Title: Temporal Databases Managing time varying data Rob Squire UK Consulting
1Temporal Databases(Managing time varying
data)Rob Squire - UK Consulting
2Temporal Databases
Am I a good guy or a bad guy?
3Temporal Databases
- Interval Data Type (Timestamps)
- 6NF (horizontal and vertical decomposition aka
TNF) - Pack/UnPack (Collapsed form)
- No special attributes
- SQL with no extensions
4Temporal Databases
- What are temporal databases?
- What is time varying data?
- Implementation Approaches
- Why now?
- Demonstration
- Questions and Answers
5Temporal Databases
- What are temporal databases?
- What is time varying data?
- Implementation Approaches
- Why now?
- Demonstration
- Questions and Answers
6What are temporal databases?
- Non Temporal
- store only a single state of the real world,
usually the most recent state - classified as snapshot databases
- application developers and database designers
need to code for time varying data requirements
eg history tables, forecast reports etc
7What are temporal databases?
- Temporal
- stores upto two dimensions of time i.e VALID
(stated) time and TRANSACTION (logged) time - Classified as historical, rollback or bi-temporal
- No need for application developers or database
designers to code for time varying data
requirements i.e time is inherently supported
8What are temporal databases?
Valid (stated) Time
The 2 dimensions of time
Transaction (logged) Time
9What are temporal databases?
Valid (stated) Time
Granularity of the time axis Chronons can be
days, Seconds, milliseconds depending on the
application domain
Transaction (logged) Time
10What are temporal databases?
Valid (stated) Time
The moving point now
Transaction (logged) Time
11What are temporal databases?
- We can use these two dimensions to distinguish
between different forms of temporal database - A rollback database stores data with respect to
transaction time e.g. Oracle 10g has flashback
query - A historical database stores data with respect to
valid time - A bi-temporal database stores data with respect
to both valid time and transaction time.
12Temporal Databases
- What are temporal databases?
- What is time varying data?
- Implementation Approaches
- Why now?
- Demonstration
- Questions and Answers
13What is time varying data?
- You want a reprint of a customer's invoice of
August 12, 1999. - What was the stock value of the Oracle shares on
June 15th, last year? - What was the lowest stock quantity for every
product last year? How much money will you save,
if you keep the stocks at those levels? - Where do you enter the new address of this
customer as from the first of next month? - What will your profits be next month, given the
price list and cost prices by then?
14What is time varying data?
- And combinations of the situations can be very
complex - You offered these goods to the customer on
January 10 this year. What were the billing
prices and what was his discount level when you
sent him this offer? He has not accepted yet. Is
it smart to offer him an actualized discount now? - Given the final settlements for all the insurance
claims of the last three years, what will be the
minimum insurance premium your customers have to
pay next year?
15What is time varying data?
- Examples of application domains dealing with time
varying data - Financial Apps (e.g. history of stock market
data) - Insurance Apps (e.g. when were the policies in
effect) - Reservation Systems (e.g. when is which room in a
hotel booked) - Medical Information Management Systems (e.g.
patient records) - Decision Support Systems (e.g. planning future
contigencies) - CRM applications (eg customer history / future)
- HR applications (e.g Date tracked positions in
hierarchies)
16What is time varying data?
-
- In fact, time varying data has ALWAYS been in
business requirements but existing technology
does not deal with it elegantly!
17What is time varying data?
- Ask yourself two questions
- Does your business need to know the situation as
it was known at a particular date (e.g. the
reprint of the customer's invoice)? - Does your business use information that was
effective in the past or will become effective in
the future (e.g. the new address of the customer)?
18What is time varying data?
- If you answer "Yes" on one or both of these
questions then your data varies over time and you
could consider adopting a temporal approach
19Temporal Databases
- What are temporal databases?
- What is time varying data?
- Implementation Approaches
- Why now?
