?µ???? ap?
  d?af??et???? efa?µ????
• ??d???? t?p?? e??t?µata s???????s??
• ?pt???p???s?/stat?st??? a????s?/p???d??stat?
  a????s?
• ??????? G??s?? (Knowledge Discovery/Data Mining)
• ??e??es? p??t?p?? se te??st?e? ß?se?? ded?µ????
• OLAP Data Mining gt On-Line Analytical Mining

15
?a?ade??µata e??t?se?? OLAP

• ????? ?ta? ? ????? p???se?? a?? pe????? ?a?
  ?at?????a p?????t?? t?? pe?asµ??? ??????
• ??s? s?et????ta? ?? a???se?? t?µ?? t??
  ?p?????st?? µe ta ???d? t?? p???se?? ta 10
  te?e?ta?a ?????a
• ???a ?ta? ta d??a p??ta ?atast?µata se p???se??
  CD
• ?? p?s?st? ap? t??? pe??te? p?? a????????
  a?a???t??? a???????? ?a? patat???a

16
?e?t??????? ?a?a?t???st??? ?pa?t?se?? OLAP

• ???sßas? se µe???? ???? ded?µ????
• S?µµet??? a????st???? ?a? ?st?????? ded?µ???? se
  p???p???e? e??t?se??
• ?etaß??? t?? ?pt???? ????a? pa???s?as?? t??
  ded?µ???? (p.?., ap? p???se?? a?? pe????? -gt
  p???se?? a?? tµ?µa ??p.)
• S?µµet??? p???p????? ?p?????sµ?? (p.?.
  stat?st???? s??a?t?se??)
• G?????? ap??t?s? se ?p??ad?p?te ??????? st??µ?
  te?e? ??a e??t?µa ( On-Line).

17
OLTP vs. OLAP

• OLTP OLAP
• ?e?t?????e? ??t?µat?sµ?? ???a??
  ?a??µe????? st?at?????? e??as???
• ??p?? ?ed?µ???? ?ept?µe?? ?????st???
• ????? ?ed?µ???? 100 GB 1 TB
• F?s? ?ed?µ???? ???aµ??? Stat???, Ist?????

18
OLTP vs. OLAP
OLTP OLAP I/O ??p?? ?e?????sµ???
I/O ??tetaµ??? I/O ???p?p???se?? S??e?e??
?e???d???? ???µe??se?? F??t?? ??s?????e?
µe ???t?se?? p?? p??sßas? ?????
sa?????? e???af?? e?at?µµ???a
e???af?? S?ed?as? ?? ?ate?????µe??
?ate?????µe?? ap? ?fa?µ??? ap?
?e??e??µe??
19
OLTP vs. OLAP
OLTP OLAP ??p???? ???ste? ?aµ???ßa?µ??
?p. ?????ßa?µ?? ?p. ???s? ??s?
Ad-hoc p???atas?e?asµ???? f??µ?? ????µ
?? ???st?? ?????de? ?e??de? ?st?as? ??sa????
??a???? ?ed?µ???? ?????f?????
20
?p????e? ded?µ????

• ? te???????a t?? ap?????? ded?µ???? p??sf??e?
• ????????s? ete???e??? p???? ded?µ???? ?a?
• p?atf??µa ??a ap?d?t??? a????s? ?st??????
  ded?µ????
• ??a ap????? ded?µ???? ap?te?e? µ?a s??????
  ded?µ???? p??
• ep??????ta? ap? t?? ?p??e???s?a??? ??se??
  ?ed?µ????,
• ???????????ta? (integrated),
• ta ded?µ??a a?a????ta? µe d?ad??as?e? ?p?? ?
  On-line Analytical Processing (OLAP) ? ? e??????
  ded?µ????.

21
?p????e? ded?µ????

• ??a ?e?t????p???µ??? ?? µe s??p?
• t?? ????????s? (integration) ete???e??? p????
  p????f????? (data sources) gt s???????s? ???? t??
  e?d?af????sa? p????f???a? se µ?a t?p??es?a
• t?? ap?f??? t?? s??????s?? µeta?? OLTP ?a? OLAP
  (DSS) s?st?µ?t?? gt ap?d?s? efa?µ???? ?a?
  d?a?es?µ?t?ta t?? s?st?µat??
• ?p??e? ?a s?µp?????eta? ?a? ap? e?e?d??e?µ??a
  ?eµat??? ?p?s????a (Data Marts) ??a pe?a?t???
  ap?d?s? t?? OLAP efa?µ????

