# User authentication and SQL authorization client example

This example consists of a pair of programs, `AuthExampleClientSQLAuth1.java` and `AuthExampleClientSQLAuth2.java`, which show how to use SQL authorization, in addition to Derby's built-in user authentication and user authorization, with the client driver.

This example uses one program to set properties and a second program to perform database operations. A similar example that uses the embedded driver, in User authentication and SQL authorization embedded example, is a single long program. Either example would work equally well in the other format.

See User authorizations for more information on using SQL authorization, which allows you to use ANSI SQL Standard GRANT and REVOKE statements. Compare this example to the one in User authentication and authorization client example, which does not use SQL authorization.

The first program, `AuthExampleClientSQLAuth1.java`, does the following:

1. Creates a database named `sqlAuthClientDB`, using the client driver. The connection URL creates the database as the user `mary`, who is therefore the database owner. After SQL authorization is enabled, only the database owner will have the right to set and read database properties.
2. Sets database properties that create users with different levels of access (no access, read-only access, and full access), that require authentication, and that turn on SQL authorization. The users `mary` and `sqlsam` have full access.
3. Closes the connection, then shuts down the database so that the authentication and SQL authorization changes can take effect.

The second program, `AuthExampleClientSQLAuth2.java`, does the following:

1. Tries to connect to the database without a username and password, raising an exception.
2. Tries to connect to the database as a user with no access, raising an exception.
3. Connects to the database as a user with read-only access; the connection succeeds, but an attempt to create a table raises an exception.
4. Connects to the database as `mary`, who has full access; this user creates and populates a table. This user also grants select and insert privileges on this table to another user.
5. Connects to the database as `sqlsam`, the user who has been granted select and insert privileges by `mary`. This user has full (that is, read-write) access on the connection level, but has limited powers for this table because SQL authorization is active. The user successfully performs select and insert operations on the table, but an attempt to delete a row from the table raises an exception.
6. Connects to the database again as `mary`, who then deletes the table.
7. Shuts down the database.

Make sure that the `javac` command is in your path, then compile the programs as follows:

`javac AuthExampleClientSQLAuth1.java`

`javac AuthExampleClientSQLAuth2.java`

Before you run the programs, start the Derby Network Server as described in step 2 of "Activity 4: Create and run a JDBC program using the client driver and Network Server" in Getting Started with Derby. When you run the programs, make sure that `%DERBY_HOME%\lib\derbyclient.jar` (or `$DERBY_HOME/lib/derbyclient.jar`) is in your classpath. For example, you might use the following commands on a UNIX system:

`java -cp .:${DERBY_HOME}/lib/derbyclient.jar AuthExampleClientSQLAuth1`

`java -cp .:${DERBY_HOME}/lib/derbyclient.jar AuthExampleClientSQLAuth2`

#### Source code for `AuthExampleClientSQLAuth1.java`

    import java.sql.*;

    public class AuthExampleClientSQLAuth1 {

        public static void main(String[] args) {

            String driver = "org.apache.derby.jdbc.ClientDriver";
            String dbName="sqlAuthClientDB";
            String dbOwner="mary";
            String connectionURL = "jdbc:derby://localhost:1527/" + dbName +
                ";user=" + dbOwner + ";create=true";
            Connection conn = null;

            // Load the driver. This code is not needed if you are using
            // JDK 6, because in that environment the driver is loaded
            // automatically when the application requests a connection.
            try {
                Class.forName(driver);
                System.out.println(driver + " loaded.");
            } catch (java.lang.ClassNotFoundException ce) {
                System.err.print("ClassNotFoundException: ");
                System.err.println(ce.getMessage());
                System.out.println("\n Make sure your CLASSPATH variable " +
                    "contains %DERBY_HOME%\\lib\\derbyclient.jar " +
                    "(${DERBY_HOME}/lib/derbyclient.jar).\n");
            } catch (Exception ee) {
                errorPrintAndExit(ee);
            }

            // Create and boot the database as user mary (who then becomes
            // the database owner), set up users and then shut down the
            // database
            try {
                System.out.println("Trying to connect to " + connectionURL);
                conn = DriverManager.getConnection(connectionURL);
                System.out.println("Connected to database " + connectionURL);

                turnOnBuiltInUsers(conn);

                // Close connection
                conn.close();
                System.out.println("Closed connection");

