不成功：在休眠/JPA/HSQLDB 独立版中更改表 XXX 丢弃约束 YYY

java hibernate jpa hsqldb in-memory

2022-09-01 01:46:45

我正在尝试使用内存中的HSQL数据库运行一些Hibernate / JPA示例。我收到的错误消息如下：

13:54:21,427 ERROR SchemaExport:425 - HHH000389: Unsuccessful: alter table ReferringItem_map drop constraint FK5D4A98E0361647B8
13:54:21,427 ERROR SchemaExport:426 - user lacks privilege or object not found: PUBLIC.REFERRINGITEM_MAP
13:54:21,427 ERROR SchemaExport:425 - HHH000389: Unsuccessful: alter table ReferringItem_myCollection drop constraint FK75BA3266361647B8
13:54:21,427 ERROR SchemaExport:426 - user lacks privilege or object not found: PUBLIC.REFERRINGITEM_MYCOLLECTION
13:54:21,428 ERROR SchemaExport:425 - HHH000389: Unsuccessful: alter table ReferringItem_myList drop constraint FK6D37AA66361647B8
13:54:21,428 ERROR SchemaExport:426 - user lacks privilege or object not found: PUBLIC.REFERRINGITEM_MYLIST
13:54:21,428 ERROR SchemaExport:425 - HHH000389: Unsuccessful: alter table ReferringItem_mySet drop constraint FK3512699A361647B8
13:54:21,429 ERROR SchemaExport:426 - user lacks privilege or object not found: PUBLIC.REFERRINGITEM_MYSET

相应的类是：

@Entity
public class ReferringItem implements Serializable {

    @Id
    private long id;

    @ElementCollection
    private Collection<AnEmbeddable> myCollection
        = new ArrayList<AnEmbeddable>();

    @ElementCollection(fetch=FetchType.EAGER)
    private Set<Long> mySet = new HashSet<Long>();

    @ElementCollection(targetClass=String.class)
    private List myList = new ArrayList();

    @ElementCollection
    private Map<String,AnEmbeddable> map
        = new HashMap<String,AnEmbeddable>();

    public ReferringItem() { }

    // Setters & Getters

}

可嵌入的为：

@Embeddable
public class AnEmbeddable implements Serializable {

    private String s;

    public AnEmbeddable() { }

    public String getS() {
        return s;
    }

    public void setS(String s) {
        this.s = s;
    }

}

我：persistence.xml

<persistence 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" version="2.0">

    <persistence-unit name="JPA" transaction-type="RESOURCE_LOCAL">

        <provider>org.hibernate.ejb.HibernatePersistence</provider>

        <class>com.jverstry.jpa.AuthorizedTypes.AuthorizedTypes</class>
        <class>com.jverstry.jpa.AuthorizedTypes.OtherEntity</class>
        <class>com.jverstry.jpa.AuthorizedTypes.SomeEmbeddable</class>

        <properties>
            <property name="javax.persistence.jdbc.driver" value="org.hsqldb.jdbcDriver"/>
            <property name="javax.persistence.jdbc.url" value="jdbc:hsqldb:mem:testdb"/>
            <property name="javax.persistence.jdbc.user" value="sa"/>
            <property name="javax.persistence.jdbc.password" value=""/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
        </properties>

    </persistence-unit>

</persistence>

我在冬眠和.4.1.5.FinalHSQLDB 2.2.8

有谁知道导致此问题的原因以及如何解决它？

答案 1

您可以忽略这些错误。和空数据库的组合（对于内存中总是如此）数据库会为其尝试删除的每个数据库对象生成这些值。原因是没有任何要删除的数据库对象 - DROP 语句是对空数据库执行的。create-drop

同样对于普通的永久数据库，这样的错误确实会出现，因为Hibernate在执行DROP语句之前没有弄清楚数据库中是否存在添加的对象还是新的。

答案 2

这个解决方案对我有用，而不是给出的其他解决方案。显然，里程各不相同。

这是我的确切错误：

HHH000389: Unsuccessful: alter table ... drop constraint FK_g1uebn6mqk9qiaw45vnacmyo2 if exists
Table "..." not found; SQL statement: ...

这是我的解决方案，覆盖H2方言：

package com.totaalsoftware.incidentmanager;

import org.hibernate.dialect.H2Dialect;

/**
 * Workaround.
 * 
 * @see https://hibernate.atlassian.net/browse/hhh-7002
 * 
 */
public class ImprovedH2Dialect extends H2Dialect {
    @Override
    public String getDropSequenceString(String sequenceName) {
        // Adding the "if exists" clause to avoid warnings
        return "drop sequence if exists " + sequenceName;
    }

    @Override
    public boolean dropConstraints() {
        // We don't need to drop constraints before dropping tables, that just
        // leads to error messages about missing tables when we don't have a
        // schema in the database
        return false;
    }
}