22
?p????e? ded?µ???? ?e?t??????? ?a?a?t???st???

• ?st????? ?ed?µ??a
• ? ???????? ??????ta? µ?a ap?????? ded?µ????
  e??a? p??? µe?a??te??? ap? ?t? e??? s?st?µat?? se
  ?e?t?????a
• ? ?? ??e? ta t????? ded?µ??a e?? ?? ap????e?
  d?at????? ?a? pa??? ded?µ??a (p? ta p??????µe?a
  5-10 ?????a)

• ???p?p???se??
• ?? t??p?p???se?? st?? p???? ded?µ???? de?
  fa????ta? ?µesa st?? ap????e? ded?µ????, s??????
  pe???d???
• ???? d?? ßas???? ?e?t?????e? a????? f??t?µa
  t?? ded?µ???? (loading) ?a? p??sp??as? ded?µ????
  (access)

23
?p?t???a ap?????? ded?µ???? (1/2)

• ???te? p??sp??e?e? sta µ?sa t?? de?aet?a? t??
  1990, ?p?te ?? ap????e? ded?µ???? e?e??????a? se
  a???? t?? t???? t?? 2 d?? .
• Sta t??? t?? de?aet?a? t?? 1990, t? 95 t?? 1000
  ep??e???se?? t?? Fortune a??pt?ssa? ap????e?
  ded?µ????, ?p?te ? a???? t?? ap?????? ded?µ????
  a????e ??????µ??? t?? t???? t?? 7 d?? .
• ??t?µ????e ?t? se 3 ?????a ap? t?? a??pt??? µ?a?
  ap?????? ded?µ????, ? ap?sßes? ???eta? se p?s?st?
  400.

24
?p?t???a ap?????? ded?µ???? (2/2)

• ?p?t???µ??? pe??pt?s? efa?µ????
• a??s?da ?pe?a????? Walmart, µe 2000
  ?p??atast?µata.
• ß????se t?? Walmart ?a ße?t?st?p???se? t??
  d?ad??as?e? p??µ??e?a? p?????t?? ?a? ?a µe??se?
  t? ??st?? a????? t??? ?at? 20.
• ? ????? t?? ded?µ???? st?? ap????? ded?µ???? t??
  Walmart a????eta? sta 24 ??, se ??a s?st?µa 96
  ??µß?? µe 900 epe?e??ast?? ?a? 2700 d?s????.

25
?p????e? ded?µ???? ?as???? ?e?t?????e?
26
????te?t????? ap?????? ded?µ????
27
?etas??µat?sµ?? ?ed?µ????

• ?a??????p???s? ?ed?µ????
• ?etat??p? t?p?? ded?µ????
• ?p????? ?a?a?t???st???? ?a? st??µ??t?p??

28
?a??????p???s? ?ed?µ????

• ?e?ad??? ???µ???s?
• ?a??????p???s? ??a??st??-?e??st??
• ?a??????p???s? µe ???s? t?µ?? Z-scores

