|
|
(68 intermediate revisions by the same user not shown) |
Line 1: |
Line 1: |
− | <div style="float:right;border:1px solid #000000;padding:5px;max-width:500px;">__TOC__</div>
| + | For the current version, see: |
− | ==EclipseLink DBWS Overview==
| + | '''[http://www.eclipse.org/eclipselink/documentation/2.4/dbws/toc.htm Developing Persistence Architectures Using EclipseLink Database Web Services, Release 2.4]''' |
− | <onlyinclude>
| + | |
− | The goal of EclipseLink DBWS is to enable simple and efficient access to relational database artifacts via a Web service, providing Java EE-compliant client-neutral access to the database without having to write Java code. EclipseLink DBWS extends EclipseLink's core capabilities while leveraging existing ORM and OXM components.
| + | |
| | | |
− | EclipseLink DBWS has two parts: a design-time tooling component (<tt>DBWSBuilder</tt>) and a runtime provider component that takes a service descriptor (along with related deployment artifacts) and realizes it as a JAX-WS 2.0 Web service. The runtime provider uses EclipseLink to bridge between the database and the XML SOAP Messages used by Web service clients.
| + | For EclispeLink DBWS Overview, see http://www.eclipse.org/eclipselink/documentation/2.4/dbws/overview.htm |
| | | |
− | An EclipseLink DBWS service may be comprised of any number of <b>operations</b> of which there are 4 types:
| + | [[Category:DBWS]] |
− | # <b>insert</b> - inserts into the database persistent entities described by an XML document.
| + | |
− | # <b>update</b> - updates database persistent entities described by an XML document.
| + | |
− | # <b>delete</b> - removes from the database persistent entities described by an XML document.
| + | |
− | # <b>query</b> - retrieves from the database persistent entities described by an XML document. <br>Selection criteria for Query operations can be specified by:
| + | |
− | #* custom <tt>SQL SELECT</tt> statement
| + | |
− | #* Stored Procedure invocation
| + | |
− | #* EclipseLink Named Query (that can use the complete range of EclipseLink ORM Expression Framework APIs)
| + | |
− | | + | |
− | The XML documents used by an <b>operation</b> conform to an XML Schema Definition (<tt>.xsd</tt> file).
| + | |
− | | + | |
− | ===XML-to-Relational Mapping (XRM)===
| + | |
− | EclipseLink's ORM and OXM features provides the basis for a powerful ''bridge'' between a database's relational structure(s) and XML's hierarchical structure.
| + | |
− | [[Image:XRRunTime.png]]
| + | |
− | | + | |
− | ===Configuration===
| + | |
− | A typical EclipseLink DBWS service is packaged in an archive (<tt>.jar</tt> or <tt>.war</tt> file) with a service descriptor file
| + | |
− | <tt><b>eclipselink-dbws.xml</b></tt> in the META-INF directory (or WEB-INF/classes/META-INF when packaged in a <tt>.war</tt> file).
| + | |
− | To bridge the relational database and XML worlds, an EclipseLink sessions.xml <tt><b>eclipselink-dbws-sessions.xml</b></tt> points
| + | |
− | to two Eclipse projects - one for the ORM side, the other for the OXM side. The service also requires an XML Schema Definition file
| + | |
− | <tt><b>eclipselink-dbws-schema.xsd</b></tt> which in conjunction with the OXM project, specifies how information from the database
| + | |
− | is to be 'shaped' into XML documents.
| + | |
− | | + | |
− | <source lang="text" enclose="div">
| + | |
− | root of archive
| + | |
− | {not all files displayed ...}
| + | |
− | \---META-INF
| + | |
− | | eclipselink-dbws.xml
| + | |
− | | eclipselink-dbws-sessions.xml -- name can be overriden by <sessions-file> entry in eclipselink-dbws.xml
| + | |
− | | eclipselink-dbws-or.xml
| + | |
− | | eclipselink-dbws-ox.xml
| + | |
− | | eclipselink-dbws-schema.xsd -- when deployed in a .war file, is located in a different directory
| + | |
− | </source>
| + | |
− | The EclipseLink DBWS service descriptor file <tt><b>eclipselink-dbws.xml</b></tt> is easy to read, with minimum required information
| + | |
− | and simple defaults for omitted fields, allowing for both auto-generation by tools or manual editing:
| + | |
− | * <b><name></b> of EclipseLink DBWS service
| + | |
− | * <b><sessions-file></b> name of sessions.xml file - if not present, then <tt><b>eclipselink-dbws-sessions.xml</b></tt> will be used
| + | |
− | * <b>operation</b> definitions (see the four types mentioned above)
| + | |
− | Example DBWS Service descriptor file
| + | |
− | <source lang="xml">
| + | |
− | <?xml version="1.0" encoding="UTF-8"?>
| + | |
− | <dbws
| + | |
− | xmlns:xsd="http://www.w3.org/2001/XMLSchema"
| + | |
− | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
| + | |
− | >
| + | |
− | <name>example</name>
| + | |
− | <sessions-file>example-dbws-sessions.xml</sessions-file>
| + | |
− | <query>
| + | |
− | <name>countEmployees
| + | |
− | <result>
| + | |
− | <type>xsd:int</type>
| + | |
− | </result>
| + | |
− | <sql><![CDATA[select count(*) from EMP]]></sql>
| + | |
− | </query>
| + | |
− | </dbws>
| + | |
− | </source>
| + | |
− | The [[EclipseLink_DBWS_Service_Descriptor_File_(ELUG)|EclipseLink DBWS service descriptor file is described in full in the User Guide]].
