Question

i want to know for now, Is it possible in hibernate to create database schema if schema does not exist otherwise update the schema if it is already exist and there are some modification in hbm file with some value for property hibernate.hbm2ddl.auto .

As per my understanding create value will always drop the previous schema and create the new schema ? update value will not create new schema, it will just update the schem if exist a based on hbm.xml. Right?

www.un.org/Depts/DGACM/index_spanish.htm 地雷计划是当地chem,而不是生产chem。

Answer 1

www.un.org/Depts/DGACM/index_french.htm 如果不存在新计划,将确实产生新的计划。

Answer 2

你不需要使用SchemaExport,你只能使用SchemaUpdate。它发挥了巨大作用,如果你愿意,你可以先审查 s。

你们确实需要建立数据库,或为此使用一些支架。之后:

import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaUpdate;

public static void updateDb(Configuration cfg, boolean printSqlToConsole, boolean commit)
{
    SchemaUpdate u = new SchemaUpdate(cfg);
    u.setFormat(printSqlToConsole);
    u.execute(printSqlToConsole, commit);
}

Note: that it can do notprocess knownd/changed areas, You need to take care of that. 但它可以处理新的领域。未绘制地图的领域被忽视。

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