JPA2:create-or-extend-tables没有使用新列扩展现有表

Question

我使用的是JPA2、Eclipselink。我正在尝试向现有的数据库和表添加一个新列。我在POJO类MyTable中添加了一个新字段。尽管具有create-or-extend-tables属性，但新列没有被添加。

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="idpersistance">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>

<class>com.id.service.db.pojo.AppTable</class>
<class>com.id.service.db.pojo.MyTable</class>

<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"></property>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:2705/mydb"></property>
<property name="javax.persistence.jdbc.user" value="user"></property>
<property name="javax.persistence.jdbc.password" value="password"></property>

<property name="eclipselink.ddl-generation" value="create-or-extend-tables" /> 
<property name="eclipselink.ddl-generation.output-mode" value="database" />
<property name="eclipselink.id-validation" value="NULL"></property>
<property name="eclipselink.logging.level" value="FINE"/>
<property name="javax.persistence.lock.timeout" value="1000"/>
<property name="eclipselink.target-database" value="MySQL"/>

</properties>

</persistence-unit>
</persistence>

 Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException
 Internal Exception: java.sql.SQLException: null,  message from server: "Unknown column 'newcol' in 'field list'"
 Error Code: 1054

 eclipselink.jar (2.5.2)
 javax.persistence_2.1.0.v201304241213.jar

更新：我已经调试到Eclipselink代码中，发现它没有试图生成新列，它在EntityManagerFactoryProvider类中的ExtendDefaultTables()方法处抛出一个错误，并表示表已经存在并从该方法返回。

如果我手动将DataSourceAccessor类的IncrementCallCount()方法中有一个名为UseExternalConnectionPooling的字段。然后成功生成新列。因为字段是false，所以Eclipselink没有触发extend。我不确定，如果这是正确的领域去。

Answer 1

Map<String, Object> x = new HashMap<>();
...
x.put("eclipselink.logging.level.sql", "FINE");
...
Persistence.createEntityManagerFactory("MyPersistenceUnit", x);

[EL Fine]: sql: 2015-11-11 16:24:14.042--ServerSession(667237426)--Connection(1844518545)--ALTER TABLE bm_picinfo ADD account BIGINT NOT NULL 
[EL Fine]: sql: 2015-11-11 16:24:14.066--ServerSession(667237426)--SELECT 1
[EL Warning]: 2015-11-11 16:24:14.092--ServerSession(667237426)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: ERROR: column "account" contains null values

在上面的示例中，新字段被定义为

   @ManyToOne(targetEntity = BmAccountE.class)
   @JoinColumn(name = "account", nullable = false, insertable = false, updatable = false)
   public BmAccountE account;

在本例中，删除nullable=false是解决方案。