DB2 Extenders
DB2 Extenders enhance the usability and functionality of the relational database manager system (RDMS) for nontraditional data types, such as documents, multimedia, or geographical data. Unlike traditional data types in which the data is separated into individual elements, these data types have more complex structures. They can be complete text documents or binary files stored in large objects (LOBs). They can be external files stored on a local file system referenced using DB2 Datalinks Manager. They also can be structured data types with multiple properties.
Traditional SQL is unaware of the document structure, language, format or properties of nontraditional data types. The RDMS has limited functionality to manage these types of data. Applications performing complex searches or data manipulation would often have to retrieve the entire document even if all the data was not needed. Code was written to parse the contents of the document to find the required information. This may result in slow performance and an increase in application complexity and development time. DB2 Extenders provide solutions to aid in the development of applications working with several nontraditional data types.
Several DB2 Extender products make up the DB2 Extenders family: Text Extender; Net Search Extender; XML Extender, Audio, Image, and Video (AIV) Extenders; and Spatial Extender. Each product is designed for a specific data type and usage scenario. Text Extender is used to provide advanced text search capabilities such as precise, linguistic, and fuzzy logic searches. Net Search provides fast, scalable fuzzy logic searches intended for use over the Internet. This version of Net Search Extender combines the functionality of both DB2 Text information Extender version 7.2 and DB2 Net Search Extender version 7.2. AIV Extenders provides functions that can be used to identify and manipulate multimedia data. XML Extender enables generation, decomposition, and XPath searches of XML documents. Spatial Extender is used to analyze spatial information about geographic features.
Each DB2 Extender product can be installed separately and has its own administration commands, APIs, and utilities. They integrate with the RDMS by creating UDTs, UDFs, and stored procedures. Applications can call these functions directly with SQL statements. They do not require special code or handling, which makes DB2 Extenders accessible to most programming languages.
Additional reference material, that exceeds the requirements for the 703 Application Development Certification exam is covered later in this book in Part 3. This section includes an overview of DB2 Extenders and a chapter on each DB2 Extender product with detailed product specifications, usage scenarios, functionality, and administration, as well as Web links to find more information.