Oracle® Containers for J2EE Enterprise JavaBeans Developer's Guide 10g (10.1.3.1.0) Part Number B28221-02 |
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Table 8-1 lists the TopLink EJB 3.0 JPA persistence provider query hints you can specify when you construct a JPA query, as Example 8-5 shows, or when you specify a JPA query using the @QueryHint
annotation, as Example 8-6 shows. When you set a hint, you can set the value using the corresponding public
static
final
field in the appropriate configuration class in oracle.toplink.essentials.config
as follows:
PessimisticLock
TopLinkQueryHints
HintValues
Note:
To access these classes, put the appropriate OC4J persistence JAR on your classpath (see "JPA Persistence JAR Files").Example 8-5 Specifying a TopLink JPA Query Hint
import oracle.toplink.essentials.config.HintValues; import oracle.toplink.essentials.config.TopLinkQueryHints; Customer customer = (Customer)entityMgr.createNamedQuery("findCustomerBySSN"). setParameter("SSN", "123-12-1234").setHint(TopLinkQueryHints.BIND_PARAMETERS, HintValues.PERSISTENCE_UNIT_DEFAULT).getSingleResult();
Example 8-6 Specifying a TopLink JPA Query Hint With @QueryHint
import oracle.toplink.essentials.config.HintValues; import oracle.toplink.essentials.config.TopLinkQueryHints; @Entity @NamedQuery( name="findAllEmployees", query="SELECT * FROM EMPLOYEE WHERE MGR=1" hints={ @QueryHint={name=TopLinkQueryHints.BIND_PARAMETERS, value=HintValues.PERSISTENCE_UNIT_DEFAULT} } ) public class Employee implements Serializable { ... }
Table 8-1 TopLink JPA Query Hints
Hint | Usage | Default |
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Control whether or not the query uses parameter binding. For more information, see "Parameterized SQL (Binding) and Prepared Statement Caching" in the Oracle TopLink Developer's Guide. Valid values:
Example: JPA Query API import oracle.toplink.essentials.config.HintValues; import oracle.toplink.essentials.config.TopLinkQueryHints; query.setHint(TopLinkQueryHints.BIND_PARAMETERS, HintValues.TRUE); Example: import oracle.toplink.essentials.config.HintValues; import oracle.toplink.essentials.config.TargetDatabase; @QueryHint(name=TopLinkQueryHints.BIND_PARAMETERS, value=HintValues.PERSISTENCE_UNIT_DEFAULT); |
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Control whether or not pessimistic locking is used. Valid values:
Example: JPA Query API import oracle.toplink.essentials.config.PessimisticLock; import oracle.toplink.essentials.config.TopLinkQueryHints; query.setHint(TopLinkQueryHints.PESSIMISTIC_LOCK, PessimisticLock.LockNoWait); Example: import oracle.toplink.essentials.config.PessimisticLock; import oracle.toplink.essentials.config.TopLinkQueryHints; @QueryHint(name=TopLinkQueryHints.PESSIMISTIC_LOCK, value=PessimisticLock.LockNoWait); |
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Control whether or not to update the TopLink session cache with objects that the query returns. Valid values:
Example: JPA Query API import oracle.toplink.essentials.config.HintValues; import oracle.toplink.essentials.config.TopLinkQueryHints; query.setHint(TopLinkQueryHints.REFRESH, HintValues.TRUE); Example: import oracle.toplink.essentials.config.HintValues; import oracle.toplink.essentials.config.TopLinkQueryHints; @QueryHint(name=TopLinkQueryHints.REFRESH, value=HintValues.TRUE); |
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