A database-wide property always has persistence. That is, its value is stored in the database. Typically, it is in effect until you explicitly change the property or until you set a system-wide property with precedence over database-wide properties (see ).

To disable or turn off a database-wide property setting, set its value to null. This has the effect of removing the property from the list of database properties and restoring the system property setting, if there is one (and if derby.database.propertiesOnly has not been set; see ).

A system-wide property might have persistence, depending on how you set it. If you set it programmatically, it persists only for the duration of the JVM of the application that set it. If you set it in the derby.properties file, a property persists until:

• That value is changed and the system is rebooted
• The file is removed from the system and the system is rebooted
• The database is booted outside of that system