The SET ROLE statement allows you to set the current role for the
current SQL context of a session.
You can set a role only if the current user has been granted the role, or
if the role has been granted to PUBLIC.
For more information on roles, see "Using SQL roles" in the
Derby Developer's Guide.
If you specify a roleName of NONE, the effect is to unset the current
role.
If you specify the role as a string constant or as a dynamic parameter
specification (?), any leading and trailing blanks are trimmed
from the string before attempting to use the remaining (sub)string as a
roleName. The dynamic parameter specification can be used in prepared
statements, so the SET ROLE statement can be prepared once and then executed
with different role values. You cannot specify NONE as a dynamic parameter.
Setting a role identifies a set of privileges that is a union of the
following:
- The privileges granted to that role
- The union of privileges of roles contained in that role (for a definition of
role containment, see "Syntax for roles" in GRANT statement)
In a session, the current privileges define what the session is
allowed to access. The current privileges are the union of the
following:
- The privileges granted to the current user
- The privileges granted to PUBLIC
- The privileges identified by the current role, if set
The SET ROLE statement is not transactional; a rollback does not undo the
effect of setting a role. If a transaction is in progress, an attempt to set a
role results in an error.
Examples
SET ROLE reader;
// These examples show the use of SET ROLE in JDBC statements.
// The case normal form is visible in the SYS.SYSROLES system table.
stmt.execute("SET ROLE admin"); -- case normal form: ADMIN
stmt.execute("SET ROLE \"admin\""); -- case normal form: admin
stmt.execute("SET ROLE none"); -- special case
PreparedStatement ps = conn.prepareStatement("SET ROLE ?");
ps.setString(1, " admin "); -- on execute: case normal form: ADMIN
ps.setString(1, "\"admin\""); -- on execute: case normal form: admin
ps.setString(1, "none"); -- on execute: syntax error
ps.setString(1, "\"none\""); -- on execute: case normal form: none
