1. Technical University of Kaiserslautern Lehrgebiet Informationssysteme Muhammad Mainul Hossain Architectural Approaches of XDBMS Realization

2. TU Kaiserslautern LGIS Contents Comparisons Approaches Ideal Architecture XDBMS Strategies Discussion ROX Timber Natix XTC System RX eXist Tamino DB2 Oracle XMLDB SQL Server 2005 XML Research Commercial

3. TU Kaiserslautern LGIS Implementation Strategies RDBMS Table SQL Engine SQL XQuery Parser XQueryXML Rowset Shredding (XOR) RDBMS Table + XML in (B/C)LOB SQL Engine XQuery Co-Processor SQL + embedded XQuery Rowset + XML XML in CLOB/BLOB

4. Implementation Strategies TU Kaiserslautern LGIS Hybrid Native XML XDBMS XQuery SQL Parser SQLRowset XML Relational Over XML (ROX) RDBMS Table (XML Node in Column) SQLRowset SQL Engine Shared RDBMS XQueryXML XQuery Engine Native XML Storage XDBMS XQueryXML Pure Native

5. Ideal Architecture TU Kaiserslautern LGIS Support all proven-effective RDBMS features and techniques (e.g. scalability, reliability, usability, availability, concurrency, set-oriented access, procedural/declarative access) Optimized Indexing for node traversal, effective join and full-text search Transaction management and fine granular concurrency control Efficient query processing

6. Ideal Architecture TU Kaiserslautern LGIS LayerAbstractionObjects Data system L5 Nonprocedural Access Nodes, Documents, views L4 Navigational Access Sequences, (logical) Records, hierarchies, networks Access system L3Access Path Physical records, access path Storage system L2 Propagation Control Segments, pages L1File ManagementFiles, blocks Node-level support for arbitrary insertions and update Store and retrieve XML without any loss of fidelity Preferably XML schema support Support for XQuery, XPath, DOM, SAX should employ layered architecture...

7. TU Kaiserslautern LGIS Approaches: ROX Row Reply XML Node reference Lookup Request Query Optimizer Query Runtime XML Index SQL parse tree Optimized plan Relational result set XML Store XML Navigation Node Get Node XQuery Result DB2 XML Wrapper Fetch SQL on top of XQuery Engine DB2 XML Wrapper as interface to native store SQL-to- XQuery Translation Native Approach

8. TU Kaiserslautern LGIS Approaches: Timber Variant of range-based labeling scheme with start, end, level labels All processing instructions, comments etc. are ignored Pure Native Approach Used an algebra called TAX, later replaced by TLC Node not exactly same as DOM node Shore storage manager Query Parser Query Optimizer Metadata Manager Output API Query Evaluator Index Manager Data Manager Data Parser Storage Manager Data Loading Data Flow Retrieval Data Flow Parse Tree XML Data XQuery Stores XML schema Path, Value, full-text, Join indexes

9. Approaches: Natix TU Kaiserslautern LGIS Storage Layer Service Layer Binding Layer Java/C++ SAX Binding Apache mod_WebDAV Filesystem Driver Java/C++ DOM Binding Query Execution Transaction Management Object Manager Query Compiler Natix Engine Interface Storage Engine Pure Native Approach XML documents are mapped to tree-based logical data model Provides communication interface for all components Enables applications to bind to the Natix Engine Interface Full-text index, XASR index using a variant of range-based labeling scheme Supports Transaction management, ARIES protocol is extended for recovery Used an algebra named NAL Node not exactly same as DOM node Nodes are labeled with symbols from Σ Tags alphabet, leaves are labeled in addition with an arbitrarily long strings

10. Approaches: XTC TU Kaiserslautern LGIS Pure Native Approach Guarantees ACID properties Provides pages of fixed- length, each consists of variable-length records representing element/attribute nodes } Logical Data model is based on DOM A document store indexes all documents. Supports Path, Element, CAS indexes Each node in document store is mapped to a node handled by node manager Based on layered architecture Variant of Prefix-based labeling scheme based on Dewey Order called Stable Path Labeling Identifier (SPLID) is used

11. Approaches: XTC TU Kaiserslautern LGIS Pure Native Approach Based on layered architecture Lock manager transforms DOM into taDOM tree with 2 new nodes - AttributeRoot and String Hierarchical multi-granular locking with 8 lock modes Fine granular concurrency control for transaction isolation is supported through a Lock Manager