29
???t??? ????d??stat?? ?ed?µ???? (??ß??) ?a?
?e?t?????e? p?? e?te????ta? se a?t?
30
???sµ?? ??ß?? ded?µ????
??a ap????? ded?µ???? ßas??eta? se ??a
p???d??stat? µ??t??? ded?µ???? (multidimensional
data model) p?? a?apa??st? ta ded?µ??a µe t?
µ??f? e??? ??ß?? ded?µ???? (data cube) ??a?
??ß?? ded?µ???? (data cube) ep?t??pe? t??
µ??te??p???s? ?a? t?? ?e???s? t?? ded?µ???? ap?
p????? ?pt???? ????e? ??ast?se??
(dimensions) G?a s???e???µ??e? t?µ?? st??
d?ast?se?? µ?a ??t??s? (Measure) af??? a?t? p??
µa? e?d?af??e? ?a µet??s??µe
??ß?? ?O??S??S
Location
Item
Time
??ast?se??
??t??s? ????µ?? ????se?? ??a t?? s???e???µ??e?
d?ast?se?? (Location, Item, Time)
31
?e?a???e? ??ast?se??
???e d??stas? pa???e? t?µ?? ap? d?af??et???
ep?peda, µp??e? ?a e?f?aste? se d?af??et???
ep?peda ?ept?µ??e?a?
??ß?? ?O??S??S
Location
??ast?se?? Product, Region, Date?e?a???e?
d?ast?se??
Country
Industry
Year
Category
Item
Region
Quarter
City
Week
Product
Month
Time
??t??s? ????µ?? ????se?? ??a t?? s???e???µ??e?
d?ast?se?? (Location, Item, Time)
Day
Store
32
?a??de??µa ???????????? ?e?a???a (Concept
Hierarchy) ??a Location
all
all
Europe
North_America
...
region
Mexico
Canada
Spain
Germany
...
...
country
Vancouver
...
...
Toronto
Frankfurt
city
M. Wind
L. Chan
...
office
33
???t??? ?ed?µ???? S??µat?? ?st??a

• S??µa ?st??? (Star schema)
• ???a?a? ?e????t?? st? ???t?? p?? s??d?eta? µe
  ??a s????? ap? p??a?e? d?ast?se??
• ???a?a? ?e????t?? (Fact Table) ??e? ??
  ?????sµata
• t?? µet??se?? (p? a???µ?? p???se??, t?µ? se
  d?????a, ??p)
• t? p??te??? ??e?d? ???e s?et???? p??a?a
  d?ast?se??
• ???a?e? ??ast?se??
• ???a?a? µe p????f???a s?et??? µe ???e d??stas?
• ?tem (item_name, brand, type),
• ?ime(day, week, month, quarter, year)

34
?a??de??µa S??µat?? ?ste????

???a?a? Ge????t?? ?O??S??S
time_key
item_key
branch_key
location_key
units_sold
dollars_sold
avg_sales
?et??se??
4 d?ast?se?? (time, item, location, branch)
35
???t??? ?ed?µ???? S??µat?? ???????f?da?
(Snowflake schema)

• ???a? µ?a ße?t??s? t?? s??µat?? ast??a s?µf??a
  µe t?? ?p??a ? ?e?a???a d?ast?se?? t?? p??????
  d??stas?? ?a??????p??e?ta? se ??a s????? ap?
  µ????te???? p??a?e? d?ast?se??

36
?a??de??µa S??µat?? ???????f?da?
item
???a?a? Ge????t?? ?O??S??S
supplier
item_key item_name brand type supplier_key
supplier_key supplier_type
time_key
item_key
branch_key
branch
location_key
branch_key branch_name branch_type
units_sold
dollars_sold
avg_sales
?et??se??
37
???t??? ?ed?µ???? - ?ste??sµ?? Ge????t?? (Fact
constellations)

• ?as??eta? se ????ap???? ???a?e? Ge????t?? p??
  µ???????ta? t??? ???a?e? ??ast?se??.
• ?p????µe ?a t??? d??µe ?? s?????? ap? ast???a ?
  ?a?a??e?

38
?a??de??µa S??µat?? ?ste??sµ?? Ge????t??
???a?a? Ge????t?? ???S????
???a?a? Ge????t?? ?O??S??S
time_key
item_key
time_key
shipper_key
item_key
from_location
branch_key
to_location
location_key
dollars_cost
units_sold
units_shipped
dollars_sold
avg_sales
?et??se??
39
??ß?? ?ed?µ???? - ???????a
S???? ? n-D ??ß?? ???eta? ßas???? ??ß?e?d?? (base
cuboid). ?e????e? t?? µe?a??te?? ßa?µ??
?ept?µ??e?a?. p.?. G?a ??ß? µe t?sse?e??
d?ast?se?? (Item, Time, Branch, Location) ????µe
4-D ßas??? ??ß?e?d? O 0-D cuboid pe????e? t?
µe?a??te?? ep?ped? pe??????? (apex cuboid). ??
p???µa ???? t?? ??ß?e?d?? ???µ??eta? ??ß??
ded?µ????.
40
????µa ??ß?e?d?? ??ß?? ded?µ????
all
0-D(apex) cuboid
time
item
location
supplier
1-D cuboids
time, item
time , location
item, location
location, supplier
2-D cuboids
time, supplier
item, supplier
time, location, supplier
3-D cuboids
time, item, location
time, item, supplier
item, location, supplier
4-D (base) cuboid
time, item, location, supplier
41
OLAP ?a? s???????s?

