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POPersisting deep object graph with JPA without em.flush()
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  1. POPersisting deep object graph with JPA without em.flush()
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    copied!<p>I have following model:</p> <p><em>Report</em>, <em>ReportSection</em> and <em>ReportSectionProperty</em>.</p> <p><em>Report</em> has zero to many <em>ReportSections</em>, <em>ReportSection</em> has zero to many <em>ReportSectionPropert</em>-ies. This would qualifie as three levels deep object graph.</p> <p>I create new <em>Report</em>, then add some sections to it, then add some properties to it. When I try to persist <em>Report</em>, I get following error:</p> <pre><code>Caused by: org.apache.openjpa.lib.jdbc.ReportingSQLException: ERROR: insert or update on table "report_section" violates foreign key constraint "fk_report_section_report" Detail: Key (id_node)=(186) is not present in table "report". {prepstmnt 20859482 INSERT INTO core.report_section (index_section, name, report_section_type, id_node) VALUES (?, ?, ?, ?) [params=?, ?, ?, ?]} [code=0, state=23503]</code></pre> <p>So, OpenJPA is persisting object graph, but somehow it started from the middle. id_node 186 is indeed the next id of the Report table but, obviously that object is not saved when ReportSection is being saved.</p> <p>If I put em.persist(report) then em.flush() between each operation of adding sections or properties, everything works. Is this the way to go?</p> <p>If I don't add any properties to sections, persisting Report works, even without em.flush().</p> <p>I use OpenJPA 2.0.3 as JPA provider.</p> <hr> <p>Maybe some relevant parts of the code:</p> <p>Report.java</p> <pre><code>public class Report{ @OneToMany(targetEntity = ReportSection.class, cascade = CascadeType.ALL, mappedBy="report") private List reportSections; public void addReportSection(ReportSection section){ synchronized (this) { if (getReportSections() == null) reportSections = new ArrayList(); reportSections.add(section); section.setReport(this); } } }</code></pre> <p>ReportSection.java</p> <pre>public class ReportSection{ @ManyToOne @JoinColumn(name="id_node") private Report report; @OneToMany(targetEntity=ReportSectionProperty.class, cascade=CascadeType.ALL, mappedBy="reportSection") private List reportSectionProperties; public void setReport(Report report) { this.report = report; } public void addReportSectionProperty(ReportSectionProperty reportSectionProperty){ synchronized (this) { if (getReportSectionProperties() == null) reportSectionProperties = new ArrayList(); reportSectionProperties.add(reportSectionProperty); reportSectionProperty.setReportSection(this); } } }</pre> <p>ReportSectionProperty</p> <pre>public class ReportSectionProperty{ @ManyToOne(cascade=CascadeType.ALL) @JoinColumn(name="id_report_section") private ReportSection reportSection; public void setReportSection(ReportSection reportSection) { this.reportSection = reportSection; } }</pre>
 

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