What are the JPA @Table annotation "catalog" and "schema" variables used for?

mysql hibernate jpa schema catalog
Sam Levin picture Sam Levin · Jun 25, 2012 · Viewed 24.3k times · Source

Why are these important, what effect do they have on the database at hand?

Isn't the "schema" already decided at that point, as it exists in the database?

What exactly is a "catalog"? What kind of variable/input is the JPA catalog field expecting? Also, same question for the "schema" field.

Answer

jpkrohling picture jpkrohling · Jun 25, 2012

Catalogs and schemas are "namespaces" that you define on the server side of the database. Some databases contains schemas, some contains catalogs, and some contains both. When logging in with a specific user, some databases defaults the schema/catalog to the user's namespace, causing the table to not be visible to other users, thus, causing the need to use a "common" namespace. So, depending on the database you are using to back your data, you might want to ignore those settings.

For MySQL, you might want to ignore those settings. This is because the "database" part of the JDBC URL (the one after the last slash) points to the database name, which is semantically identical to schema (for MySQL).

Related questions

Hibernate: Automatically creating/updating the db tables based on entity classes

I have the following entity class (in Groovy): import javax.persistence.Entity import javax.persistence.Id import javax.persistence.GeneratedValue import javax.persistence.GenerationType @Entity public class ServerNode { @Id @GeneratedValue(strategy = GenerationType.AUTO) Long id String firstName String lastName } and …

Read More
JPA mapping: "QuerySyntaxException: foobar is not mapped..."

I've been playing around with a very simple JPA example and am trying to tweak it to an existing database. But I can't get past this error. (Below.) It just has to be some simple thing I am not seeing. …

Read More
Catch duplicate entry Exception

How can i catch this Exception : com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '22-85' for key 'ID_CONTACT'

Read More