• G?a t?? efa?µ??? OLAP p???e?? apa?te?ta? ?
  ???sµ?? t?? t??p?? pa?a????? t??
  ??ß??-ap?te?esµ?t??, µ?s? µ?a? s??a????st????
  s????t?s??
• ?? ßas???? s??a????st???? s??a?t?se?? e??a?
• a????sµat?? (sum),
• p?????? (count),
• µ?s?? ???? (avg),
• µe??st?? (max), ?a?
• e?a??st?? (min).

42
?et??se?? - S??a????se??

• ??t?? ap? t?? ?ept?µe?e?? p????f???e? t?? fact
  tables, µp??e? ?a ?p?????s??µe ?a? s??a????se??
  t?? ded?µ???? ??a ?a??te???? ??????? ap????s??.
• G?a pa??de??µa, a? ? fact table e??a?
• SALES(GeographyCode, ProductCode, TimeCode,
  BrandCode, Amount, Unit)
• µp????µe ?a ?p?????s??µe
• AVG(amount) a?? Region, Product, Quarter
• SUM(amount) a?? City
• MAX(units) a?? Brand, Month, µe Region Europe

43
?a??de??µa S??a????se?? (1/2)
Total annual sales of TV in U.S.A.
Date

2Qtr
1Qtr
sum
3Qtr
4Qtr
TV
Product
U.S.A
PC
VCR
sum
Canada
Country
Mexico
Total annual sales of TV in All countries
Total annual sales of all Devises in All
countries
44
?a??de??µa S??a????se?? se p??a?a ?e????t?? (2/2)
??tetaµ???? p??a?a? p???se?? ??s?µ?t?s? t??
a????st???? e???af?? st?? ßas??? fact table µ?a
ep?p???? st??? p?? ?a e???e? t? ep?ped?
s???????s??
????st?? p??a?a?/??? a????sµ?t??
Sales table
sum
Extended Sales table
City-dimension sum table
45
?as???? ???eß????? ????e??

• S??a????st??? ???d?? (Roll up) s???????s? t??
  p????f???a? µet?ßas? ap? ?aµ???te?? se
  ?????te?? ep?ped? ?e?a???a? (p.?. ap? day se
  month)
• ??a??t??? ????d?? (Drill down) t? a?t?st??f? t??
  Roll up (p.? month se day)
• ??????t??? ?eµa??sµ?? (Slice) p???? t?? ep??????
  e???af?? (where) ap? µ?a d??stas?.
• ???et?? ?eµa??sµ?? (Dice) p???? t?? ep?????? ap?
  pe??ss?te?e? d?ast?se??.
• ?e??st??f? (Pivot) a?ad??ta?? t?? p??ß???? t??
  p???d??stat?? ??ß?? st?? ?????

46
????? S??a????st???? a??d?? Roll-up

• ? s??a????st??? ???d?? pe???aµß??e? t??
  ?p?????sµ? µ?a? s???????? t?µ?? ??a µ?a ??s? st??
  ?e?a???a µ?a? d??stas?? ded?µ????.
• G?a pa??de??µa, µe ??a roll-up, ?? p???se?? se
  ep?ped? t?p???? µa?a???? (Store) pa?????? t??
  s???????? p???se?? se ep?ped? p???? (City) ?a?
  a?t?? µe t? se??? t??? µe ??a a??µa roll-up
  pa?????? t?? p???se?? se ep?ped? pe??????
  (Region).

47
?a??de??µa ?????? Roll-up
?????? ?p?ped? Quarter
?????? ?p?ped? Year SUM(Sales volumes in dollars)
48
????? ??a??t???? ?a??d?? Drill-Down

• ? ???st?? pe??? ap? ??a a??te?? ep?ped? µ?a?
  d??stas?? p?? ??e? s???e?t??t??? ded?µ??a se ??a
  ?aµ???te?? ep?ped? µe p?? ?ept?µe?? ded?µ??a.
  ????e?ta? ??a t?? a?t?st??f? p???? t?? roll-up.
• G?a pa??de??µa, ?at? t? drill down, ?e????µe ap?
  t?? p???se?? a?? pe????? (Region) ?a? pa?????µe
  t?? a?a??t???? p???se?? a?? p??? (City) ?a? µet?
  t?? p???se?? a?? ?at?st?µa (Store).

