Technical University of Kaiserslautern

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

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

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

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

5. Ideal Architecture 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 Efficient query processing Transaction management and fine granular concurrency control LGIS

6. Ideal Architecture Support for XQuery, XPath, DOM, SAX Node-level support for arbitrary insertions and update Store and retrieve XML without any loss of fidelity Preferably XML schema support should employ layered architecture... LGIS

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

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

9. Approaches: Natix Pure Native Approach Enables applications to bind to the Natix Engine Interface Java/C++ DOM Binding Java/C++ SAX Binding Apache mod_WebDAV Filesystem Driver Binding Layer Provides communication interface for all components Natix Engine Interface XML documents are mapped to tree-based logical data model Query Compiler Query Execution Transaction Management Object Manager Service Layer Node not exactly same as DOM node Storage Layer Storage Engine Nodes are labeled with symbols from ΣTagsalphabet, leaves are labeled in addition with an arbitrarily long strings 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 LGIS

10. Pure Native Approach Approaches: XTC Based on layered architecture 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 } 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 Variant of Prefix-based labeling scheme based on Dewey Order called Stable Path Labeling Identifier (SPLID) is used LGIS

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

12. XQuery/XPath, Tamino X-Query HTTP X-Machine XML Engine Data Store Kernel X-Node X-Tension Application External Data Source Meta Data XML Data Store Data Map XML Server Approaches: Tamino 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 LGIS

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

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

15. Approaches: SQL Server 2005 XML Hybrid approach XML documents stored in native storage as XDM XML XML Parser XML data type used to store XML documents as column values Schema validatoin & Typing Path, Value, Property and full-text indexing Open XML/ nodes() Relational Rowsets modify() xml datatype FOR XML Insert, delete, update XML Node Table PATH Primary Index query() value() VALUE SQL Value PROPERTY 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 LGIS

16. Comparisons LGIS

17. 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

18. Thank You !