Different databases have different settings for case sensitivity. The case sensitivity of the database is usually set through the collation that it uses.

The default embedded database (HSQL) in Confluence is a CASE SENSITIVE database. When you attempt to migrate this data to an external database that is set up with a case insensitive collation, you may experience problems.

You may encounter this error for example:

The data import process reported the duplicate error on the wrong object:
Import failed. (HibernateTemplate): data integrity violated by SQL ''; nested exception is java.sql.BatchUpdateException: Duplicate entry 'OSUser_user-11-confluence.prefs.email.notify' for key 1

or

2007-02-21 15:02:03,676 ERROR [sf.hibernate.util.JDBCExceptionReporter] logExceptions Violation of PRIMARY KEY constraint 'PK_OS_PROPERTYENTRY_619B8048'. Cannot insert duplicate key in object 'OS_PROPERTYENTRY'.
2007-02-21 15:02:03,692 ERROR [confluence.importexport.impl.ReverseDatabinder] endElement net.sf.hibernate.exception.ConstraintViolationException: could not insert: [bucket.user.propertyset.BucketPropertySetItem#bucket.user.propertyset.BucketPropertySetItem@d88630dc]
net.sf.hibernate.exception.ConstraintViolationException: could not insert: [bucket.user.propertyset.BucketPropertySetItem#bucket.user.propertyset.BucketPropertySetItem@d88630dc]
at net.sf.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:62)
at net.sf.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)