                /* Shut down the database to make static properties take
                 * effect. Because the default connection mode is now
                 * noAccess, you must specify a user that has access. But
                 * because requireAuthentication and sqlAuthorization do not
                 * take effect until you restart the database, you do not
                 * need to specify a password.
                 *
                 * Database shutdown throws the 08006 exception to confirm
                 * success.
                 */
                try {
                    DriverManager.getConnection(
                        "jdbc:derby://localhost:1527/" + dbName +
                        ";user=mary;shutdown=true");
                } catch (SQLException se)  {
                    if ( !se.getSQLState().equals("08006") ) {
                        throw se;
                    }
                }
                System.out.println("Database shut down normally");
            } catch (Throwable e) {
                errorPrintAndExit(e);
            }
        }

        /**
         * Turn on built-in user authentication and SQL authorization.
         *
         * Default connection mode is fullAccess, but SQL authorization
         * restricts access to the owners of database objects.
         *
         * @param conn a connection to the database
         */
        public static void turnOnBuiltInUsers(Connection conn)
                throws SQLException {

            String setProperty =
                "CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY(";
            String getProperty =
                "VALUES SYSCS_UTIL.SYSCS_GET_DATABASE_PROPERTY(";
            String requireAuth = "'derby.connection.requireAuthentication'";
            String sqlAuthorization = "'derby.database.sqlAuthorization'";
            String defaultConnMode =
                "'derby.database.defaultConnectionMode'";
            String fullAccessUsers = "'derby.database.fullAccessUsers'";
            String readOnlyAccessUsers =
                "'derby.database.readOnlyAccessUsers'";
            String provider = "'derby.authentication.provider'";
            String propertiesOnly = "'derby.database.propertiesOnly'";

            System.out.println(
                "Turning on authentication and SQL authorization.");
            Statement s = conn.createStatement();

            // Set requireAuthentication
            s.executeUpdate(setProperty + requireAuth + ", 'true')");
            // Set sqlAuthorization
            s.executeUpdate(setProperty + sqlAuthorization + ", 'true')");

            // Retrieve and display property values
            ResultSet rs = s.executeQuery(getProperty + requireAuth + ")");
            rs.next();
            System.out.println(
                "Value of requireAuthentication is " + rs.getString(1));

            rs = s.executeQuery(getProperty + sqlAuthorization + ")");
            rs.next();
            System.out.println(
                "Value of sqlAuthorization is " + rs.getString(1));

            // Set authentication scheme to Derby builtin
            s.executeUpdate(setProperty + provider + ", 'BUILTIN')");

            // Create some sample users
            s.executeUpdate(
                setProperty + "'derby.user.sa', 'ajaxj3x9')");
            s.executeUpdate(
                setProperty + "'derby.user.guest', 'java5w6x')");
            s.executeUpdate(
                setProperty + "'derby.user.mary', 'little7xylamb')");
            s.executeUpdate(
                setProperty + "'derby.user.sqlsam', 'light8q9bulb')");

            // Define noAccess as default connection mode
            s.executeUpdate(
                setProperty + defaultConnMode + ", 'noAccess')");

            // Confirm default connection mode
            rs = s.executeQuery(getProperty + defaultConnMode + ")");
            rs.next();
            System.out.println("Value of defaultConnectionMode is " +
                rs.getString(1));

            // Define read-write users
            s.executeUpdate(
                setProperty + fullAccessUsers + ", 'sqlsam,mary')");

            // Define read-only user
            s.executeUpdate(
                setProperty + readOnlyAccessUsers + ", 'guest')");

            // Therefore, user sa has no access

            // Confirm full-access users
            rs = s.executeQuery(getProperty + fullAccessUsers + ")");
            rs.next();
            System.out.println(
                "Value of fullAccessUsers is " + rs.getString(1));

            // Confirm read-only users
            rs = s.executeQuery(getProperty + readOnlyAccessUsers + ")");
            rs.next();
            System.out.println(
                "Value of readOnlyAccessUsers is " + rs.getString(1));

            // We would set the following property to TRUE only when we were
            // ready to deploy. Setting it to FALSE means that we can always
            // override using system properties if we accidentally paint
            // ourselves into a corner.
            s.executeUpdate("CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY(" +
                "'derby.database.propertiesOnly', 'false')");
            s.close();
        }

        /**
         * Report exceptions, with special handling of SQLExceptions,
         * and exit.
         *
         * @param e an exception (Throwable)
         */
        static void errorPrintAndExit(Throwable e) {
            if (e instanceof SQLException)
                SQLExceptionPrint((SQLException)e);
            else {
                System.out.println("A non-SQL error occurred.");
                e.printStackTrace();
            }
            System.exit(1);
        }

