[PPT] - Nested T ransactions in a Logical Language fo r Active PowerPoint Presentation

SLIDE 1 Nested T ransactions in a Logical Language fo r Active Rules Bertram Lud

ascher

W

lfgang

Ma y Geo rg Lausen Institut f ur Info rmatik Universit

at

F reiburg Germany Overview

Intro

duction Deductive vs Active Rules

Flat

Statelog and F riends Unifying Active and Deductive Rules

Pro

cedures and Nested T ransactions

Conclusion

and Outlo

k
LID

SLIDE 2 Intro duction Deductive Rules ak a Datalog

p
w

erful query language decla rative semantics

IC

checking

static

description

f

the mo deled w

rld
no

supp

rt

fo r up dates and reactive b ehavio r Active Rules

reactive

b ehavio r esp eciallyup dates

view

maintenance IC enfo rcement monito ring applications

semantics

p redictabilit y

f

rule eects termination

a

Unied F ramew

rk

fo r Active and Deductive Rules Up date

Active

Rules

Logic
Datalog
X
LID

SLIDE 3 Execution Mo del Datalog vs Statelog Queries Answ ers P

tcXY
S

D Datalog S

events

S f inal

actions

Queries Answ ers P

tcXY
delQX
delTXY
S

RX

S

insRX

S

D

S
D
S
nD
S

f inal D BOT EOT Flat Statelog

LID

SLIDE 4 Flat Statelog Syntax UserDened Rules Queries S

tcXY
tcXZ

tcZY Integrit y Constraints S

ab
rt
Up

dates

empD

REFERENCES deptD ON DELETE CASCADE S

delempESalD
deldeptD
empESalD

SystemDened Rules F rame Rules S

RX
S
RX

not delRX S

RX
S
insRX

Integrit y Constraints S

ab
rt
insRX

delRX

LID

SLIDE 5 Flat Statelog Semantics

Exp

ressive P

w

er Standa rd LP Semantics S

pX
S
not

qY

psuccSX
qSY
pX
qY

Exp ressivenessComplexit y

Flat

Statelog

WhilePFP
PSP

A CE

n
rdered

DBs

monotone

Statelog

Fixp
intLFP
PTIME
n
rdered

DBs termination gua ranteed

Gua

rded Statelog

Stratied

Datalog

PTIME
n
rdered

DBs Related App roaches XYDatalog Zaniolo Datalog S T emplog ChomickiBaudinet ELSDatalog KempRamamohana raoStuck ey Datalog

Abiteb
ulVianu

HeraclitusAlgC Ghandeha rizadeh etal

LID

SLIDE 6 Flat Statelog Problems Hire emplo y ee E with sala ry Sal fo r depa rtment Dept p rovided the average sala ry after the up date do es not exceed a certain limit S

