Object Type XMLType
Oracle9i follows this approach and introduces a new object type XMLType. The main purpose of XMLType is to encapsulate the CLOB storage and to provide XPath-based methods to ease the handling of XML documents. XMLType can be used like any other Oracle type in tables. XMLType provides several methods for processing XML documents STATIC createXML xml VARCHAR CLOB MEMBER getClobVal RETURN CLOB MEMBER getStringVal RETURN VARCHAR MEMBER getNumberVal RETURN NUMBER MEMBER isFragment RETURN NUMBER The...
Chapter A Generic Architecture for Storing XML Documents in a Relational
Richard Edwards graduated with a Ph.D. from Leeds University in 1995 and spent 4 years in industry as a software developer, specializing in relational databases, GUI development, OLAP, and data warehousing. In 1999 he returned to academia, taking a post in the School of Education at the University of Wales, Bangor UWB , where he codeveloped the Electronic Village a DfES-funded groupware system for U.K. and French schools which showcased at the BBC's Tomorrow's World Live event in 2000. He now...
The SQL Function SYSXMLGen
SYS_XMLGen is a standalone function that assumes one select expression, the result of which is then converted into XML. The function converts a value into an XMLType object similar to XSU that is, the structure is defined by a canonical mapping. Again, object views can be used to affect the structure of the XML document. But in contrast to XSU, only one expression is allowed in the query. SELECT SYS_XMLGen Lastname FROM Customer WHERE CNo gt 1 The result of this query consists of one XMLType...
Bulkloading
Neither Updategrams nor the OpenXML mechanism previously described is well suited to load large amounts of XML data into the database since they both require the whole XML document to be loaded into memory before they perform the insertion of the data. Bulkload is provided as a COM object that allows loading large amounts of XML data via an annotated schema into either an existing database or after creating the relational schema implied by the annotated schema. Transacted and nontransacted load...
Prerequisites
In order to use the contains function, some prerequisites are necessary, making the handling complicated. Generally, contains requires a text index for the column that contains text documents. It is just then that indexing takes place that is, that terms are correctly found in documents. Furthermore, the within operator needs a text section, called section group, which can be defined and added to an index. The most comfortable way for XML is to use a path_section_group, because it takes into...