        /**
         * Iterate through a stack of SQLExceptions.
         *
         * @param sqle a SQLException
         */
        static void SQLExceptionPrint(SQLException sqle) {
            while (sqle != null) {
                System.out.println("\n---SQLException Caught---\n");
                System.out.println("SQLState:   " + (sqle).getSQLState());
                System.out.println("Severity: " + (sqle).getErrorCode());
                System.out.println("Message:  " + (sqle).getMessage());
                sqle = sqle.getNextException();
            }
        }
    }

#### Source code for `AuthExampleClientSQLAuth2.java`

    import java.sql.*;

    public class AuthExampleClientSQLAuth2 {

        public static void main(String[] args) {

            String driver = "org.apache.derby.jdbc.ClientDriver";
            String dbName="sqlAuthClientDB";
            String dbOwner="mary";
            String connectionURL = "jdbc:derby://localhost:1527/" + dbName;
            Connection conn = null;

            // Restart database and confirm that unauthorized users cannot
            //  access it

            // Load the driver. This code is not needed if you are using
            // JDK 6, because in that environment the driver is loaded
            // automatically when the application requests a connection.
            try {
                Class.forName(driver);
                System.out.println(driver + " loaded.");
            } catch (java.lang.ClassNotFoundException ce) {
                System.err.print("ClassNotFoundException: ");
                System.err.println(ce.getMessage());
                System.out.println("\n Make sure your CLASSPATH variable " +
                    "contains %DERBY_HOME%\\lib\\derbyclient.jar " +
                    "(${DERBY_HOME}/lib/derbyclient.jar). \n");
            } catch (Exception ee) {
                errorPrintAndExit(ee);
            }

            // Try to log in with no username or password
            try {
                // connection attempt should fail
                System.out.println("Trying to connect to " + connectionURL +
                    " without username or password");
                conn = DriverManager.getConnection(connectionURL);
                System.out.println(
                    "ERROR: Unexpectedly connected to database " + dbName);
                cleanUpAndShutDown(conn);
            } catch (SQLException e) {
                if (e.getSQLState().equals("08004")) {
                    System.out.println("Correct behavior: SQLException: " +
                        e.getMessage());
                } else {
                    errorPrintAndExit(e);
                }
            }

            // Try to log in as a valid user with noAccess
            try {
                // connection attempt should fail
                String newURL = connectionURL + ";user=sa;password=ajaxj3x9";
                System.out.println("Trying to connect to " + newURL);
                conn = DriverManager.getConnection(newURL);
                System.out.println(
                    "ERROR: Unexpectedly allowed to connect to database " +
                         dbName);
                cleanUpAndShutDown(conn);
            } catch (SQLException e) {
                if (e.getSQLState().equals("08004")) {
                    System.out.println("Correct behavior: SQLException: " +
                        e.getMessage());
                } else {
                    errorPrintAndExit(e);
                }
            }

            // Log in as a user with read-only access
            try {
                // connection should succeed, but create table should fail
                String newURL = connectionURL +
                    ";user=guest;password=java5w6x";
                System.out.println("Trying to connect to " + newURL);
                conn = DriverManager.getConnection(newURL);
                System.out.println("Connected to database " + dbName +
                    " with read-only access");

                Statement s = conn.createStatement();
                s.executeUpdate(
                    "CREATE TABLE accessibletbl(textcol VARCHAR(6))");
                System.out.println(
                    "ERROR: Unexpectedly allowed to modify database " +
                         dbName);
                cleanUpAndShutDown(conn);
            } catch (SQLException e) {
                if (e.getSQLState().equals("25503")) {
                    System.out.println("Correct behavior: SQLException: " +
                        e.getMessage());
                    try {
                        conn.close();
                    } catch (SQLException ee) {
                        errorPrintAndExit(ee);
                    }
                } else {
                    errorPrintAndExit(e);
                }
            }

            // Log in as a user with full access
            // Create, update, and query table
            // Grant select and insert privileges to another user
            try {
                // this should succeed
                String newURL = connectionURL +
                    ";user=mary;password=little7xylamb";
                System.out.println("Trying to connect to " + newURL);
                conn = DriverManager.getConnection(newURL);
                System.out.println("Connected to database " + dbName);

                Statement s = conn.createStatement();

                s.executeUpdate(
                    "CREATE TABLE accessibletbl(textcol VARCHAR(6))");
                System.out.println("Created table accessibletbl");
                s.executeUpdate("INSERT INTO accessibletbl VALUES('hello')");

                ResultSet rs = s.executeQuery("SELECT * FROM accessibletbl");
                rs.next();
                System.out.println("Value of accessibletbl/textcol is " +
                    rs.getString(1));

