Using JPQL for queries to an MS-Access database using UCanAccess driver

Question

When using

JPA 2.1
EclipseLink 2.5.2
UCanAccess 4.0.4

We have the problem that the tables will get named with quotes ". This is because the underlying implementation is not really aware what dialect to use resulting in one incompatible to MSAccess. This then results in e.g. table annotations like @Table(name = "\"EMPLOYEE\"").

To solve this we have to include in orm.xml:

...
    <persistence-unit-defaults>
        <delimited-identifiers />
    </persistence-unit-defaults>
...

Now plain queries will work, but the use of JPQL in named queries will fail because the resulting SQL query will quote all column names:

[EL Warning]: 2019-06-02 21:14:27.818--UnitOfWork(2144282958)--Thread(Thread[main,5,main])--Local Exception Stack: 
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::4.0.4 unexpected token: Personen
Error Code: -5581
Call: SELECT "PersonId", "EMail", "Ansprechpartner", "Briefanrede", "Fax", "Name", "Ort", "PLZ", "Sortierung", "Straße", "Telefon" FROM "Personen"
Query: ReadAllQuery(name="Personen.findAll" referenceClass=Personen sql="SELECT "PersonId", "EMail", "Ansprechpartner", "Briefanrede", "Fax", "Name", "Ort", "PLZ", "Sortierung", "Straße", "Telefon" FROM "Personen"")
    at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:340)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:682)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:558)
    at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall(AbstractSession.java:2002)
    at org.eclipse.persistence.sessions.server.ServerSession.executeCall(ServerSession.java:570)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:242)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:228)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeSelectCall(DatasourceCallQueryMechanism.java:299)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.selectAllRows(DatasourceCallQueryMechanism.java:694)
    at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRowsFromTable(ExpressionQueryMechanism.java:2738)
    at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRows(ExpressionQueryMechanism.java:2691)
    at org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:495)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1168)
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:899)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1127)
    at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:403)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1215)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2896)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1804)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1786)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1751)
    at org.eclipse.persistence.internal.jpa.QueryImpl.executeReadQuery(QueryImpl.java:258)
    at org.eclipse.persistence.internal.jpa.QueryImpl.getResultList(QueryImpl.java:469)
    at de.mebrach.jungebuehne.vorverkauf.PersonenService.loadAll(PersonenService.java:20)
    at Main.main(Main.java:20)
Caused by: net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::4.0.4 unexpected token: Personen

Why are you adding delimited-identifiers to ORM.xml if the delimited identifiers don't actually work on your database? — Chris
@Chris : Otherwise all tables will get quoted / have to be quoted. Which then results in e.g. table annotations like @Table(name = "\"EMPLOYEE\"") — Marvin Emil Brach

Marvin Emil Brach Marvin Emil Brach · Accepted Answer · 2019-06-02T19:21:01

Include a trget-database property in persistence.xml:

<property name="eclipselink.target-database" value="org.eclipse.persistence.platform.database.AccessPlatformDelimiterConfig"/>

Add a new class to the class path:

package org.eclipse.persistence.platform.database;

public class AccessPlatformDelimiterConfig extends AccessPlatform {

    private static final long serialVersionUID = 7034590043310425678L;

    public AccessPlatformDelimiterConfig() {
        super();
        this.tableQualifier = "";
        this.startDelimiter = "[";
        this.endDelimiter = "]";
    }
}

Using JPQL for queries to an MS-Access database using UCanAccess driver

1 Answers