- Demonstration
- Questions and Answers
20Implementation Approaches
- Several implementation strategies are available
- Use a date type supplied in a non-temporal DBMS
and build temporal support into applications
(traditional) - Implement an abstract data type for time (object
oriented) - Provide a program layer (api) above a
non-temporal data model (stratum)
21Implementation Approaches
- Generalise a non-temporal data model into a
temporal data model (Temporal Normal Form) - Re-design core database kernel (Temporal Database)
22Implementation Approaches
-
- Q Why dont temporal databases already exist?
- A Dealing with time-varying data is complex
23Implementation Approaches
- For example
- Avoiding duplicates requires complex logic.
- Avoiding gaps in a time-varying data requires
complex logic. - A simple join when applied to time-varying data
turns into many lines of code consisting of
multiple FROM and WHERE clauses. - A simple update translates into several
modification statements requiring many lines of
code.
24Temporal Databases
- What are temporal databases?
- What is time varying data?
- Implementation Approaches
- Why now?
- Demonstration
- Questions and Answers
25Why now?
- Plummeting cost of storage
- Widespread adoption of warehouse technology has
led to an increasing interest in temporal
databases - The idea of maintaining and processing historical
data has become not just a goal but a reality for
many organisations
26Why now?
- DW vendors are themselves faced with temporal
problems (slowly changing time dimension) and
have begun to feel the need for a new solution - DB Vendors considering adding temporal support
to existing product (Oracle flashback query) and
applications (Oracle HR date tracking/payroll) - SQL bodies are beginning to think about adding
syntax to the standard to support temporal
features (SQL3, TSQL)
27Temporal Databases
- What are temporal databases?
- What is time varying data?
- Implementation Approaches
- Why now?
- Demonstration
- Questions and Answers
28Demonstration
- Temporal Normal Form (approach 4)
- Generate TNF for supplier, supplier part schema
- Show select, insert, update and delete operations
- Show Referential Integrity
- With a Temporal Data Dictionary
- Using simple standard SQL with no extensions
29Demonstration
Now
Fix Valid Time
30Demonstration
Timestamp or Now 2 days
Fix Valid Time
31Demonstration
Fix Transaction Time
SUPPLIER
Now
32Demonstration
Fix Transaction Time
SUPPLIER
Timestamp or Now - 2 days
33Demonstration
34Demonstration
Demo 01 Generating, populating and querying TNF
35Demonstration
Non Temporal Schema (SP)
TNF Temporal Schema (TSP)
SUPPLIER
SUPPLIER PART
Example schema taken from Temporal Data and the
Relational Model by CJ Date, H Darwin, NA
Lorentzos (2003)
36Demonstration
Non Temporal Schema (SP)
TNF Temporal Schema (TSP)
SUPPLIER
SUPPLIER
Generate
SUPPLIER PART
SUPPLIER PART
37Demonstration
Record Timestamp 1 03-NOV-05 15.45.23.125990000
38Demonstration
Non Temporal Schema (SP)
TNF Temporal Schema (TSP)
SUPPLIER
SUPPLIER
Populate Insert as Select from
SUPPLIER PART
SUPPLIER PART
39t0(now)
DEMO 1
Transaction time now
40t1(now)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
41Demonstration
Fix Valid Time
timestamp1
42t2(timestamp1)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
43Demonstration
Un Fix Valid Time
44t3 (now)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
45Demonstration
Fix Valid Time
Now 2 days
46t4 (now2days)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
47delete
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
48Demonstration
Un Fix Valid Time
49t5 (now)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
50eovt
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
51t6 (now)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
52Demonstration
Record Timestamp 2 03-NOV-05 15.57.04.334588000
53Demonstration
Now 30 seconds
Fix Valid Time
54t7(now30 seconds)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
55delete
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
56Demonstration
Un Fix Valid Time
57t8(now)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
58t9(now)
S1
S2
S3
S4
S5
DEMO 1
Transaction time now
59Demonstration
Demo 02 Fixing transaction time
60t10(now)
33
S1
S2
S3
S4
S5
DEMO 2
Transaction time now
61t11(now)
45
S1
S2
S3
S4
S5
DEMO 2
Transaction time now
62t12(now)
65
S1
S2
S3
S4
S5
DEMO 2
Transaction time now
63Demonstration
Fix Transaction Time
SUPPLIER
Timestamp 2
64t13(now)
171000
S1
S2
S3
S4
S5
DEMO 2
Transaction time lt t7
65t14(now)
170900
S1
S2
S3
S4
S5
DEMO 2
Transaction time lt t7
66t15(now)
170800
S1
S2
S3
S4
S5
DEMO 2
Transaction time lt t7
67Lifetime gt2 days
S1
S2
S3
S4
S5
DEMO 2
Transaction time lt t7
68Demonstration
UnFix Transaction Time
SUPPLIER
Now
69t16(now)
Lifetime 1 hour
S1
S2
S3
S4
S5
DEMO 2
Transaction time now
70Demonstration
Demo 03 (part1) DML not allowed when transaction
time is fixed
71Demonstration
Fix Transaction Time
Current Timestamp
72t17(now)
ORA-20001 S Cannot insert while system Y time
is set.
