We began this chapter with the goal of mapping the following object model:
That goal has now been met. In the course of explaining JDOR's object-relational mapping metadata, we slowly built the requisite schema and mappings for the complete model. First, the database schema:
And finally, the complete JDOR mapping document:
Example 15.36. Full Mapping Document
<?xml version="1.0"?>
<orm>
<package name="org.mag">
<sequence name="ArticleSeq" datastore-sequence="ART_SEQ"/>
<class name="Magazine" table="MAG">
<version column="VERS" strategy="version-number"/>
<field name="isbn">
<column name="ISBN" jdbc-type="char" length="15"/>
</field>
<field name="title" column="TITLE"/>
<field name="price" column="PRICE"/>
<field name="copiesSold" column="COPIES"/>
<field name="coverArticle" column="COVER_ID" delete-action="restrict"/>
<field name="articles" table="MAG_ARGS">
<join delete-action="cascade">
<column name="MAG_ISBN" target="ISBN"/>
<column name="MAG_TITLE" target="TITLE"/>
</join>
<element column="ART_ID" delete-action="restrict"/>
</field>
<field name="publisher" column="PUB_ID" delete-action="restrict"/>
</class>
<class name="Article" table="ART">
<version column="UPD" strategy="date-time"/>
<field name="id" column="ID" sequence="ArticleSeq"/>
<field name="title" column="TITLE" unique="true"/>
<field name="content" column="CONTENT"/>
<field name="authors" table="ART_AUTHS">
<join column="ART_ID" delete-action="cascade"/>
<key column="LNAME"/>
<value column="AUTH_ID" delete-action="restrict"/>
</field>
<field name="subtitles" table="ART_SUBS">
<join column="ART_ID" delete-action="cascade"/>
<element column="SUBTITLE"/>
<order column="ORD"/>
</field>
</class>
</package>
<package name="org.mag.pub">
<sequence name="AuthorSeq" factory-class="Author$SequenceFactory"/>
<class name="Company" table="COMP">
<datastore-identity column="CID" strategy="autoassign"/>
<version strategy="none"/>
<field name="name" column="NAME" unique="true"/>
<field name="revenue" column="REV"/>
<field name="address">
<embedded null-indicator-column="STREET">
<field name="street" column="STREET"/>
<field name="city" column="CITY"/>
<field name="state">
<column name="STATE" jdbc-type="char" length="2"/>
</field>
<field name="zip" column="ZIP" indexed="true"/>
</embedded>
</field>
<field name="subscriptions" table="COMP_SUBS">
<join column="COMP_ID" delete-action="cascade"/>
<element column="SUB_ID" delete-action="restrict"/>
</field>
<field name="mags" mapped-by="publisher"/>
</class>
<class name="Author" table="AUTH">
<datastore-identity sequence="AuthorSeq">
<column name="AID" sql-type="INTEGER64"/>
</datastore-identity>
<inheritance>
<discriminator column="CLS" strategy="class-name"/>
</inheritance>
<version strategy="state-comparison"/>
<field name="firstName" column="FNAME"/>
<field name="lastName" column="LNAME" indexed="true"/>
<field name="address">
<embedded null-indicator-column="STREET">
<field name="street" column="STREET"/>
<field name="city" column="CITY"/>
<field name="state">
<column name="STATE" jdbc-type="char" length="2"/>
</field>
<field name="zip" column="ZIP" indexed="true"/>
</embedded>
</field>
</class>
</package>
<package name="org.mag.subscribe">
<sequence name="ContractSeq" strategy="transactional"/>
<class name="Contract">
<inheritance strategy="subclass-table"/>
</class>
<class name="Subscription" table="CNTRCT.SUB">
<inheritance>
<discriminator value="1">
<column name="TYPE" jdbc-type="tinyint"/>
</discriminator>
</inheritance>
<version column="VERS" strategy="version-number"/>
<field name="Contract.id" column="ID"/>
<field name="startDate" column="START"/>
<field name="payment" column="PAY"/>
<field name="items">
<element column="SUB_ID"/>
</field>
</class>
<class name="LifetimeSubscription">
<inheritance>
<discriminator value="2"/>
</inheritance>
<field name="eliteClub" column="ELITE"/>
</class>
<class name="TrialSubscription" table="CNTRCT.TRIAL_SUB">
<inheritance strategy="new-table">
<join column="ID" delete-action="restrict"/>
<discriminator value="3"/>
</inheritance>
<field name="endDate" column="END"/>
</class>
<class name="Subscription$LineItem" table="CNTRCT.LINE_ITEM">
<version column="VERS" strategy="version-number"/>
<field name="Contract.id" column="ID"/>
<field name="price" column="PRICE"/>
<field name="num" column="NUM" value-strategy="autoassign"/>
<field name="magazine" delete-action="restrict">
<column name="MAG_ISBN" target="ISBN"/>
<column name="MAG_TITLE" target="TITLE"/>
</field>
</class>
</package>
</orm>
Until now, we have focused on mapping metadata in the .orm
file format. As we mentioned at the beginning of this
chapter, however, you can integrate mapping metadata right into
your .jdo file instead. Here are the above
mappings integrated into our persistent class' JDO metadata:
Example 15.37. Integrated JDO Metadata Document
<?xml version="1.0"?>
<jdo>
<package name="org.mag">
