java 如何在jpa持久性xml文件中自动创建表？
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how to automatic create table in jpa persistence xml file?
提问by Ummer Iqbal
I am using eclipse IDE.I also try following two .but failed..when i manually create table in my mysql database then my complete program run fine... I want create table automatic with respect to entity class.
我正在使用 Eclipse IDE。我也尝试以下两个。
<property name="hibernate.hbm2ddl.auto" value="create"/>
<property name="hibernate.hbm2ddl.auto">update</property>
here my persistence file:
这是我的持久性文件：
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="JpaTest2" transaction-type="RESOURCE_LOCAL">
<class>com.jpa.Employee</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/hibernate"/>
<property name="javax.persistence.jdbc.user" value="umar"/>
<property name="javax.persistence.jdbc.password" value="umar"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="hibernate.show_sql" value="true"/>
<property name="hibernate.format_sql" value="true"/>
</properties>
</persistence-unit>
回答by Neil Stockton
Dont use Hibernate specific options. JPA 2.1 provides
不要使用 Hibernate 特定的选项。JPA 2.1 提供
javax.persistence.schema-generation.database.action
that can be set to "create", "drop", "drop-and-create", "none". That way you keep your code JPA implementation independent
可以设置为“ create”、“ drop”、“ drop-and-create”、“ none”。这样你就可以让你的代码 JPA 实现独立
回答by Peter L
Check your entity. Did you miss @Table annotation? The exception clearly says that the table is missing 'hibernate.employee':
检查您的实体。您是否错过了@Table 注释？异常清楚地表明该表丢失'hibernate.employee'：
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'hibernate.employee' doesn't exist at ...
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'hibernate.employee' doesn't exist at ...
If you defined a naming strategy that prepends all tables with hibernate., then make sure that the tables are created in MySql.
如果您定义了一个命名策略，该策略将所有表添加到休眠状态。，然后确保表是在 MySql 中创建的。