DEMO 3
Transaction time ltgt now
73Demonstration
UnFix Transaction Time
SUPPLIER
Now
74Demonstration
Demo 03 (part 2) Updating in TNF
75Demonstration
Now 10 days
Fix Valid Time
76t18(now-10days)
London
Paris
Paris
London
Athens
DEMO 3
Transaction time now
77Demonstration
Now 8 days
Fix Valid Time
78t19(now-8days)
London
Lyons
Paris
Paris
Lyons
London
Athens
DEMO 3
Transaction time now
79Demonstration
Now 6 days
Fix Valid Time
80t20(now-6days)
London
Lyons
Paris
Paris
Lyons
London
Corinth
Athens
DEMO 3
Transaction time now
81Demonstration
Now 4 days
Fix Valid Time
82t21(now-4days)
London
Manchester
Lyons
Paris
Paris
Lyons
Manchester
London
Corinth
Athens
DEMO 3
Transaction time now
83Demonstration
Un Fix Valid Time
84t22(now)
London
Manchester
Lyons
Paris
Paris
Lyons
Manchester
London
Corinth
Athens
DEMO 3
Transaction time now
85t18
t19
t20
t21
London
Manchester
Lyons
Paris
Paris
Lyons
Manchester
London
Corinth
Athens
DEMO 3
Transaction time now
86Demonstration
Demo 04 (part1) Maintaining Referential Integrity
87Demonstration
Un Fix Valid Time
88t23(now)
S
SP
ORA-20001 Integrity Constraint violated
parent key not found
DEMO 4
Transaction time now
(showing one S relvar)
89t23(now)
S
SP
DEMO 4
Transaction time now
(showing one S relvar)
90t23(now)
S
SP
DEMO 4
Transaction time now
(showing one S relvar)
91Demonstration
Demo 04 (part2) Foreign Key Rules for TNF
92Demonstration
Now 10 days
Fix Valid Time
93t24(now-10days)
S1
DEMO 4
Transaction time now
(showing one S relvar)
94Demonstration
Un Fix Valid Time
95t25(now)
S1
DEMO 4
Transaction time now
(showing one S relvar)
96Demonstration
Now 5 days
Fix Valid Time
97t26(now-5days)
S1
S1,P1
ORA-20001 Integrity Constraint violated
parent key not found
DEMO 4
Transaction time now
(showing one S relvar)
98t26(now-5days)
S1
delete restrict
S1,P1
Delete rule on foreign key constraint SP_S_FK is
RESTRICT
DEMO 4
Transaction time now
(showing one S relvar)
99t26(now-5days)
S1
delete cascade
S1,P1
Delete rule on foreign key constraint SP_S_FK is
CASCADE
DEMO 4
Transaction time now
(showing one S relvar)
100Demonstration
Un Fix Valid Time
101t27(now)
S1
S1,P1
DEMO 4
Transaction time now
(showing one S relvar)
102Demonstration
Demo 05 A more complex example
103Demonstration
UnFix Transaction Time
SUPPLIER
Now
104Demonstration
Now 100 days
Fix Valid Time
105S1,P1
S1,P2
S1,P3
S2,P4
S2,P5
S2,P6
S3,P1
S3,P3
S3,P6
S1,P4
S1,P5
DEMO 5
Transaction time now
(showing all SP relvars)
106S1,P1
S2
S1,P2
S3
S1,P3
S2,P4
S2,P5
S1
S1
S2,P6
S3,P1
S3,P3
QUERY A Page 74 List of dates each supplier was
able to supply at least one part
S3,P6
S1,P4
S1,P5