<sequence name="ArticleSeq" datastore-sequence="ART_SEQ"/>
<class name="Magazine" objectid-class="Magazine$MagazineId" table="MAG">
<version column="VERS" strategy="version-number"/>
<field name="isbn" primary-key="true">
<column name="ISBN" jdbc-type="char" length="15"/>
</field>
<field name="title" column="TITLE" primary-key="true"/>
<field name="price" column="PRICE"/>
<field name="copiesSold" column="COPIES"/>
<field name="coverArticle" column="COVER_ID" delete-action="restrict"/>
<field name="articles" table="MAG_ARGS">
<collection element-type="Article" dependent-element="true"/>
<join delete-action="cascade">
<column name="MAG_ISBN" target="ISBN"/>
<column name="MAG_TITLE" target="TITLE"/>
</join>
<element column="ART_ID" delete-action="restrict"/>
</field>
<field name="publisher" column="PUB_ID" delete-action="restrict"/>
<fetch-group name="detail">
<field name="publisher" fetch-depth="0"/>
<field name="articles" fetch-depth="0"/>
</fetch-group>
</class>
<class name="Article" identity-type="application" detachable="true" table="ART">
<version column="UPD" strategy="date-time"/>
<field name="id" primary-key="true" column="ID" sequence="ArticleSeq"/>
<field name="title" column="TITLE" unique="true"/>
<field name="content" column="CONTENT"/>
<field name="authors" table="ART_AUTHS">
<map key-type="String" value-type="org.mag.pub.Author"/>
<join column="ART_ID" delete-action="cascade"/>
<key column="LNAME"/>
<value column="AUTH_ID" delete-action="restrict"/>
</field>
<field name="subtitles" table="ART_SUBS">
<collection element-type="String"/>
<join column="ART_ID" delete-action="cascade"/>
<element column="SUBTITLE"/>
<order column="ORD"/>
</field>
</class>
</package>
<package name="org.mag.pub">
<sequence name="AuthorSeq" factory-class="Author$SequenceFactory"/>
<class name="Company" table="COMP">
<datastore-identity column="CID" strategy="autoassign"/>
<version strategy="none"/>
<field name="name" column="NAME" unique="true"/>
<field name="revenue" column="REV"/>
<field name="address" embedded="true">
<embedded null-indicator-column="STREET">
<field name="street" column="STREET"/>
<field name="city" column="CITY"/>
<field name="state">
<column name="STATE" jdbc-type="char" length="2"/>
</field>
<field name="zip" column="ZIP" indexed="true"/>
</embedded>
</field>
<field name="subscriptions" table="COMP_SUBS">
<collection element-type="org.mag.subscribe.Subscription"/>
<join column="COMP_ID" delete-action="cascade"/>
<element column="SUB_ID" delete-action="restrict"/>
</field>
<field name="mags" mapped-by="publisher">
<collection element-type="org.mag.Magazine"/>
</field>
</class>
<class name="Author" table="AUTH">
<datastore-identity sequence="AuthorSeq">
<column name="AID" sql-type="INTEGER64"/>
</datastore-identity>
<inheritance>
<discriminator column="CLS" strategy="class-name"/>
</inheritance>
<version strategy="state-comparison"/>
<field name="firstName" column="FNAME"/>
<field name="lastName" column="LNAME" indexed="true"/>
<field name="address" embedded="true">
<embedded null-indicator-column="STREET">
<field name="street" column="STREET"/>
<field name="city" column="CITY"/>
<field name="state">
<column name="STATE" jdbc-type="char" length="2"/>
</field>
<field name="zip" column="ZIP" indexed="true"/>
</embedded>
</field>
</class>
<class name="Address" embedded-only="true"/>
</package>
<package name="org.mag.subscribe">
<sequence name="ContractSeq" strategy="transactional"/>
<class name="Contract" identity-type="application">
<inheritance strategy="subclass-table"/>
<field name="id" primary-key="true"/>
</class>
<class name="Subscription" detachable="true" table="CNTRCT.SUB">
<inheritance>
<discriminator value="1">
<column name="TYPE" jdbc-type="tinyint"/>
</discriminator>
</inheritance>
<version column="VERS" strategy="version-number"/>
<field name="Contract.id" column="ID"/>
<field name="startDate" column="START"/>
<field name="payment" column="PAY"/>
<field name="items">
<collection element-type="Subscription$LineItem" dependent-element="true"/>
<element column="SUB_ID"/>
<extension vendor-name="kodo" key="lock-group" value-"none"/>
</field>
</class>
<class name="LifetimeSubscription">
<inheritance>
<discriminator value="2"/>
</inheritance>
<field name="eliteClub" column="ELITE"/>
</class>
<class name="TrialSubscription" table="CNTRCT.TRIAL_SUB">
<inheritance strategy="new-table">
<join column="ID" delete-action="restrict"/>
<discriminator value="3"/>
</inheritance>
<field name="endDate" column="END"/>
</class>
<class name="Subscription$LineItem" table="CNTRCT.LINE_ITEM">
<version column="VERS" strategy="version-number"/>
<field name="Contract.id" column="ID"/>
<field name="price" column="PRICE"/>
<field name="num" column="NUM" value-strategy="autoassign"/>
<field name="magazine" delete-action="restrict">
<column name="MAG_ISBN" target="ISBN"/>
<column name="MAG_TITLE" target="TITLE"/>
</field>
</class>
</package>
</jdo>
