When you specify user authorizations, Derby verifies
that a user has been granted permission to access a system, database, object,
or SQL action.
There are two types of user authorization in Derby,
connection authorization and SQL authorization. Connection authorization specifies
the access that users have to connect to a system or database. SQL authorization controls
the permissions that users have on database objects or for SQL actions. You
can set the user authorization properties in Derby as
system-level properties or database-level properties.
Set system-level user authorizations when you are developing applications,
or when you want to specify a secure default authorization for all users to
connect to all of the databases in the system.
There are several properties that you can set to control database-level
user authorizations. Some of the properties are general properties that set
the access mode for all users. Other properties are user specific properties
that set the type of access for specific user IDs.
The properties that affect authorization are:
- The derby.database.defaultConnectionMode property controls
the default access mode. Use the derby.database.defaultConnectionMode property
to specify the default connection access that users have when they connect
to the database. If you do not explicitly set the derby.database.defaultConnectionMode property,
the default user authorization for a database is fullAccess,
which is read-write access.
- The derby.database.fullAccessUsers and derby.database.readOnlyAccessUsers properties
are user specific properties. Use these properties to specify the user IDs
that have read-write access and read-only access to a database.
- The derby.database.sqlAuthorization property enables
SQL standard authorization. Use the derby.database.sqlAuthorization property
to specify if object owners can grant and revoke permission for users to perform
SQL actions on database objects. The default setting for the derby.database.sqlAuthorization property
is FALSE. When the derby.database.sqlAuthorization property
is set to TRUE, object owners can use the GRANT and REVOKE
SQL statements to set the user permissions for specific database objects or
for specific SQL actions.
If you do not specify the user authorizations for a specific user ID, the
user ID inherits whatever authorization is set as the default user authorization
for the database.
Tip: If you set the derby.database.defaultConnectionMode property
to noAccess or readOnlyAccess, you should
allow at least one user read-write access. Otherwise, depending on the default
connection authorization you specify, you will configure the database so that
it cannot be accessed or changed.
How user authorization properties work together
The
derby.database.defaultConnectionMode property
and the
derby.database.sqlAuthorization property work together.
The default settings for these properties allow anyone to access and drop
the database objects that you create. You can change the default access mode
by specifying different settings for these properties.
- When the derby.database.sqlAuthorization property is FALSE,
the ability to read from or write to database objects is determined by the
setting for the derby.database.defaultConnectionMode property.
If the derby.database.defaultConnectionMode property is set
to readOnlyAccess, users can access all of the database
objects but they cannot update or drop the objects.
- When the derby.database.sqlAuthorization property is TRUE,
the ability to read from or write to database objects is further restricted
to the owner of the database objects. The owner must grant permission for
others to access the database objects. No one but the owner of an object or
the
database owner
can drop the object.
- The access mode specified for the derby.database.defaultConnectionMode property
overrides the permissions that are granted by the owner of a database object.
For example, if a user is granted INSERT privileges on a table but the user
only has read-only connection authorization, the user cannot insert data into
the table.
Changes to connection authorization settings
Connection
authorization properties are fixed for the duration of a connection. If you
change the connection authorization properties during a connection, those
changes are not in affect until you establish a new connection.