DEMO 5
Transaction time now
(showing all SP relvars)
107S1,P1
S1,P2
S1
S1,P3
S1
S1
S2,P4
S2
S2
S2,P5
S2,P6
S3
S3,P1
S3
S3,P3
QUERY B Page 75 List of dates each supplier was
unable to supply at least one part
S3,P6
S1,P4
S1,P5
DEMO 5
Transaction time now
(showing all SP relvars)
108Demonstration
Demo 06 (part1) The classic Employee Department
schema example
109Demonstration
Un Fix Valid Time
110Demonstration
UnFix Transaction Time
SUPPLIER
Now
111t28(now)
Dept 10, Sales, New York
DEMO 6
Transaction time now
(showing Dept relvar)
112t29(now)
Dept 10, Sales, New York
Dept 20, Finance, New York
DEMO 6
Transaction time now
(showing Dept relvars)
113t30(now)
Dept 10, Sales, New York
Dept 20, Finance, New York
Emp 1, John, Clerk,,Dept 10
DEMO 6
Transaction time now
(showing Dept/Emp relvars)
114Demonstration
Now 20 days
Fix Valid Time
115t31(now20)
Dept 10, Sales, New York
Dept 20, Finance, New York
Emp 1, John, Clerk,,Dept 10
DEMO 6
Transaction time now
(showing Dept/Emp relvars)
116Demonstration
Un Fix Valid Time
117t32(now)
Dept 10, Sales, New York
Dept 20, Finance, New York
delete restrict
Emp 1, John, Clerk,,Dept 10
ORA-20001 Integrity Constraint violated
parent key not found
DEMO 6
Transaction time now
(showing Dept/Emp relvars)
118t33(now)
Dept 10, Sales, New York
Dept 20, Finance, New York
delete cascade
Emp 1, John, Clerk,,Dept 20
DEMO 6
Transaction time now
(showing Dept/Emp relvars)
119Demonstration
Demo 06 (part2) Non Transferable foreign keys
120t33(now)
Dept 10, Sales, New York
Dept 20, Finance, New York
transferable
Emp 1, John, Clerk,,Dept 20
DEMO 6
Transaction time now
(showing Dept/Emp relvars)
121t34(now)
Dept 10, Sales, New York
Dept 20, Finance, New York
Non transferable
Emp 1, John, Clerk,,Dept 20
ORA-20001 Illegal attempt to modify
non-transferable foreign key.
DEMO 6
Transaction time now
(showing Dept/Emp relvars)
122t34(now)
Dept 10, Sales, New York
Dept 20, Finance, New York
Non transferable
Emp 1, John, Clerk,,Dept 20
DEMO 6
Transaction time now
(showing Dept/Emp relvars)
123Demonstration
- You have just seen
-
- A practical implementation of TNF
- Using Standard SQL
- Where existing data modelling techniques for
current view apply - Providing bi temporal support
- Can underpin any application development platform
(forms, java, html etc)
124Demonstration
- Next Steps
- Gather feedback and responses on TNF from Oracle
user organisations - Contact Oracle Expert Services
- 0870 550 3060
- expertservices_uk_at_oracle.com
- www.oracle.com/uk/expert_services
125Q
A
Q U E S T I O N S
A N S W E R S
Rob Squire UK Consulting rob.squire_at_oracle.com