SqueakSave
An Automatic Object-Relational Mapping Framework
Thomas Kowark
Robert Hirschfeld
Michael Haupt
Software Architecture Group
Hasso-Plattner-Institut Potsdam
www.hpi.uni-potsdam.de/swa
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Outline
• motivation
• basic usage
• framework architecture
• performance
• summary & outlook
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 2
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Available Persistence Approaches
• image storing
• object databases
• (object-)relational persistence
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 3
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
SqueakSave – Project Goals
• automatic mapping deduction
• simplistic API
• seamless integration into existing applications
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 4
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Guiding Example
ual Paradigm for UML Community Edition [not for commercial use]
User +blog 1 Blog
-email : string -title : string
-username : string -lastUpdate : dateTime
-password : string +administeredBlogs 0..*
0..* +followers
1
0..* +blogPosts
BlogPost
1 -title : string
Author -text : string
1
1
0..* +comments
Comment
Admin -author : string
1..* -title : string
-text : string
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 5
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
API – Configuration
• configuration based on naming conventions
SqsConfig subclass: #BlogExampleSqsConfig
instanceVariableNames: ''
classVariableNames: ''
poolDictionaries: ''
category: 'BlogExample'
BlogExampleSqsConfig
class>>#connectionSpecification
^ SqsMySQLConnectionSpecification
user: 'admin'
password: 'password'
database: 'blog_example_db'
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 6
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
API – Basic Operations
author := Author new
password: 'password';
username: 'testuser';
email: 'user@example.org'.
author blog: (Blog new title: 'My Blog').
author save.
...
author destroy.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 7
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
API – Queries
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
(SqsSearch for: Author) select: [:anAuthor |
anAuthor blog blogPosts size > 10 ]
(SqsSearch for: Blog) anySatisfy: [:aBlog |
aBlog blogPosts noneSatisfy: [:aBlogPost |
aBlogPost comments isEmpty ] ]
(SqsSearch for: Blog) findByTitle: 'testblog'
(SqsSearch for: Comment)
findByAuthor: 'author' andTitle: 'comment'.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 8
lundi 31 août 2009

or commercial use]
SqueakSave: An Automatic Object-Relational Mapping Framework
Class
class currentClass
1 1
SqueakSave – Architecture
instVarValue
SqsBase 0..* SqsConnection
SqsProxy
SqsConnectionManager
+classInfo SqsClassInfo 1
1
+session SqsSession 1 <<use>>
1
dbAdapter 1
SqsDatabaseAdapter
ler SqsDescriptionHandler
1 <<use>>
0..*
0..1 connection
uctureHandler SqsTableStructureHandler SqsDatabaseConnection
1
ure 4.1: Overview of SqueakSave System Classes.
me into the separate sub words and connects them with an underscore. A
me’, for example, is thereby converted to the column name ‘user name’.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 9
vide31simple compatibility with most other O/R mappers for dynamic
lundi août 2009

or commercial use]
SqueakSave: An Automatic Object-Relational Mapping Framework
Class
class currentClass
1 1
SqueakSave – Architecture
instVarValue
SqsBase 0..* anObject save SqsConnection
SqsProxy
SqsConnectionManager
+classInfo SqsClassInfo 1
1
+session SqsSession 1 <<use>>
1
dbAdapter 1
SqsDatabaseAdapter
ler SqsDescriptionHandler
1 <<use>>
0..*
0..1 connection
uctureHandler SqsTableStructureHandler SqsDatabaseConnection
1
ure 4.1: Overview of SqueakSave System Classes.
me into the separate sub words and connects them with an underscore. A
me’, for example, is thereby converted to the column name ‘user name’.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 9
vide31simple compatibility with most other O/R mappers for dynamic
lundi août 2009

or commercial use]
SqueakSave: An Automatic Object-Relational Mapping Framework
Class
class currentClass
1 1
SqueakSave – Architecture
instVarValue
SqsBase 0..* SqsConnection
SqsProxy
SqsConnectionManager
+classInfo SqsClassInfo 1
1
SqsSession <<use>>
+session
Creation 1or fetching of
1
unique SqsStorage dbAdapter 1
ler SqsDescriptionHandler wrapper instance SqsDatabaseAdapter
1 <<use>>
0..*
0..1 connection
uctureHandler SqsTableStructureHandler SqsDatabaseConnection
1
ure 4.1: Overview of SqueakSave System Classes.
me into the separate sub words and connects them with an underscore. A
me’, for example, is thereby converted to the column name ‘user name’.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 9
vide31simple compatibility with most other O/R mappers for dynamic
lundi août 2009

or commercial use]
SqueakSave: An Automatic Object-Relational Mapping Framework
Class
class currentClass
1 1
SqueakSave – Architecture
instVarValue
SqsBase 0..* SqsConnection
SqsProxy
SqsConnectionManager
+classInfo SqsClassInfo 1
1
+session SqsSession 1 <<use>>
1
dbAdapter 1
SqsDatabaseAdapter
ler SqsDescriptionHandler
1 <<use>>
0..*
0..1 connection
uctureHandler SqsTableStructureHandler SqsDatabaseConnection
1 Creation or update of
mapping descriptions
ure 4.1: Overview of SqueakSave System Classes.
me into the separate sub words and connects them with an underscore. A
me’, for example, is thereby converted to the column name ‘user name’.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 9
vide31simple compatibility with most other O/R mappers for dynamic
lundi août 2009

