Indexing XML Data in RDBMS using ORDPATH

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Indexing

XML

Data

in

RDBMS

using

ORDPATH

Microsoft

Microsoft®® SQL Server 2005SQL Server 2005™™

Concepts

Concepts developeddeveloped byby::

Patrick

Patrick OO‘‘NeilNeil, Elizabeth , Elizabeth OO‘‘NeilNeil, ,

(University of Massachusetts Boston) (University of Massachusetts Boston)

Shankar

Shankar PalPal, Istvan , Istvan CseriCseri, Oliver , Oliver SeeligerSeeliger, Gideon Schaller, , Gideon Schaller, Leo

Leo GiakoumakisGiakoumakis, Vasili , Vasili ZolotovZolotov, Nigel , Nigel WestburyWestbury

(Microsoft Corporation) (Microsoft Corporation)

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5. Juli 2006 Stephan Müller 2

Nobody loves bad bugs. <FIGURE CAPTION=”Sample bug”/> </SECTION>

<TITLE> Tree Frogs </TITLE>

All right-thinking people

<BOLD> love </BOLD> tree frogs. </SECTION>

</BOOK>

XML Data Model

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5. Juli 2006 Stephan Müller 3 Book Figure Section Caption Bold ISBN Section

Title All right Frogs

Nobody Title

XML Document / Fragment - Properties:

XML Data Model Hierarchy Document Order: 1 < 2 < 3 < 4 < 5 < ….. < 11 < 12 8 1 3 2 4 5 6 7 9 10 11 12

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SQL with embedded XQuery and XPath:

SELECT id, xdoc.query(‘

for $s in

/BOOK[@ISBN=“1-55860-438-3“]//SECTION

return <topic> { data($s/TITLE) } </topic> ‘)

FROM docs;

SQL Command:

CREATE TABLE docs (

id INT PRIMARY KEY,

xdoc XML

);

XML Fragment as BLOB XML Fragment as BLOB 7 7 … … … … … … … … XML

XML DocumentDocument as BLOBas BLOB 2 2 XML Fragment as BLOB XML Fragment as BLOB 1 1 XDOC XDOC ID ID

Created docs Table:

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ORDPATH

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What

we

expect

from

a

labeling

scheme

:

►

Support

for

structural

fidelity

(

Hierarchy

+

Document

Order)

►

Support

for

efficient

structural

modifications

to

the

XML

tree

--

insert

sub

-

tree

--

delete

sub

-

tree

--

move

sub

-

tree

►

Support

for

high

-

performance

query

plans

for

native XML

queries

using

relational primitives

►

Independence of XML

schemas

typing

XML

instances

without relabeling !!!

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5. Juli 2006 Book Figure Bold Section ISBN Caption Section

Title _{All right} _Frogs Nobody Title 1 1.1 1.3.3 1.3 1.3.1 1.5 1.3.5 1.3.5.1 1.5.1 1.5.3 1.5.5 1.5.7

Example of an Initial Load

1.5.7 1.5.7 1.5.5 1.5.5 1.5.3 1.5.3 1.5.1 1.5.1 1.5 1.5 1.3.5.1 1.3.5.1 1.3.5 1.3.5 1.3.3 1.3.3 1.3.1 1.3.1 1.3 1.3 1.1 1.1 1 1 ORDPATH ORDPATH '

'treetreefrogsfrogs'' 4 ( 4 (ValueValue)) --' 'lovelove'' 1 (Element) 1 (Element) 7 (BOLD) 7 (BOLD) 'All

'All rightright--thinkingthinkingpeoplepeople''

4 (

4 (ValueValue))

--'

'TreeTreefrogsfrogs''

1 (Element) 1 (Element) 4 (TITLE) 4 (TITLE) Null Null 1 (Element) 1 (Element) 3 (SECTION) 3 (SECTION) 'Sample

'Sample bugbug''

2 (Attribute) 2 (Attribute) 6 (CAPTION) 6 (CAPTION) Null Null 1 (Element) 1 (Element) 5 (FIGURE) 5 (FIGURE) 'Nobody

'Nobody loveslovesbad bad bugsbugs''

4 ( 4 (ValueValue)) --'Bad Bugs' 'Bad Bugs' 1 (Element) 1 (Element) 4 (TITLE) 4 (TITLE) Null Null 1 (Element) 1 (Element) 3 (SECTION) 3 (SECTION) '1 '1--5586055860--438438--3'3' 2 (Attribute) 2 (Attribute) 2 (ISBN ) 2 (ISBN ) Null Null 1 (Element) 1 (Element) 1 (BOOK) 1 (BOOK) VALUE VALUE NODE_TYPE NODE_TYPE TAG TAG Document Order: 1 < 1.1 < 1.3 < 1.3.1 < … < 1.5.7 Hierarchy

