Concepts Guide
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This chapter provides an overview of the BEA Liquid Data for WebLogic architecture and describes the different roles for Liquid Data users. It includes the following sections:
This section describes the Liquid Data architecture and contains the following subsections:
The following diagram shows the components of Liquid Data. For a diagram showing Liquid Data and the rest of the WebLogic Platform, see Figure 2-5.
Figure 2-1 Liquid Data Components Architecture
This section describes the main components of Liquid Data:
The Liquid Data Server runs as an application in WebLogic Server. The Liquid Data Server processes query requests from Liquid Data client applications. Liquid Data queries are written in the W3C standard XQuery language. The Liquid Data server handles incoming query requests, and then the distributed query processor translates the XQuery into an optimized query plan and executes queries against the underlying data sources. The Liquid Data server then combines the results from the underlying data sources to form a single XML result, which is returned to the client application.
The Liquid Data repository is the central location for stored queries, data views, source and target schemas, XML data, web service descriptions (WSDL files), custom function libraries, stored procedures and other SQL queries, and delimited files. For more information, see Managing the Liquid Data Repository in the Liquid Data Administration Guide.
Data View Builder is a GUI tool for designing, generating, testing, and deploying Liquid Data queries. Data View Builder provides a drag-and-drop paradigm which allows query builders to easily combine data sources, functions, web services, and other query components together by connecting elements to each other and projecting the results onto a target schema. Data View Builder generates queries in the XQuery language and allows users to save queries to the Liquid Data repository. Once the queries are saved to the repository, client applications can run the queries (via a variety of interfaces), accessing the data in the underlying heterogeneous data sources.
Data View Builder generates queries in the XQuery language based on the mappings, conditions, and joins defined in the design view. It also allows query builders to run, modify, and deploy the generated queries to the Liquid Data repository. Data Architects need not know the intricacies of the XQuery language to use Data View Builder and can focus instead on the data they want to integrate.
You can use the Data View Builder to create and deploy data views, which are queries that can be used as a data sources for other queries. Data views provide a logical view of the data, abstracting all of the details of the underlying data sources from the application developer. Developers can then easily create queries for their applications without requiring any knowledge about the specific underlying systems. In this way, application developers, not just data architects, can directly access distributed, heterogeneous data sources. For more information about the Data View Builder, see Building Queries and Data Views.
The WebLogic Server Administration Console is a comprehensive, Web-based administration tool for configuring and monitoring WebLogic servers. Liquid Data extends the WebLogic Server Administration Console to provide additional tabs, accessible via a Liquid Data node, that are used to configure and manage Liquid Data servers deployed in the WebLogic Server environment.
Figure 2-3 Tabs in the Liquid Data Node in the Administration Console
System Administrators use the tabs on the Liquid Data node to configure access to data sources and custom functions, manage the server repository, configure query results caching, implement security, generate Web services, and so on. For more information, see the Liquid Data Administration Guide.
Liquid Data includes a Java Control Extension for WebLogic Workshop. The Liquid Data control provides access to Liquid Data queries directly through the WebLogic Workshop IDE. The Liquid Data control generates XMLBean classes which allow developers to easily access and manipulate the result set of the queries accessed from the control.
Developers can then use the Liquid Data Control in conjunction with other controls and features of WebLogic Workshop to develop complex applications. For example, developers can use the Liquid Data Control and NetUI to create web applications that access distributed data. Developers can also create service oriented applications where Liquid Data provides data integration services.
WebLogic Workshop, with its controls architecture, together with the Liquid Data Control provide a seamless developer experience for building portals, web services, and business processes.
The Liquid Data control appears with all of the other built-in and custom controls in WebLogic Workshop.
Figure 2-4 Liquid Data Control in WebLogic Workshop
For details about using WebLogic Workshop to develop Liquid Data applications, see the Liquid Data Application Developer's Guide.
Liquid Data provides an API (application programming interface) that allows client Java applications to submit queries to the Liquid Data for processing. Liquid Data supports three types of clients:
In addition to custom client applications, the Liquid Data Query API allows other BEA products—WebLogic Portal, WebLogic Workshop, WebLogic Web services, and the Business Process Management component of WebLogic Integration—to invoke Liquid Data queries transparently.
Liquid Data provides a set of standard functions to use when creating data views and queries. Application Developers can also define custom functions to extend the power and functionality of Liquid Data. Queries can invoke custom functions during query execution just as they can standard functions. For more information, see Creating Custom Functions in the Application Developer's Guide.
Liquid Data is part of the WebLogic Platform 8.1. It takes advantage of the advanced, enterprise-class capabilities of WebLogic Server to deliver scalable, reliable, and highly available distributed data access services. Liquid Data provides complementary functionality to WebLogic Integration, and allows you to use WebLogic Portal to add applications that use Liquid Data to display disparate data into your existing portal infrastructure. Liquid Data also includes a Java Control Extension for WebLogic Workshop, providing a strong integration with the WebLogic Workshop integrated development environment (IDE).
This section describes the Liquid Data architecture and how it fits in with the WebLogic Platform 8.1. The following sections are included.