| + | |
− | | + | |
− | ===XML Schema Definition===
| + | |
− | The EclipseLink DBWS service schema file <tt><b>eclipselink-dbws-schema.xsd</b></tt> can be created by hand, or auto-generated by the
| + | |
− | design-time <tt>DBWSBuilder</tt> tool that derives XML element-tag names from Database metadata (column names, types, nullable, etc).
| + | |
− | | + | |
− | ====Simple XML Format (SXF)====
| + | |
− | The <tt>DBWSBuilder</tt> tool will not generate an XML Schema Definition when the information returned by a <b>query operation</b> has no pre-determined structure, such as:
| + | |
− | * a resultSet from a custom SQL <b>query operation</b>
| + | |
− | * the results from a Stored Procedure <b>query operation</b>
| + | |
− | * the row-count from an <b>update operation</b>
| + | |
− | In these cases, the EclipseLink DBWS runtime provider uses information only available at the time of query execution to build the XML
| + | |
− | document:
| + | |
− | <source lang="xml">
| + | |
− | {Element tag names are direct copies of table's column names}
| + | |
− | <?xml version = '1.0' encoding = 'UTF-8'?>
| + | |
− | <simple-xml-format>
| + | |
− | <simple-xml>
| + | |
− | <EMPNO>7788</EMPNO>
| + | |
− | <ENAME>SCOTT</ENAME>
| + | |
− | <JOB>ANALYST</JOB>
| + | |
− | <MGR>7566</MGR>
| + | |
− | <HIREDATE>1987-04-19T00:00:00.000-0400</HIREDATE>
| + | |
− | <SAL>3000</SAL>
| + | |
− | <DEPTNO>20</DEPTNO>
| + | |
− | </simple-xml>
| + | |
− | <simple-xml>
| + | |
− | <EMPNO>7369</EMPNO>
| + | |
− | <ENAME>SMITH</ENAME>
| + | |
− | <JOB>CLERK</JOB>
| + | |
− | <MGR>7902</MGR>
| + | |
− | <HIREDATE>1980-12-17T00:00:00.000-0400</HIREDATE>
| + | |
− | <SAL>800</SAL>
| + | |
− | <DEPTNO>20</DEPTNO>
| + | |
− | </simple-xml>
| + | |
− | </simple-xml-format>
| + | |
− | </source>
| + | |
− | These XML documents are 'dumb' as they cannot be validated against any pre-determined schema - or more accurately, only the following
| + | |
− | very <b>permissive</b> 'sequence-of-any' schema can validate such documents:
| + | |
− | <source lang="xml" border="1">
| + | |
− | <?xml version="1.0" encoding="UTF-8"?>
| + | |
− | <xsd:schema
| + | |
− | xmlns:xsd="http://www.w3.org/2001/XMLSchema"
| + | |
− | >
| + | |
− | <xsd:complexType name="simple-xml-format">
| + | |
− | <xsd:sequence>
| + | |
− | <xsd:any minOccurs="0"/>
| + | |
− | </xsd:sequence>
| + | |
− | </xsd:complexType>
| + | |
− | </xsd:schema>
| + | |
− | </source>
| + | |
− | The element tags <tt><b>simple-xml-format</b></tt> and <tt><b>simple-xml</b></tt> can be customized by setting the appropriate properties
| + | |
− | on an <tt><b>operation</b></tt>.
| + | |
− | </onlyinclude>
| + | |
− | ----
| + | |
− | [[Category: Release 1.1]]
| + | |
− | [[Category: DBWS]] | + | |