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259 lines
8.3 KiB
Java
259 lines
8.3 KiB
Java
/*-
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* Copyright (C) 2002, 2017, Oracle and/or its affiliates. All rights reserved.
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*
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* This file was distributed by Oracle as part of a version of Oracle Berkeley
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* DB Java Edition made available at:
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*
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* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
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*
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* Please see the LICENSE file included in the top-level directory of the
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* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
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* license and additional information.
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*/
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package persist;
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import java.io.File;
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import java.util.HashSet;
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import java.util.Set;
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import com.sleepycat.je.DatabaseException;
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import com.sleepycat.je.Environment;
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import com.sleepycat.je.EnvironmentConfig;
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import com.sleepycat.persist.EntityCursor;
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import com.sleepycat.persist.EntityIndex;
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import com.sleepycat.persist.EntityStore;
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import com.sleepycat.persist.PrimaryIndex;
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import com.sleepycat.persist.SecondaryIndex;
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import com.sleepycat.persist.StoreConfig;
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import com.sleepycat.persist.model.Entity;
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import com.sleepycat.persist.model.Persistent;
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import com.sleepycat.persist.model.PrimaryKey;
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import com.sleepycat.persist.model.SecondaryKey;
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import static com.sleepycat.persist.model.DeleteAction.NULLIFY;
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import static com.sleepycat.persist.model.Relationship.ONE_TO_ONE;
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import static com.sleepycat.persist.model.Relationship.ONE_TO_MANY;
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import static com.sleepycat.persist.model.Relationship.MANY_TO_ONE;
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import static com.sleepycat.persist.model.Relationship.MANY_TO_MANY;
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public class PersonExample {
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/* An entity class. */
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@Entity
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static class Person {
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@PrimaryKey
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String ssn;
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String name;
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Address address;
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@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Person.class)
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String parentSsn;
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@SecondaryKey(relate=ONE_TO_MANY)
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Set<String> emailAddresses = new HashSet<String>();
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@SecondaryKey(relate=MANY_TO_MANY,
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relatedEntity=Employer.class,
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onRelatedEntityDelete=NULLIFY)
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Set<Long> employerIds = new HashSet<Long>();
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Person(String name, String ssn, String parentSsn) {
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this.name = name;
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this.ssn = ssn;
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this.parentSsn = parentSsn;
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}
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private Person() {} // For deserialization
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}
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/* Another entity class. */
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@Entity
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static class Employer {
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@PrimaryKey(sequence="ID")
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long id;
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@SecondaryKey(relate=ONE_TO_ONE)
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String name;
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Address address;
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Employer(String name) {
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this.name = name;
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}
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private Employer() {} // For deserialization
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}
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/* A persistent class used in other classes. */
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@Persistent
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static class Address {
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String street;
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String city;
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String state;
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int zipCode;
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private Address() {} // For deserialization
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}
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/* The data accessor class for the entity model. */
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static class PersonAccessor {
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/* Person accessors */
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PrimaryIndex<String,Person> personBySsn;
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SecondaryIndex<String,String,Person> personByParentSsn;
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SecondaryIndex<String,String,Person> personByEmailAddresses;
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SecondaryIndex<Long,String,Person> personByEmployerIds;
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/* Employer accessors */
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PrimaryIndex<Long,Employer> employerById;
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SecondaryIndex<String,Long,Employer> employerByName;
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/* Opens all primary and secondary indices. */
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public PersonAccessor(EntityStore store)
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throws DatabaseException {
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personBySsn = store.getPrimaryIndex(
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String.class, Person.class);
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personByParentSsn = store.getSecondaryIndex(
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personBySsn, String.class, "parentSsn");
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personByEmailAddresses = store.getSecondaryIndex(
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personBySsn, String.class, "emailAddresses");
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personByEmployerIds = store.getSecondaryIndex(
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personBySsn, Long.class, "employerIds");
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employerById = store.getPrimaryIndex(
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Long.class, Employer.class);
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employerByName = store.getSecondaryIndex(
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employerById, String.class, "name");