49
?a??de??µa ?????? Drill-Down
Item ?p?ped? Industry
Item ?p?ped? Category
50
????? ?e??st??f?? (Pivot)

• ??a??a?? t?? ??aµµ?? ?a? t?? st???? t?? ??ß??,
  ?p?? a?t?? pa???s???eta? st?? ?????
• ?e? apa?te?ta? ?a???a? ???? ?p?????sµ?? st? ??

51
?a??de??µa ?????? Pivot
??a??a?? ??aµµ?? ?a? st????
52
??????t??? ?eµa??sµ?? (slice)

• Slice ?p????? s???e???µ???? t?µ?? ap? µ?a
  d??stas? (where t?? SQL) p.?.

?p??e?e t? 1o t??µ??? ap? t?? d??stas? ?µe??µ???a
52
53
???et?? ?eµa??sµ?? (dice)

• Dice ?p????? s???e???µ???? t?µ?? ap?
  pe??ss?te?e? d?ast?se?? (e???e? ??a? ?p???ß?)

54
?a??de??µa ??ß???p??e???

• 20 ?p??atast?µata ?a? sta p??te ?e???af???
  d?aµe??sµata t?? ????da?
• Se ???e ?p??at?st?µa ?p?????? 3 tµ?µata t??
  ß?ß????, t?? ??e?t??????? µ?s?? ?a? t?? e?d??
  ??afe???.
• ?? ep??e???µat???? d?ad??as?e? t?? ß?ß???p??e???
  pe???aµß????? t?? p???se?? p?????t??
• ??a ap? t?? s?µa?t???te?e? ap?f?se?? st??
  ep??e???s?, ap?te?e? ? t?µ?????s?/??st?????s? t??
  p?????t??.

55
4 s?ed?ast??? ß?µata ??a t? s??µa ast??a

1. ?p????? t?? d?ad??as?a? p?? ?a µ??te??p????e?
2. ?p????? ep?p?d?? ?ept?µ??e?a?
3. ?p????? t?? p?????? d?ast?se??
4. ?p????? t?? a???µ?t???? ?e????t?? (µet??se??)

56
?a 4 ß?µata ??a t? ß?ß???p??e??

• ?p????? t?? d?ad??as?a? p?? ?a µ??te??p????e?
• ???te?a??t?ta st? µ??te??p???s? t?? d?ad??as?a?
  p???se?? (p???? ???s?µ?)
• ?p????? ep?p?d?? ?ept?µ??e?a?
• ?s? t? d??at?? µe?a??te?? ep?ped? ?ept?µ??e?a?
  ?ata???f??µe ?e????st? ???e at?µ??? s??a??a??
  e??? pe??t?
• ?p????? t?? p?????? d?ast?se?? (p??e?
  p????f???e? pe?????f??? ???e ??aµµ? t?? p??a?a
  ?e????t??)
• pe??t??, p?????, ?µe??µ???a, ?p??at?st?µa,
  s??a??a??
• ?p????? t?? a???µ?t???? ?e????t?? (t? µet??µe se
  ???e ??aµµ? t?? p??a?a ?e????t??)
• a???µ?? teµa????, ??st?? p???s??

57
S??µa ast??a ??a t? ß?ß???p??e??
58
??ß?? ded?µ???? ??ß???p??e??? (????? d??stas?
pe??t?)
?et???? (measure)
?eµ???a
?e?a???e? ??ast?se??
59
????e?? OLAP
60
????e?? Roll-up Drill-Down
61
???T???S ???????O? (Data Warehouses)

• ??. ?a?a???t?? S?µe???d??
• ???. ?e???????a? ?a? ?pe?e??as?a? ?ed?µ????
• ?µ?µa ?????f??????
• ??atµ?µat??? ?????aµµa ?etapt???a??? Sp??d??
• ???st?t??e?? ?a?ep?st?µ?? Tes/?????

http//delab.csd.auth.gr/symeon