with the property spring.jpa.hibernate.ddl-auto it's possible to auto generated table from entities.
What I need is that only some specific entities should be generated to tables in database an the rest of the entities do nothing.
It this possible ?
I guess this is your question here? https://discourse.hibernate.org/t/i-would-really-like-to-know-more-about-the-update/5455
Like I wrote there already, you shouldn't use hbm2ddl for anything other than development purposes. Use a proper schema management tool like Liquibase or Flyway.
As #pcsutar already commented, impl said SchemaFilterProvider
Related
I am using a Postgresql database with JPA / Hibernate. When I'm adding a constraint to a column, i.e. "nullable=false", the database column is not altered to reflect this. Deleting the table and rerunning the application does the job.
Can this be achieved with JPA/Hibernate - mechanisms only WITHOUT deleting entries or the table? Like "Try to alter the table and refuse to do so on inconsistent data"? In my application.properties, I've set
hibernate.hbm2ddl.auto=update
Any other setting seems to be deleting data and/or tables.
A working solution would be to run an ALTER TABLE script and adding a constraint annotation accordingly, but I'm not really fond of this.
It is impossible to add constraints to the existing table. Think wide about it - what if the data in the table is not satisfied with the constraint? You will get the whole application crash. So Hibernate not even trying to apply the potential harmful operation.
In general, there is the wrong way to manage database schema with hibernate. Auto-generation schema is appropriate for learning or MVP purposes but not for production. Also, SQL migration is a bad idea for many reasons. You should use a special tool for schema management: liquibase (better for me) or flywaydb
I am working on a project in Java (using Spring Boot, Thymeleaf, Hibernate, JPA, MySql). Every time I create a new Model Class, I have to create a table in the database or if I make any change in the Model class I have to alter the table by myself. Is there any way to avoid this database related stuff. For example I will make Model classes and declare their relationships my Database tables will be generated automatically. In future if I make any changes to my classes they will be applied to the database automatically without loosing any data.
Previously I worked on PHP, Laravel. There all I needed to do is 1) run command php artisan make:migration create_posts_table, 2) declare columns like $table->string('title');, $table->foreign('user_id')->references('id')->on('users'); and then 3) run command php artisan migrate. That's it. No SQL scripts needed. I was wondering if Java, Spring has something like this.
Sure you can do it.
Use spring.jpa.hibernate.ddl-auto=update in your application.properties.
You can also use more advanced tools like https://www.liquibase.org/
Ideal way
spring.jpa.hibernate.ddl-auto=none
In my opinion, the ideal way is to create one SQL file which will create the schema at the startup for us.
To let Spring Boot to create it for you
spring.jpa.hibernate.ddl-auto=update
spring.jpa.hibernate.ddl-auto= # DDL mode. This is actually a shortcut for the "hibernate.hbm2ddl.auto" property. Defaults to "create-drop" when using an embedded database and no schema manager was detected. Otherwise, defaults to "none".
Other Possible values: create, create-drop, validate
More Detailed Explanation
You can do migration using Flyway, it's similar to Laravel migration.
Add the dependency and put your migration SQL files to classpath:db/migration. Flyway will automatically check the sql files version and apply any pending migrations.
https://flywaydb.org/documentation/plugins/springboot
I want to test my program with an inmemory hsqldb. To create the table I use hibernate.hbm2ddl.auto=create
But I get an exception because the schemas, defined in the entity classes by annotations, are not created before the tables are created. Now I am searching for an opportunity to create the schemas before hibernate.hbm2ddl.auto runs. To remove the schemas is not an opportunity for me, because I need them for my program.
My problem is pretty much the same like this. The different is I do not use spring, so the solution does not work for me.
Assuming that you're using H2 database, you may provide init command to run with jdbc connection url. For example:
your.jdbc.url=jdbc:h2:mem:;DB_CLOSE_DELAY=-1;INIT=create schema IF NOT EXISTS your_schema
Unfortunately, the issue on hibernate jira is still unresolved https://hibernate.atlassian.net/browse/HHH-5665
Since Hibernate 5 there is a cleaner and more db-independent way, which also works with hsqldb. Add this configuration property:
hibernate.hbm2dll.create_namespaces=true
I'm using Hibernate (JPA2) hibernate.hbm2ddl.auto=update for test and hibernate.hbm2ddl.auto=validate for production.
What I want to do is, extending the generated schema with an additional table (that is not mapped to an entity) so that this table is generated for the tests and verify for production.
Is this possible, and how?
Yes, it's possible using "auxiliary database objects". I wrote a blog post on the topic because the documentation wasn't the greatest.
Edit: One other undocumented feature of Hibernate that I didn't mention in that blog: if you include a file named "import.sql" in the root of your classpath when you run a Hibernate schema export, it will also execute the statements in that file.
Write an SQL script to create the table. When you release up the environmental chain, run the SQL first to create the table in Prod. Then validate will be fine.
I have the need to be able to add additional columns to database tables in a Java JSF, JPA (JDO) application.
Eclipse Links supports this through the Flex Extension. Is there a similar Feature in other JPA Frameworks? I don't know about Hibernate. Also support in JDO would be interesting, as I would like to evaluate it one day.
Thanks for any advice.
Greets,
Andreas
In Hibernate you can set a property in the persistence XML named hibernate.hbm2ddl.auto with values (create | create-drop | update | validate) to let the provider know if you want to generate DDL.
Of course, this implies your configured connection has privileges to do DDL in the database in question (which is never a safe policy in a production database) :-)
In this another question there is more info
Hibernate hbm2ddl.auto possible values and what they do?
DataNucleus obviously supports such schema generation/update/delete features via persistence properties (jdo and jpa), and provides SchemaTool to allow it to be performed upfront, or to generate DDL for user editing before applying