12. Approaches: Tamino TU Kaiserslautern LGIS X-Machine Data Store Kernel XML Data Store Meta Data Data Map X-Node X-Tension XML Engine HTTP XQuery/XPath, Tamino X-Query External Data Source Application XML Server Pure Native Commercial Approach Central component Stores schema information Supports value index, full-text index and structural index Transaction management with 2PC and hierarchical locking for concurrency control

13. Approaches: DB2 pureXML TU Kaiserslautern LGIS Query Evaluation SQL/XML Parser Hybrid SQL/XQuery Compiler XML Navigation XQuery Parser XML schema/DTD registered and stored in XML Schema Repository (XSR) Supports XML schema evolution Hybrid approach XML stored in native storage as XDM Single compiler for all query types Different parsers for SQL, Xuery, SQL/XML queries Value index, path index, full-text search XML data type used to store XML documents as column values.

14. Approaches: Oracle XML DB TU Kaiserslautern LGIS Direct HTTP Access Oracle Net Services Access WebDAV Access FTP Access Browser Application JDBC Application Desktop Tool FTP Tool Oracle Database Oracle XML DB Repository XMLType Tables and Views Oracle XML DB Hybrid approach Function-based index, bitmap index, full-text search with Oracle Text extract(), existsNode(), and extractValue() functions to query XML data, updateXML() to update XMLType Table or XMLType data type used to store XML documents Supports XML Schema registration and validation How much native is Oracle‘s native approach? 3 storage options - LOB-based, shredded decomposition into O-R tables, Hybrid Based on WebDAV

15. Approaches: SQL Server 2005 XML TU Kaiserslautern LGIS Hybrid approach FOR XML XML Parser Schema validatoin & Typing XML xml datatype modify() Relational Rowsets Open XML/ nodes() Node Table value() Primary Index PATH VALUE PROPERTY SQL Value query() query(), path(), exists(), nodes() functions takes XQuery expression to query data XML Data Modification Language (XML DML) to extend XQuery for insert, update XML schema registered and stored in XML Schema Collection, a new metadata Insert, delete, update XML Path, Value, Property and full-text indexing XML data type used to store XML documents as column values XML documents stored in native storage as XDM

16. TU Kaiserslautern Comparisons StorageIndexing Query Support API Support Transaction Processing XML Schema/ DTD ROXNativePath, Value SQL, XQuery, XPath Not Clear Not clear, based on underlying data engine XML Schema Timber Pure Native Value, Path, full- text, join index XQuery, XPath - Based on Shore data engine XML Schema Natix Pure Native Full text, XASR (kind of path) XQuery, XPath SAX, DOM Supported, extends ARIES for recovery, MGL protocol for CC Schema- less XTC Pure Native Document, Path, Element (inverted index), CAS index XQuery, XPath SAX, DOM Supported, several CC protocols and taDOM3+ protocol Schema- less System RX Native Value, Structured, Full- text XQuery, XPath, SQL, SQL/XM L SAX, DOM Supported, use of CC protocols from underlying RDBMS XML schema StorageIndexing Query Support API Support Transaction Processing XML Schema/DTD eXistPure Native Full-text, structure, value XQuery, XPath DOM, XML:D B Not supported Schema-less DB2 UDB Native, CLOB, Shredding Path, Value, Full- text XQuery, XPath, SQl, SQL/XM L DOM, SAX Supported, use of CC protocols from underlying RDBMS XML schema and DTD TaminoPure Native Value, Full- text, Structured XQuery, Tamino X-Query DOM, SAX Supported, user of hierarchical locking for CC XML schema and DTD Oracle 10g CLOB, Shredding Function- based (bundle of path and CAS indexes), Full-text XQuery, XPath, SQL, SQL/XML SAX, DOM Supported, use of CC protocols from underlying RDBMS XML schema SQL Server 2005 XML Native, CLOB, Shredding Path, Value, Property, Full-text XQuery, XPath, SQL, OpenXM L/FOR XML DOM Supported, use of CC protocols from underlying RDBMS XML schema LGIS

17. TU Kaiserslautern Discussion Timber, Natix use variants of range-based labeling scheme XTC uses prefix-based labeling scheme Pure native approach builds up XML document store and queries operate over that XML operations in hybrid databases are generally performed over relational tables Almost all XDBMS supports path, value and full-text indexes B- and B*-Tree for Storage and Indexing are most preferred data structures Most approaches use XML-schema or DTD XML-Schemas are stored in seperate storage as metadata and used for validation LGIS