Just as the BEA WebLogic Application Server freed application developers from the tedium associated with managing multi-user applications across the Internet, BEA Aqualogic Data Services Platform allows data application developers to concentrate on developing and extending enterprise information without a need to directly program to the underlying physical data sources.
AquaLogic Data Services Platform takes advantage of emerging standards to enable you to create hierarchical, enterprise-wide data services which can be accessed by any Web-based application.
Specifically, data services enable you to:
Insulate integrated applications and processes from complexity of divergent data forms and potentially disconnected sources of enterprise data.
Manage the metadata information imported from disparate data sources.
Create data models showing the relationships between various data services.
Note:
AquaLogic Data Services Platform was originally named Liquid Data. Some artifacts of the original name remain in the product, installation path, and components.
Figure 1-1 BEA Integrated Development Environment
Data Services and the Enterprise
In modern enterprises data is generally readily available. While this has reduced that need to move physical data into data warehouses, data marts, data mines, or other costly replications of existing data structures, the problems of dynamic data integration, immediate secured access and update, data transformation, and data synchronization remain some of the most vexing challenges facing the IT world.
AquaLogic Data Services Platform provides a comprehensive approach to this challenge by:
Providing a unified means of importing metadata representing the structure of any data source using its Metadata Import wizard.
Allowing for the creation of hierarchical data structures from tradition column-row data.
Providing a query-driven interface to extend the physical model so data specialists can create powerful transformations of existing data and queries.
Automatically creating data models that introspect physical data structures (and their contents) in situ, normalizes representation of diverse data, and allow the representation of the relationship of physical and logical data.
Maintaining the accuracy of metadata through automated updates from the data source.
AquaLogic Data Services Platform can be used to create, refine, and validate logical data structures through a process of importing data sources, creating physical and logical models, and designing queries for use by applications in an infrastructure that provides for easy maintenance, while enhancing security and performance.
Through standardized Service Data Objects (SDO) technology, web-based applications can automatically read and update relational data. Through simple Java programs AquaLogic Data Services Platform update capabilities can be extended to support any logical data source.
For an overview of the AquaLogic Data Services Platform system, see the AquaLogic Data Services Platform Concepts Guide.
For detailed, hands-on tutorial illustrating many AquaLogic Data Services Platform features and techniques see the AquaLogic Data Services Platform Samples Tutorial.
Data Access Integration Architecture
In contemporary enterprise computing, data typically passes through multiple processing and storage layers. While enterprise data can easily be accessed, turning that data into useful information economically and efficiently, particularly updateable information, remains a difficult and high-maintenance task.
Figure 1-2 AquaLogic Data Services Platform Component Architecture
AquaLogic Data Services Platform approaches the problem of creating integration architectures by building logical data services around physical data sources and then allowing business logic to be added as part of easily maintained, graphically designed XML query functions (also called XQueries).
Using standard protocols such as JDBC, AquaLogic Data Services Platform automatically introspects data sources, creating physical data services and corresponding schemas that model a physical data source. Optional model diagrams capture relationships between relational data sources, such as primary and foreign keys.
Any WebLogic Workshop application can include AquaLogic Data Services Platform-based projects. And any application can access AquaLogic Data Services Platform queries — including update functions — through a mediator API or a AquaLogic Data Services Platform Control. In the case of relational data, updates can be performed automatically through Service Data Objects (SDO) (For details see Programming with Service Data Objects in the AquaLogic Data Services Platform Client Application Developer's Guide.)
AquaLogic Data Services Platform provides for the development of integrated queries within any WebLogic Workshop application. Each application can contain multiple AquaLogic Data Services Platform-based projects, as well as any other types of projects offered by WebLogic Workshop.