The following diagram shows the components of the Liquid Data architecture and how Liquid Data fits in the WebLogic Platform architecture.
Figure 2-5 Liquid Data and WebLogic Platform 8.1 Architecture
Liquid Data is deployed as an enterprise application within WebLogic Server. It therefore takes advantage of all the services available to WebLogic Server, such as JDBC Connection Pools and Data Sources, scalability and clustering, and the full array of J2EE features and services. It operates seamlessly with other applications running in WebLogic Server.
The core of the Liquid Data server is a sophisticated distributed query processor that divides user requests for information into optimized sub-queries, which in turn are processed against many data sources. Liquid Data supports data aggregation from most enterprise data sources, including relational databases, web services, enterprise application and mainframe resources (through WebLogic Adapters) files such as XML files and delimited files, and to any other custom data source through custom functions.
For comprehensive information about BEA WebLogic Server, see the WebLogic Server documentation at the following URL:
http://download.oracle.com/docs/cd/E13222_01/wls/docs81/index.html
WebLogic Integration is a solution delivering application integration, business process management, and B2B integration functionality for the enterprise.
Complex business processes and application integration projects usually involve complex data lookups. Examples of these include enrichment of a incoming purchase order with related information from multiple enterprise data sources, delivering supporting information about a customer to a supervisor to help them make better decisions while approving a purchase order in a worklist, and so on.
Liquid Data simplifies complex data aggregation in integration projects. Through the Liquid Data control, developers can now perform an efficient, single-step lookup of distributed data instead of having to write complex workflows that embody the essence of a distributed query processor. Liquid Data provides essential data integration capabilities that, when used in conjunction with WebLogic Integration, reduce the cost and complexity of enterprise integration.
For comprehensive information about BEA WebLogic Integration, see the WebLogic Integration documentation at the following URL:
http://download.oracle.com/docs/cd/E13214_01/wli/docs81/index.html
For more information about Liquid Data and WebLogic Integration, see Invoking Queries in Business Process Manager Applications in the Application Developer's Guide and "Deploying Liquid Data in a WebLogic Integration Domain" in Deployment Tasks in the Liquid Data Deployment Guide.
Portals provide a single point of access to enterprise information, applications and processes, personalized to fit the role and needs of the end-user. Portals are also considered to be the "business face" to enterprise information. One of the most challenging aspects of providing a business face to enterprise information is the ability to access related data from distributed, heterogeneous data sources and delivering them to numerous portals and audiences.
Liquid Data provides a cost-effective data abstraction layer that reduces the cost, complexity and time-to-value of portal development. Liquid Data hides the complexity and specificity of underlying data sources and provides a simple API through which developers can access distributed data. Consequently, developers can focus on what information they need and leave the how to access and aggregate that information to Liquid Data. Through its repository and reusable views, Liquid Data also promotes reuse and consistency in how information is dealt with across various portal initiatives.
Developers can use the Liquid Data control to access distributed information and convert the results into personalized portlets in a single, seamless development environment—WebLogic Workshop. For more information, see Invoking Queries in BEA WebLogic Portal Applications in the Application Developer's Guide and "Deploying Liquid Data in a WebLogic Portal Domain" in Deployment Tasks in the Deployment Guide.
WebLogic Workshop is an IDE and development framework designed to simplify J2EE application development. WebLogic Workshop provides an abstraction model for enterprise resources through controls. Controls provide a simple, convenient mechanism by which to develop enterprise class applications. Liquid Data provides a control for use in the WebLogic Workshop development environment.
Enterprises looking to develop complex, service-oriented applications will find Workshop to be a convenient and cost effective development environment. Liquid Data is an integral part of any service-oriented architecture providing a virtual data access layer that hides the complexity and specificity of underlying data sources. Developers can now program to a simple API that enables the access and aggregation of data from multiple, heterogeneous data sources. The Liquid Data control generates an XMLBean interface to distributed data. This can be used in conjunction with other powerful features of Workshop including NetUI to easily deliver complex applications.
This section describes the roles, responsibilities, and resources for the following types of Liquid Data users:
Each type of user has different tasks and tools for using the Liquid Data technology.
Data Architects know about the desired business entities to be created and the data sources that are required. Data Architects tend to be subject matter experts and have a deep understanding of the data, underlying schema, and relationships across the various data sources. They create the data views and stored queries used by the Application Developers, using either the Data View Builder tool or creating hand-coded XQuery queries. For more information, see Building Queries and Data Views.
Application Developers create applications that use the data views and stored queries, created by the Data Architects, to access real-time information. Application Developers can access data views and stored queries using the following mechanisms:
Application Developers can also write custom functions in Java code to extend Liquid Data functionality.
For more information, see Application Developer's Guide.
System Administrators install, deploy, configure, and maintain the Liquid Data server. In addition to standard WebLogic Server administration tasks, an administrator uses the Liquid Data node in the Administration Console to perform the following kinds of tasks:
For more information, see the Liquid Data Administration Guide and Deployment Guide.
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