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L

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1.5.3.-9.11

O O_K_K L L_K_K … … O O₁₁ L L₁₁ O O₀₀ L L₀₀

ORDPATH Example Value:

Li /Oi Pair Desgin:

0100101101010110001111111000011

ORDPATH bit pattern:

We need a prefix-free L

_i

encoding…

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1.5.3.-9.11

L₀= 3 O₀ = 1 L₁= 3 O₁= 5 L₂= 3 O₂= 3 L₃= 4 O₃= -9 L₄ = 4 O₄= 11 01 001 01 101 01 011 00011 1111 100 0011 0100101101010110001111111000011 (Figure 3.2a)

Using Li values from Figure 3.2a

ORDPATH bit pattern

Li /Oi Pair Design

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Advantages of

comparing

ORDPATH

Values

:

►

Determination of

ancestor

–

descendent

relationships

for

any

two

ORDPATHs

is

very

easy

.

►

Easy

determination

of

the

distance

between

two

ORDPATHs

.

►

Simple

bitstring

(

or

byte

-

by

-

byte

)

comparison

yields

document

order.

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Context Node

Descendants of a given Context Node

Book Figure Bold Section ISBN Caption Section

Title _{All right} _Frogs Nobody Title 1 1.1 1.3.3 1.3 1.3.1 1.5 1.3.5 1.3.5.1 1.5.1 1.5.3 1.5.5 1.5.7 ( cn = 1.3 )

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14

‚

‚treetreefrogsfrogs'' 4 ( 4 (ValueValue)) --1.5.7 1.5.7 ‚ ‚lovelove'' 1 (Element) 1 (Element) 7 (BOLD) 7 (BOLD) 1.5.5 1.5.5 ‚

‚All All rightright--thinkingthinkingpeoplepeople''

4 ( 4 (ValueValue)) --1.5.3 1.5.3 ‚

‚TreeTree frogsfrogs''

1 (Element) 1 (Element) 4 (TITLE) 4 (TITLE) 1.5.1 1.5.1 Null Null 1 (Element) 1 (Element) 3 (SECTION) 3 (SECTION) 1.5 1.5 'Sample

'Sample bugbug''

2 (Attribute) 2 (Attribute) 6 (CAPTION) 6 (CAPTION) 1.3.5.1 1.3.5.1 Null Null 1 (Element) 1 (Element) 5 (FIGURE) 5 (FIGURE) 1.3.5 1.3.5 'Nobody

'Nobody loveslovesbad bad bugsbugs'' 4 ( 4 (ValueValue)) --1.3.3 1.3.3 'Bad Bugs' 'Bad Bugs' 1 (Element) 1 (Element) 4 (TITLE) 4 (TITLE) 1.3.1 1.3.1 Null Null 1 (Element) 1 (Element) 3 (SECTION) 3 (SECTION) 1.3 1.3 '1 '1--5586055860--438438--3'3' 2 (Attribute) 2 (Attribute) 2 (ISBN ) 2 (ISBN ) 1.1 1.1 Null Null 1 (Element) 1 (Element) 1 (BOOK) 1 (BOOK) 1 1 VALUE VALUE NODE_TYPE NODE_TYPE TAG TAG ORDPATH ORDPATH SELECT Ordpath FROM infoset WHERE 1.3 < Ordpath (cn) AND 1.4 > Ordpath (cn+1)

Descendants of a given Context Node SQL Query:

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Arbitrary

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Rightmost / Leftmost Insertion:

Arbitrary Insertions Child4 3.5.-1 Parent Child1 Child2 3.5 3.5.1 3.5.3 Child3 3.5.5

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Careting in nodes between two existing nodes…

3.5.2.2.-1 3.5.2.2.1 3.5.2.2 3.5.2.3 3.5.2.1 3.5.2 3.5 3.5.3 3.5.1 Arbitrary Insertions

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5. Juli 2006 Stephan Müller 18 Parent Child1 Child2 3.5 3.5.1 3.5.3 Child3 3.5.2.1 Child4 3.5.2.3 Child5 3.5.2.2.1 Child6 3.5.2.2.-1 Arbitrary Insertions Careting in nodes between two existing nodes…

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Note:

►

Multiple

levels

of

carets

are

extremely

rare in

practice

.

Advantage:

►

Insertions

require

no

relabelings

of

old

nodes

…

We

avoid

updates

to

primary

key

values

which

would

involve

the

primary

index

and all

secondary

indexes

.

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ORDPATH

…

►

…

is

a

hierarchical

prefix

-

based

labeling

scheme

.

►

…

provides efficient access to

subtrees

.

►

…

provides all kinds of modifications.

►

…