Figure 1-3 Sample Data Service
AquaLogic Data Services Platform Applications and Projects
AquaLogic Data Services Platform query and model development services are available through a AquaLogic Data Services Platform-based WebLogic Workshop project. After you have installed AquaLogic Data Services Platform (see the Installation Guide), you have two options:
Creating a AquaLogic Data Services Platform-based project within any WebLogic Workshop application: File New Project AquaLogic Data Services Platform Project
Creating a new AquaLogic Data Services Platform-based application: File New Application AquaLogic Data Services Platform Application
Services Available to a AquaLogic Data Services Platform-Based Project
A AquaLogic Data Services Platform-based project is comprised of a number of interrelated data services used in developing models and query functions. Service components are designed to enable rapid development, prototyping, and deployment of these services and functions in your applications.
Major services provided by the AquaLogic Data Services Platform platform are listed in Table 1-4.
Table 1-4 Survey of Major Services Provided by AquaLogic Data Services Platform
Service
Feature
Data Services and Data Modeling
Physical models
Logical models
Relationships
Read functions
Procedures
Navigation functions
Roles
Metadata Management
Browse metadata
Search metadata
Impact analysis
Auditing
Reports
Import Metadata
Relational, Web services, XML files, delimited files, Java
Update metadata
Query Management
Graphical query development
Testing
Plan analysis
Performance reporting
Auditing
Source editing
Caching
Security
Application Services
Mediator API
AquaLogic Data Services Platform control
JDBC
Service Data Objects (SDO)
Automatic read-write to relational sources
Custom update
XQuery Engine
Inverse functions
For more information on WebLogic Workshop applications and projects see Applications and Projects in WebLogic Workshop online documentation.
AquaLogic Data Services Platform: Roles and Responsibilities
Metadata Development. Using the AquaLogic Data Services Platform Metadata Import wizard, any team member can quickly create a set of physical data services from enterprise data sources.
Data Service Development. A data architect with knowledge of the relationships between enterprise data sources can then create data services based on physical and previously developed logical services.
Query Development. Once data services are created, any IT team member can create reusable query functions using the graphical XQuery Editor. The editor is directly tied to a Source View that facilitates code-based modifications to automatically-generated designs.
Application Development. Application designers can use data service query functions in their BEA WebLogic applications. Through Service Data Objects (SDO) and the Mediator API or a AquaLogic Data Services Platform control, applications can retrieve and update data, yet remaining insulated from the complexities of managing the underlying data interaction.
Metadata Management. Administrators, architects, and designers can use the Metadata Browser for real-time introspection of disparate data source metadata that has been developed through AquaLogic Data Services Platform.
AquaLogic Data Services Platform: Typical Development Process
The following steps summarize a typical AquaLogic Data Services Platform-based project development cycle.
Import metadata. Metadata can be obtained for any data source that is available through your local application or BEA WebLogic Server. This may include relational data, Web service data, delimited files (spreadsheets), custom Java functions, and XML files. See Obtaining Enterprise Metadata.
Create a data model. You can graphically build a data model that shows the relationships and cardinality between the data services you have selected (see Modeling Data Services for details). In the data model, you can also modify and extend relationships between various data services as well as their return type.
Develop data services. You can elaborate on existing physical data through queries that span multiple physical and/or logical data services (Designing Data Services. The built-in XQuery Editor (Working with the XQuery Editor) includes standard XQuery functions and language construct prototypes. Using the editor you can map source elements or transformations to a return type.
The Data Service Palette provides access to all data services available to your application. Queries and data service logic are maintained in a single, editable source file that is fully integrated with your data service (Working with XQuery Source).
Test your function. The data service functions you create can be tested at any time. You can select any query in the current data service, add a simple or complex parameter (if required), run the query, and see the results (Testing Query Functions and Viewing Query Plans). If you have appropriate permissions, you can also update source data through Test View.
Review the query plan. You can view the query plan prior to or after running your query. The query plan describes the generated statements used to retrieve and update data. Execution time statistics are also available (
Using Query Plan View on page 7-17).
Examples, Samples, and Tutorials
Samples and examples used in this book are based on the Sample Retail Application (RTLApp) that is included with AquaLogic Data Services Platform. See also the Sample Retail Application Overview in the AquaLogic Data Services Platform Installation Guide.
A number of examples of AquaLogic Data Services Platform technology can be found in the AquaLogic Data Services Platform Samples Tutorial. This tutorial is also based on RTLApp.
