java 如何在运行时在 Hibernate 中创建数据库？
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How to create database in Hibernate at runtime?
提问by MAGx2
I'm using Hibernate tenancy and every time user logs I'm changing database to his username (SQLite). Sadly sometimes the database does not exists and I need to create it.
我正在使用 Hibernate 租赁，每次用户登录时，我都会将数据库更改为他的用户名 (SQLite)。可悲的是，有时数据库不存在，我需要创建它。
The problem is that I don't know how to create all tables in database at runtime.
问题是我不知道如何在运行时在数据库中创建所有表。
Normally Hibernete creates for me db with this:
通常，Hibernete 会为我创建数据库：
<property name="hibernate.hbm2ddl.auto">update</property>
采纳答案by Carsten
You can use the SchemaExport for this to export the entities you want to create in your newly created database right after you created the database. the basic steps are below. How you get the properties for your config does not really matter.
您可以为此使用 SchemaExport 来在创建数据库后立即导出要在新创建的数据库中创建的实体。基本步骤如下。如何获取配置的属性并不重要。
Configuration config = new Configuration();
config.addAnnotatedClass(Class1.class);
config.addAnnotatedClass(Class2.class);
config.addAnnotatedClass(Class3.class);
<set all hibernate properties/datasource here>
SchemaExport schema = new SchemaExport(config);
schema.create(true, true);
Javadocs are here: http://docs.jboss.org/hibernate/orm/3.3/api/org/hibernate/tool/hbm2ddl/SchemaExport.html
Javadocs 在这里：http: //docs.jboss.org/hibernate/orm/3.3/api/org/hibernate/tool/hbm2ddl/SchemaExport.html
For options of setting upt the configuration look here. http://docs.jboss.org/hibernate/orm/3.3/api/org/hibernate/cfg/Configuration.html
有关设置配置的选项，请查看此处。http://docs.jboss.org/hibernate/orm/3.3/api/org/hibernate/cfg/Configuration.html
Edit:I guess a remark that has to be added is that it is considered bad practice to let hibernate handle DB/SCHEMA/TABLE creation in a production environment. Depending on the needs and the viability it might be better practice to save prepared SQL statements for this, or even do it manualy by a DB admin. But since we are all lazy I guess thats not often going to happen. ;D
编辑：我想必须添加的一句话是，让休眠处理生产环境中的 DB/SCHEMA/TABLE 创建被认为是不好的做法。根据需要和可行性，为此保存准备好的 SQL 语句可能是更好的做法，或者甚至由数据库管理员手动执行。但由于我们都很懒惰，我想这不会经常发生。;D
回答by e2-e4
Did you try the value createinstead.
您是否尝试过该值create。
A value of create will create your tables at sessionFactory creation, and leave them intact.
A value of create-drop will create your tables, and then drop them when you close the sessionFactory.
create 值将在 sessionFactory 创建时创建您的表，并保持它们不变。
create-drop 的值将创建您的表，然后在您关闭 sessionFactory 时删除它们。
That would be
那将是
<property name="hibernate.hbm2ddl.auto">create</property>
More infornation hereand here
Or there could be a dialect problem