insempsalESalinsemp

depEDept S

checksalDept
S
hireE

Sal Dept S

check
k
checksalDept

avgDept Amt Amt

S
delempsalESaldelemp

depEDept

S
hireESalDept

S

not

check

k

Problems

Undoing

the eect

f

changes has to b e p rogrammed explicitly

There

is no structure which allo ws grouping

f

semantically closely related rules

The

eects

f

ephemeral up dates zanioloDOOD and hyp

thetical

up dates a re visible to

ther

rules since there is no encapsulation

group

rules into p ro cedures which execute as nested transactions

LID

SLIDE 7 Pro cedures and Nested T ransactions

A

Statelog p ro cedure

is

a set

f

lo cal Statelog rules

A

p ro cedure

denes

a transaction T

at

runtime The b ehavio r

f
is

encapsu lated

If
calls
then

T

executes

as subtransaction

Simultaneously

called p ro cedures

and
execute

indep endently and in isolation

SubT

ransactions execute atomically allo rnothing

LID

SLIDE 8 UserDened Rules Pro cedures p ro c

A
A

n

OI
I

k

M

O

O

l

initial

P initial

alw

a ys P al w ay s

nal

P f inal

endp

ro c O R

imp
rt

EDBIDB relation R M R

exp
rt

EDB relation R Rules Views S

V
X
V
I

D B P

Change

Requests S

ins

R

X
S
delR
X
R
E

D B P

S
mo

d R

X
X
Pro

cedure Calls S

X
P

r

cP
External

Actions S

A
X
A
Act

P

T

ransaction Control S

ab
rt
ab
rt
C

tl P

all

userdened rules a re lo cal

LID

SLIDE 9 Nested T ransactions State Space F

F

n F

F
F
F
F
F
F
m

F

F
m
F
F
F
k
F
T

ransaction F rames F

F
F
States

F n

F

n

F
m
LID

SLIDE 10 SystemDened Rules Deltas S

R
X
S
ins

R

X
not

EOT S

R
X
S
R
X
not

delR

X
not

EOT

Proto

col Relations S

insd

R

X
S
ins

R

X
not

EOT S

insd

R

X
S
insd

R

X
not

delR

X
not

EOT S

deldR
X
S
del

R

X
not

EOT S

deldR
X
S
deld

R

X
not

insR

X
not

EOT Control S

running
S
ins

R

X
not

R

X
S
running
S
delR
X
R
X
S
EOT
S
BOT

not running

S
EOT
S
running
not

ab

rt
S
not

running

Pro

cedures S

X
BOT
S
X
S
committed
X
S
X
S
X

N

EOT

not ab

rt

S

ab
rted
X
S
X
S
X

N

EOT

ab

rt
LID

SLIDE 11 Statelog Compilation and T ermination

Statelog

p rograms P can b e directly translated into logic p rograms with function symb

ls

S

RX
S
insPY

QXY

RS
X
insPS
Y

QS

XY

stateS

Denition
f

states state

stateS
X
S
X
stateS
stateS
aliveS
if

nitely many states a re created b y P

E

D B

E

B Event Base then P terminates

aliveS
BOTS
aliveS
runningS
not

EOTS

In

every frame F

there

is at most

ne

state F n st MP

E

D B

E

B

j
EOTF

n

LID

SLIDE 12 Example revisited p ro c hireESalDept O empsalemp dep Mempsalemp dep initial new empESalDept

checksalDept
alw

a ys ab

rt

ab

rtedchecksalDept

endp ro c p ro c new empESalDept M empsalemp dep initial insempsalESal

insemp

depEDept

endp

ro c p ro c checksalDept Oemp depempsal initial ab

rt

avgDeptAmt not Amt endp ro c

LID

SLIDE 13 Statelog Conclusion and Outlo

k

Statelog

decla

rative semantics fo r active rules and up dates

classes
f

terminating active rules

increased

exp ressive p

w

er checking and enfo rcing

f

static and dynamic ICs

Integration

and fo rmalization

f

nested transactions i Logic p rogramming semantics ii Kripk est yle semantics fo rmalizes the conceptual mo del

f

nested transactions in Statelog Outlo

k
Exp

ressive p

w

er with nested transactions

Goalo

riented evaluation

Implementation
Reasoning

ab

ut

transactions P

E

D B

E

B

j
I

C fo r all E B and all E D B reachable via P

LID

SLIDE 14 Statelog Kripk e Structures Def A Statelog Kripk e structure

ver

signature

is

a tuple K

G
A

Q R S

U
M

P

where

G is a set

f

states A actions is a set

f

p ro cedure names Q S

G
A
U
G
a

re t w

ma

rk ed accessibilit y relations b et w een states rep resenting the p ro cedurecall resp return relation Qg

x

g

the

rst state

f

the subtransaction induced b y

x

is g

S

g

x
g
g
is

the nal state

f

the subtransaction induced b y

x

in g

results
f

subtransactions a re communicated via S R

G
G

mo dels the temp

ral

successo r relation U is the universe

f

elements M maps states to rsto rder interp retations P is a function which maps every g

G

to a set

f

lo cal rules the rules visible in g

LID

SLIDE 15 Statelog Kripk e Structures

R

R R R R R R R R Q Q S S

LID

SLIDE 16 Statelog Kripk e Structures Theo rem Adequacy

EDB

relations a re changed exactly via requests

Every

state contains all requests contributed b y subtransactions

IDB

relations a re derived lo cally b y userdened rules

Requests

a re derived b y userdened rules

r

contributed b y subtransactions

In

all states the p roto col relations contain all nonrevok ed changes

f

the co rre sp

nding

subtransactions

LID