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}
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}
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public static void main(String[] args)
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throws DatabaseException {
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if (args.length != 2 || !"-h".equals(args[0])) {
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System.err.println
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("Usage: java " + PersonExample.class.getName() +
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" -h <envHome>");
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System.exit(2);
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}
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PersonExample example = new PersonExample(new File(args[1]));
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example.run();
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example.close();
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}
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private Environment env;
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private EntityStore store;
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private PersonAccessor dao;
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private PersonExample(File envHome)
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throws DatabaseException {
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/* Open a transactional Berkeley DB engine environment. */
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EnvironmentConfig envConfig = new EnvironmentConfig();
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envConfig.setAllowCreate(true);
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envConfig.setTransactional(true);
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env = new Environment(envHome, envConfig);
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/* Open a transactional entity store. */
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StoreConfig storeConfig = new StoreConfig();
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storeConfig.setAllowCreate(true);
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storeConfig.setTransactional(true);
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store = new EntityStore(env, "PersonStore", storeConfig);
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/* Initialize the data access object. */
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dao = new PersonAccessor(store);
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}
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private void run()
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throws DatabaseException {
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/*
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* Add a parent and two children using the Person primary index.
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* Specifying a non-null parentSsn adds the child Person to the
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* sub-index of children for that parent key.
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*/
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dao.personBySsn.put
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(new Person("Bob Smith", "111-11-1111", null));
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dao.personBySsn.put
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(new Person("Mary Smith", "333-33-3333", "111-11-1111"));
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dao.personBySsn.put
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(new Person("Jack Smith", "222-22-2222", "111-11-1111"));
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/* Print the children of a parent using a sub-index and a cursor. */
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EntityCursor<Person> children =
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dao.personByParentSsn.subIndex("111-11-1111").entities();
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try {
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for (Person child : children) {
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System.out.println(child.ssn + ' ' + child.name);
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}
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} finally {
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children.close();
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}
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/* Get Bob by primary key using the primary index. */
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Person bob = dao.personBySsn.get("111-11-1111");
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assert bob != null;
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/*
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* Create two employers if they do not already exist. Their primary
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* keys are assigned from a sequence.
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*/
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Employer gizmoInc = dao.employerByName.get("Gizmo Inc");
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if (gizmoInc == null) {
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gizmoInc = new Employer("Gizmo Inc");
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dao.employerById.put(gizmoInc);
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}
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Employer gadgetInc = dao.employerByName.get("Gadget Inc");
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if (gadgetInc == null) {
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gadgetInc = new Employer("Gadget Inc");
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dao.employerById.put(gadgetInc);
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}
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/* Bob has two jobs and two email addresses. */
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bob.employerIds.add(gizmoInc.id);
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bob.employerIds.add(gadgetInc.id);
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bob.emailAddresses.add("bob@bob.com");
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bob.emailAddresses.add("bob@gmail.com");
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/* Update Bob's record. */
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dao.personBySsn.put(bob);
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/* Bob can now be found by both email addresses. */
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bob = dao.personByEmailAddresses.get("bob@bob.com");
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assert bob != null;
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bob = dao.personByEmailAddresses.get("bob@gmail.com");
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assert bob != null;
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/* Bob can also be found as an employee of both employers. */
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EntityIndex<String,Person> employees;
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employees = dao.personByEmployerIds.subIndex(gizmoInc.id);
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assert employees.contains("111-11-1111");
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employees = dao.personByEmployerIds.subIndex(gadgetInc.id);
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assert employees.contains("111-11-1111");
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/*
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* When an employer is deleted, the onRelatedEntityDelete=NULLIFY for
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* the employerIds key causes the deleted ID to be removed from Bob's
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* employerIds.
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*/
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dao.employerById.delete(gizmoInc.id);
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bob = dao.personBySsn.get("111-11-1111");
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assert bob != null;
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assert !bob.employerIds.contains(gizmoInc.id);
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}
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private void close()
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throws DatabaseException {
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store.close();
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env.close();
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}
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}
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