                // grant insert privileges on table to user sqlsam
                s.executeUpdate(
                    "GRANT SELECT, INSERT ON accessibletbl TO sqlsam");
                System.out.println(
                    "Granted select/insert privileges to sqlsam");

                s.close();
                conn.close();
            } catch (SQLException e) {
                errorPrintAndExit(e);
            }

            // Log in as user with select and insert privileges on the table,
            //  but not delete privileges
            try {
                String newURL =
                    connectionURL + ";user=sqlsam;password=light8q9bulb";
                System.out.println("Trying to connect to " + newURL);
                conn = DriverManager.getConnection(newURL);
                System.out.println("Connected to database " + dbName);

                // look at table
                Statement s = conn.createStatement();
                ResultSet rs =
                    s.executeQuery("SELECT * FROM mary.accessibletbl");
                rs.next();
                System.out.println("Value of accessibletbl/textcol is " +
                    rs.getString(1));

                s.executeUpdate(
                    "INSERT INTO mary.accessibletbl VALUES('sam')");
                System.out.println("Inserted string into table");

                rs = s.executeQuery("SELECT * FROM mary.accessibletbl");
                while (rs.next()) {
                   System.out.println("Value of accessibletbl/textcol is " +
                       rs.getString(1));
                }
                s.close();
            } catch (SQLException e) {
                errorPrintAndExit(e);
            }

            try {
                Statement s = conn.createStatement();

                // this should fail
                s.executeUpdate("DELETE FROM mary.accessibletbl " +
                    "WHERE textcol = 'hello'");
                System.out.println("ERROR: Unexpectedly allowed to DELETE " +
                    "table mary.accessibletbl");
                cleanUpAndShutDown(conn);
            } catch (SQLException e) {
                if (e.getSQLState().equals("42500")) {
                    System.out.println("Correct behavior: SQLException: " +
                        e.getMessage());
                    try {
                        conn.close();
                    } catch (SQLException ee) {
                        errorPrintAndExit(ee);
                    }
                } else {
                    errorPrintAndExit(e);
                }
            }

            /* Log in again as mary, delete table
             */
            try {
                String newURL = connectionURL +
                    ";user=mary;password=little7xylamb";
                System.out.println("Trying to connect to " + newURL);
                conn = DriverManager.getConnection(newURL);
                System.out.println("Connected to database " + dbName);

                Statement s = conn.createStatement();
                s.executeUpdate("DROP TABLE accessibletbl");
                System.out.println("Removed table accessibletbl");
                s.close();
            } catch (SQLException e) {
                errorPrintAndExit(e);
            }

            try {
                cleanUpAndShutDown(conn);
            } catch (SQLException e) {
                errorPrintAndExit(e);
            }
        }

        /** Close connection and shut down database.
         *
         * @param conn a connection to the database
         */
        public static void cleanUpAndShutDown (Connection conn)
                throws SQLException {

            String dbName="sqlAuthClientDB";
            String dbOwner="mary";
            String connectionURL = "jdbc:derby://localhost:1527/" + dbName;

            try {
                conn.close();
                System.out.println("Closed connection");

                // As mary, the database owner, shut down the database.
                try {
                    String newURL = connectionURL + ";user=" + dbOwner +
                        ";password=little7xylamb;shutdown=true";
                    DriverManager.getConnection(newURL);
                } catch (SQLException se) {
                    if ( !se.getSQLState().equals("08006") ) {
                        throw se;
                    }
                }
                System.out.println("Database shut down normally");
            } catch (SQLException e) {
                errorPrintAndExit(e);
            }
        }

        /**
         * Report exceptions, with special handling of SQLExceptions,
         * and exit.
         *
         * @param e an exception (Throwable)
         */
        static void errorPrintAndExit(Throwable e) {
            if (e instanceof SQLException)
                SQLExceptionPrint((SQLException)e);
            else {
                System.out.println("A non-SQL error occurred.");
                e.printStackTrace();
            }
            System.exit(1);
        }

        /**
         * Iterate through a stack of SQLExceptions.
         *
         * @param sqle a SQLException
         */
        static void SQLExceptionPrint(SQLException sqle) {
            while (sqle != null) {
                System.out.println("\n---SQLException Caught---\n");
                System.out.println("SQLState:   " + (sqle).getSQLState());
                System.out.println("Severity: " + (sqle).getErrorCode());
                System.out.println("Message:  " + (sqle).getMessage());
                sqle = sqle.getNextException();
            }
        }
    }

Parent topic: User authentication examples using SQL authorization