hbm2ddl

问题 I couldn't find a reference on how to switch hbm2ddl off. 回答1: Just omitting hibernate.hbm2ddl.auto defaults to Hibernate not doing anything. From the reference documentation: 1.1.4. Hibernate configuration The hbm2ddl.auto option turns on automatic generation of database schemas directly into the database. This can also be turned off by removing the configuration option , or redirected to a file with the help of the SchemaExport Ant task. Setting hbm2ddl.auto to none (undocumented) might

问题 I\'m trying to update existing table with hbm2ddl.auto = update. There is several columns in several tables where database column definitions changes from declaration in entities. Like @Column(name=\"mycolumn\", nullable=false, length=10) private Long mycolumn; and \'mycolumn\' bigint(20) not null default 0 in MySQL. Why hbm2ddl doesn\'t update such things? And is it possible to force such update? I want to say hbm2ddl to remove default value of column and change length of type. 回答1:

问题 Is it okay to run Hibernate applications configured with hbm2ddl.auto=update to update the database schema in a production environment? 回答1: No, it's unsafe. Despite the best efforts of the Hibernate team, you simply cannot rely on automatic updates in production . Write your own patches, review them with DBA, test them, then apply them manually. Theoretically, if hbm2ddl update worked in development, it should work in production too. But in reality, it's not always the case. Even if it

问题 I really want to know more about the update, export and the values that could be given to hibernate.hbm2ddl.auto I need to know when to use the update and when not? And what is the alternative? These are changes that could happen over DB: new tables new columns in old tables columns deleted data type of a column changed a type of a column changed its attributes tables dropped values of a column changed In each case what is the best solution? 回答1: From the community documentation: hibernate