Chapter 12. Red Hat JBoss Data Virtualization VDB Sequencer

Teiid Designer is a visual tool that enables rapid, model-driven definition, integration, management and testing of Red Hat JBoss Data Virtualization without programming using the Red Hat JBoss Data Virtualization runtime engine. It is capable of modeling several different kinds of data structures, but the most common and widely-used are relational models that describe a relational database schema, including the catalogs/schemas, tables, views, columns, primary keys, foreign keys, indexes, procedures, procedure results, procedure results, and logical relationships. Teiid Designer can reverse-engineer a relational model from a JDBC relational database or DDL file. It can also define "virtual" models that are transformations of other models (where the transformations are defined in terms of SQL select, insert, update, and delete statements). These models can then be packaged into a virtual database, which can be deployed to a Red Hat JBoss Data Virtualization runtime engine.

Red Hat JBoss Data Virtualization is a high-performance database virtualization engine that allows JDBC and ODBC client applications access the virtual database as if it were a real database, using relational, XML, XQuery and procedural queries. Red Hat JBoss Data Virtualization dynamically (and in real-time) figures out how to answer the queries and operations issued by clients by efficiently accessing and manipulating the data inside the underlying data sources. The sophisticated engine is able to plan and optimize these operations, even when multiple heterogeneous relational and non-relational data sources must be accessed to obtain the required information.

The Red Hat JBoss Data Virtualization VDB sequencer parses the VDB archive files produced by the Teiid Designer, and extracts the structured relational data model described by each of the contained XMI files. This means that when VDB files are uploaded into a ModeShape repository, the sequencer writes to the repository all this virtual database and relational metadata contained in the VDB, where it can be queried and accessed by JCR , RESTful, and even JDBC clients.

The VdbSequencer has no properties for changing behavior.