1. SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic R. Adamus,K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture R. Adamus, K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture 1 Wrapping Relational Data Structures to Object- Oriented Databases in the Data Grid Architecture COMPUTER ENGINEERING DEPARTMENT TECHNICAL UNIVERSITY OF LODZ, POLAND SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic Radoslaw Adamus, Kamil Kuliberda, Jacek Wislicki, Kazimierz Subieta

2. SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic R. Adamus,K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture R. Adamus, K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture 2 Wrappers Introduction problem started in late 80-ties – first approaches concerning object-oriented wrappers built on top of the relational database; problem started in late 80-ties – first approaches concerning object-oriented wrappers built on top of the relational database; motivation for the wrapper – business data virtual integration; motivation for the wrapper – business data virtual integration; transparency – grid needs this; transparency – grid needs this; data optimization – utilization of optimization mechanisms in both data models; data optimization – utilization of optimization mechanisms in both data models; used techologies – Stack-Based Approach (SBA), M0 model, SBQL, Updateable Views used techologies – Stack-Based Approach (SBA), M0 model, SBQL, Updateable Views ”Data Grid” conception integrates business information;integrates business information; data-intensive grid – simply data grid;data-intensive grid – simply data grid; simplification of data access;simplification of data access; common grid data model for virtualization of local schemata – canonical data model;common grid data model for virtualization of local schemata – canonical data model; implementation is based on ODRA database engineimplementation is based on ODRA database engine

3. SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic R. Adamus,K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture R. Adamus, K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture 3 Data Grid architecture Contributory schema Global client 1 Global infrastructures (trust, transactions, indexing, workflow, enhanced web services) Global schema Integration schema Global client 2 Global client 3 Global virtual object and service store (implemented through global views) Wrapper + Contributory views Local schema Local server 1 Wrapper + Contributory views Local schema Local server 2 Grid designer

4. SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic R. Adamus,K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture R. Adamus, K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture 4 Object-to-relational wrapper it combines exploiting SBQL query engine and SQL query engine; it combines exploiting SBQL query engine and SQL query engine; externally data structure is designed according to the object-oriented model externally data structure is designed according to the object-oriented model and business intention of global schema – front-end; internally relational structures are presented as M0 model – back-end; internally relational structures are presented as M0 model – back-end; updateable object views define mapping between front-end and updateable object views define mapping between front-end and back-end, B into F for querying, F onto B for updating; back-end, B into F for querying, F onto B for updating; the wrapper utilizes three major optimization methods for back-end side: the wrapper utilizes three major optimization methods for back-end side: - rewriting (for instance pushing selections before joins), - rewriting (for instance pushing selections before joins), - indices (i.e. internal auxiliary structures for fast access), - indices (i.e. internal auxiliary structures for fast access), - fast joins (e.g. hash joins); - fast joins (e.g. hash joins); during optimization, SBQL syntactic query tree is first modified from business to M0 model; wrapper obtain much larger tree, but addressing a primitive object database that is 1:1 mapped wrapper obtain much larger tree, but addressing a primitive object database that is 1:1 mapped to corresponding relational database; in resulting tree wrapper is looking for some patterns that can be mapped in resulting tree wrapper is looking for some patterns that can be mapped to SQL and which enforce SQL optimization methods; example; if we know that RDBMS has an index for Name of Person we are looking for pattern example; if we know that RDBMS has an index for Name of Person we are looking for pattern Person where Name = “Doe”; Person where Name = “Doe”; then we substitute above pattern for dynamic SQL statement: then we substitute above pattern for dynamic SQL statement: exec_immediately(select * from Person where Name = “Doe”); exec_immediately(select * from Person where Name = “Doe”) ;

5. SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic R. Adamus,K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture R. Adamus, K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture 5 Wrapper architecture SBQL front-end query Parser front-end SBQL query tree External wrapper (updatable views + query modification) back-end SBQL query tree Rewriting query optimizer Business model (object oriented) M0 representation of relational model Internal wrapper (convertion of parts of the tree to SQL exec_immediately) Info on indices and fast joins SBQL interpreter Dynamic SQL (ODBC, JDBC, ADO,...) RDBMS Relational model

6. SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic R. Adamus,K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture R. Adamus, K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture 6 Conclusions, future work presented wrapper architecture enables building generic solutions allowing presentation of data stored in various relational resources as object-oriented models presented wrapper architecture enables building generic solutions allowing presentation of data stored in various relational resources as object-oriented models these models are visible at the top level of the grid and accessing the data with object query language; these models are visible at the top level of the grid and accessing the data with object query language; presented optimization process assumes correct relational-to-object model transformation (with no loss of database logic) presented optimization process assumes correct relational-to-object model transformation (with no loss of database logic) allow on accessibility of the relational model optimization information such as indices and/or primary-foreign key relations; allow on accessibility of the relational model optimization information such as indices and/or primary-foreign key relations; the method is currently being implemented as a part of our new project ODRA devoted to Web and grid applications the method is currently being implemented as a part of our new project ODRA devoted to Web and grid applications; currently, based on presented conception, our research concerns object-to-semistructured wrapper exploiting native optimization mechanisms for querying semistructured data (e.g. Lore DBMS XML-based); currently, based on presented conception, our research concerns object-to-semistructured wrapper exploiting native optimization mechanisms for querying semistructured data (e.g. Lore DBMS XML-based);

7. SOFSEM-SRF 2006, January 21-26, Merin, Czech Republic R. Adamus,K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture R. Adamus, K. Kuliberda, J. Wislicki, K. Subieta Wrapping Relational Data Structures to Object-Oriented Databases in the Data Grid Architecture 7 Thank you for your attention!