or commercial use]
SqueakSave: An Automatic Object-Relational Mapping Framework
Class
class currentClass
1 1
SqueakSave – Architecture
instVarValue
SqsBase 0..* SqsConnection
SqsProxy
SqsConnectionManager
+classInfo SqsClassInfo 1
1
+session SqsSession 1 <<use>>
1
dbAdapter 1
SqsDatabaseAdapter
ler SqsDescriptionHandler
1 <<use>>
0..*
0..1 connection
uctureHandler SqsTableStructureHandler SqsDatabaseConnection
1
ure 4.1: Overview of SqueakSave System Classes.
Calculation of changes to
me into the separatedatabase and connects them with an underscore. A
the relational sub words
schema
me’, for example, is thereby converted to the column name ‘user name’.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 9
vide31simple compatibility with most other O/R mappers for dynamic
lundi août 2009

or commercial use]
SqueakSave: An Automatic Object-Relational Mapping Framework
Class
class currentClass
1 1
SqueakSave – Architecture
instVarValue
SqsBase 0..* SqsConnection
SqsProxy
SqsConnectionManager
+classInfo SqsClassInfo 1
1
+session SqsSession 1 <<use>>
1 Connection pooling
dbAdapter 1
SqsDatabaseAdapter
ler SqsDescriptionHandler
1 <<use>>
0..*
0..1 connection
uctureHandler SqsTableStructureHandler SqsDatabaseConnection
1
ure 4.1: Overview of SqueakSave System Classes.
me into the separate sub words and connects them with an underscore. A
me’, for example, is thereby converted to the column name ‘user name’.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 9
vide31simple compatibility with most other O/R mappers for dynamic
lundi août 2009

or commercial use]
SqueakSave: An Automatic Object-Relational Mapping Framework
Class
class currentClass
1 1
SqueakSave – Architecture
instVarValue
SqsBase 0..* SqsConnection
SqsProxy
SqsConnectionManager
+classInfo SqsClassInfo 1
1
+session SqsSession 1 <<use>>
1
dbAdapter 1
SqsDatabaseAdapter
ler SqsDescriptionHandler
1 <<use>>
0..*
0..1 connection
uctureHandler SqsTableStructureHandler SqsDatabaseConnection
Schema update and
1
object insertion or update
ure 4.1: Overview of SqueakSave System Classes.
me into the separate sub words and connects them with an underscore. A
me’, for example, is thereby converted to the column name ‘user name’.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 9
vide31simple compatibility with most other O/R mappers for dynamic
lundi août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Query Analysis
• SQL statement generation through block execution
with placeholder objects
• one placeholder class per ‘simple type’,
SqsQueryObject and SqsQueryCollection for
complex cases
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 10
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Query Analysis
• SQL statement generation through block execution
with placeholder objects
• one placeholder class per ‘simple type’,
SqsQueryObject and SqsQueryCollection for
complex cases
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
queryObject := SqsQueryObject new
depictedClass: User.
result := aBlock value: queryObject.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 10
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Query Analysis
• SQL statement generation through block execution
with placeholder objects
• one placeholder class per ‘simple type’,
SqsQueryObject and SqsQueryCollection for
complex cases
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
The query object does not know what #username
does, but generates the SQL to scope to the
respective column.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 10
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Query Analysis
• SQL statement generation through block execution
with placeholder objects
• one placeholder class per ‘simple type’,
SqsQueryObject and SqsQueryCollection for
complex cases
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
WHERE users.username
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 10
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Query Analysis
• SQL statement generation through block execution
with placeholder objects
• one placeholder class per ‘simple type’,
SqsQueryObject and SqsQueryCollection for
complex cases
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
The result of the first call is an SqsQueryString.
It knows how to map the #= to SQL properly.
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 10
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Query Analysis
• SQL statement generation through block execution
with placeholder objects
• one placeholder class per ‘simple type’,
SqsQueryObject and SqsQueryCollection for
complex cases
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
WHERE users.username =
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 10
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Query Analysis
• SQL statement generation through block execution
with placeholder objects
• one placeholder class per ‘simple type’,
SqsQueryObject and SqsQueryCollection for
complex cases
(SqsSearch for: User) detect: [:aUser |
aUser username = 'testuser']
WHERE users.username = ‘testuser’
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 10
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Evaluation
• evaluation based on OO7 benchmark
– CAD application data structure
– complex object model with many cyclic dependencies
• set of queries with increasing complexity
• number of traversals of an object graph
• comparison with GLORP
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 11
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Evaluation – Query Performance
• approx. 20% slower than GLORP
• two exceptions
– caching mechanism (10x slower)
(SqsSearch for: SqsAtomicPart) detect:
[:ap | ap oid = id].
– query creation with joins (1/3x faster)
(SqsSearch for: SqsBaseAssembly) select: [:ba |
ba unsharedParts anySatisfy: [:part |
part document = id ]].
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 12
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Evaluation – Traversal Performance
Traversal 1 Traversal 2a
6s
5s
3s
2s
0s
SqueakSave GLORP SqueakSave GLORP
Traversal 2b Traversal 2c
24s
18s
– missing eager loading – minimal intrusion into object
(n+1 queries problem) 12s models (only collection proxies)
6s
0s
SqueakSave GLORP SqueakSave GLORP
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 13
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Summary and Outlook
• simple usage & setup
– integration into existing applications almost seamless
• automatic deduction of database structures
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 14
lundi 31 août 2009

SqueakSave: An Automatic Object-Relational Mapping Framework
Summary and Outlook
• simple usage & setup
– integration into existing applications almost seamless
• automatic deduction of database structures
• possible extensions
– SqueakDBX usage
– eager loading
– performance optimizations
Thomas Kowark, Robert Hirschfeld, Michael Haupt (www.hpi.uni-potsdam.de/swa) 2009 14
lundi 31 août 2009