EclipseLink/Examples/DBWS/DBWSBasicTable

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EclipseLink DBWS Service based on Database Table

The use-case for this example is the creation of a Web service that exposes a database table's CRUD (Create/Read(findByPK,findAll)/Update/Delete) lifecycle operations. This is supported for any table (or tables - patterns supporting '%' can be used for catalog, schema or table names) on any database where the JDBC driver reliably and accurately delivers the table's metadata via the JDBC metadata APIs (java.sql.DatabaseMetaData).

This example uses the DBWSBuilder utility to generate a DBWS XML schema - it is generated using very simple rules:

  • table name ==> translate any characters not supported by XML 1 ==> translate to_lowercase ==> add suffix 'Type' ==> top-level complex element type in .xsd file
  • column name ==> translate any characters not supported by XML 1 ==> translate to_lowercase ==> becomes <element-tag> name
    • All columns are expressed as elements
    • BLOB columns are automatically mapped to xsd:base64Binary
    • xsd:base64Binary elements can be included in-line to the XML document, or handled as binary attachments (SwaRef-style).

1 same algorithm documented as part of the SQL/X (a.k.a. SQL/XML:2003) specification

The EMP table from the Oracle scott database schema will be used for this example:

OWNER TABLE_NAME COLUMN_NAME DATA_TYPE DATA_LENGTH DATA_PRECISION DATA_SCALE NULLABLE
SCOTT EMP EMPNO NUMBER 22 4 0 N
SCOTT EMP ENAME VARCHAR2 10 (null) (null) Y
SCOTT EMP JOB VARCHAR2 9 (null) (null) Y
SCOTT EMP MGR NUMBER 22 4 0 Y
SCOTT EMP HIREDATE DATE 7 (null) (null) Y
SCOTT EMP SAL NUMBER 22 7 2 Y
SCOTT EMP COMM NUMBER 22 7 2 Y
SCOTT EMP DEPTNO NUMBER 22 2 0 Y

The DBWSBuilder utility requires a DBWS configuration file as input.

<?xml version="1.0" encoding="UTF-8"?>
<dbws-builder xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <properties>
    <property name="projectName">emp</property>
    ... database properties
  </properties>
  <table
   catalogPattern="%"
   tableNamePattern="EMP"
 />
</dbws-builder>
prompt > dbwsbuilder.cmd -builderFile dbws-builder.xml -stageDir output_directory -packageAs wls emp.war

where

  • dbws-builder.xml is the DBWS builder XML file above
  • output_directory is the output directory for the generated files
  • -packageAs specifies the platform on which the web service will be deployed

The generated eclipselink-dbws-schema.xsd file derives <element-tag> names from the Database table metadata:

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
 >
  <xsd:complexType name="empType">
    <xsd:sequence>
      <xsd:element name="empno" type="xsd:int" xsi:nil="false"/>
      <xsd:element name="ename" type="xsd:string" xsi:nil="true"/>
      <xsd:element name="job" type="xsd:string" xsi:nil="true"/>
      <xsd:element name="mgr" type="xsd:int" minOccurs="0" xsi:nil="true"/>
      <xsd:element name="hiredate" type="xsd:dateTime" xsi:nil="true"/>
      <xsd:element name="sal" type="xsd:decimal" xsi:nil="true"/>
      <xsd:element name="comm" type="xsd:int" minOccurs="0" xsi:nil="true"/>
      <xsd:element name="deptno" type="xsd:int" xsi:nil="true"/>
    </xsd:sequence>
  </xsd:complexType>
</xsd:schema>

Generated EclipseLink DBWS service descriptor

One can see the CRUD operations in the generated EclipseLink DBWS service descriptor eclipselink-dbws.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<dbws xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:ns1="urn:emp" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <name>emp</name>
   <sessions-file>eclipselink-dbws-sessions.xml</sessions-file>
   <update>
      <name>update_empType</name>
      <parameter>
         <name>theInstance</name>
         <type>ns1:empType</type>
      </parameter>
   </update>
   <insert>
      <name>create_empType</name>
      <parameter>
         <name>theInstance</name>
         <type>ns1:empType</type>
      </parameter>
   </insert>
   <query>
      <name>findByPrimaryKey_empType</name>
      <parameter>
         <name>id</name>
         <type>xsd:decimal</type>
      </parameter>
      <result>
         <type>ns1:empType</type>
      </result>
      <named-query>
         <name>findByPrimaryKey</name>
         <descriptor>empType</descriptor>
      </named-query>
   </query>
   <delete>
      <name>delete_empType</name>
      <parameter>
         <name>theInstance</name>
         <type>ns1:empType</type>
      </parameter>
   </delete>
   <query>
      <name>findAll_empType</name>
      <result isCollection="true">
         <type>ns1:empType</type>
      </result>
      <named-query>
         <name>findAll</name>
         <descriptor>empType</descriptor>
      </named-query>
   </query>
</dbws>

SOAP Messaging

The following SOAP Message invokes the <findAll_empType> operation for the emp DBWS service:

<?xml version="1.0" encoding="UTF-8"?>