Why Does My Derby Database Show a 'Schema Does Not Exist' Error After Creating Tables?

Persisting Derby Tables: Understanding the "Schema Does Not Exist" Error

Creating tables manually through the database development perspective in Eclipse is an efficient way to define your database structure. However, encountering the "Schema does not exist" error upon accessing these tables from code can be frustrating. The dilemma arises when you have to restart your project multiple times during testing and wonder if recreating tables with each connection is necessary.

Fortunately, understanding the underlying reasons for this error can lead to a solution that eliminates the need for constant table creation. Here are three common scenarios that can result in the "schema does not exist" error despite having already created tables:

1. Incorrect Database Connection: Ensure you are connecting to the intended database. If the Connection URL specifies "create=true," Derby may have created a new empty database instead of connecting to the one you expected.
2. In-Memory Database: By default, Derby employs an "in-memory" configuration, implying that the database contents vanish when it is closed or your application exits. If this is the case, recreating tables each time you retrieve data is necessary to maintain your database.
3. User-Specific Schema: When connecting to the database as a different user, the default schema name based on your user name is used unless you explicitly execute the SET SCHEMA statement. As a result, the tables created in one schema will not exist in the other schema, leading to the "schema does not exist" error.

The above is the detailed content of Why Does My Derby Database Show a 'Schema Does Not Exist' Error After Creating Tables?. For more information, please follow other related articles on the PHP Chinese website!