use example as provided by PL/SQL Cop

Author: PhilippSalvisberg

docs/4-language-usage/8-patterns/4-ensure-single-execution-at-a-time-of-a-program-unit/g-8410.md

@@ -12,43 +12,39 @@ The alternative using a table where a “Lock-Row” is stored has the disadvant
 ## Example (bad)
 
 ```
--- create locking table
-CREATE TABLE application_locks (
-   lock_name VARCHAR2(128 CHAR) NOT NULL PRIMARY KEY
-  ,lock_time TIMESTAMP          NOT NULL
-) ORGANIZATION INDEX;
--- definition
+-- Bad
+/* Example */
 CREATE OR REPLACE PACKAGE BODY lock_up IS
+   -- manage locks in a dedicated table created as follows:
+   --   CREATE TABLE app_locks (
+   --      lock_name VARCHAR2(128 CHAR) NOT NULL primary key
+   --   );
+
    PROCEDURE request_lock (in_lock_name IN VARCHAR2) IS
-      PRAGMA AUTONOMOUS_TRANSACTION;
    BEGIN
-      INSERT INTO application_locks (lock_name, lock_time) VALUES (in_lock_name, systimestamp);
-      COMMIT;
-   EXCEPTION
-      WHEN DUP_VAL_ON_INDEX THEN
-         RAISE err.e_lock_request_failed;
+      -- raises dup_val_on_index
+      INSERT INTO app_locks (lock_name) VALUES (in_lock_name);
    END request_lock;
-   
-   PROCEDURE release_lock (in_lock_name IN VARCHAR2) IS
-      PRAGMA AUTONOMOUS_TRANSACTION;
+
+   PROCEDURE release_lock(in_lock_name IN VARCHAR2) IS
    BEGIN
-      DELETE FROM application_locks
-       WHERE lock_name = in_lock_name;
-      COMMIT;
+      DELETE FROM app_locks WHERE lock_name = in_lock_name;
    END release_lock;
 END lock_up;
 /
--- call
+
+/* Call bad example */
 DECLARE
+   l_handle VARCHAR2(128 CHAR);
    co_lock_name CONSTANT VARCHAR2(30 CHAR) := 'APPLICATION_LOCK';
 BEGIN
-   lock_up.request_lock(in_lock_name => co_lock_name);
+   l_handle := lock_up.request_lock(in_lock_name => co_lock_name);
    -- processing
-   lock_up.release_lock(in_lock_name => co_lock_name);
+   lock_up.release_lock(in_lock_handle => l_handle);
 EXCEPTION
    WHEN OTHERS THEN
       -- log error
-      lock_up.release_lock(in_lock_name => co_lock_name);
+      lock_up.release_lock(in_lock_handle => l_handle);
       RAISE;
 END;
 /
@@ -57,36 +53,41 @@ END;
 ## Example (good)
 
 ```
--- definition
+/* Example */
 CREATE OR REPLACE PACKAGE BODY lock_up IS
-   FUNCTION request_lock (in_lock_name         IN VARCHAR2
-                         ,in_release_on_commit IN BOOLEAN := FALSE) RETURN VARCHAR2 IS
+   FUNCTION request_lock(
+      in_lock_name         IN VARCHAR2,
+      in_release_on_commit IN BOOLEAN := FALSE) 
+   RETURN VARCHAR2 IS
       l_lock_handle VARCHAR2(128 CHAR);
    BEGIN
-      SYS.DBMS_LOCK.ALLOCATE_UNIQUE (lockname        => in_lock_name
-                                    ,lockhandle      => l_lock_handle
-                                    ,expiration_secs => constants_up.co_one_week); 
-       
-      IF sys.DBMS_LOCK.REQUEST(lockhandle        => l_lock_handle
-                              ,lockmode          => sys.DBMS_LOCK.X_MODE
-                              ,TIMEOUT           => sys.DBMS_LOCK.MAXWAIT
-                              ,release_on_commit => COALESCE(in_release_on_commit
-                                                            ,FALSE)) > 0 THEN
+      sys.dbms_lock.allocate_unique(
+         lockname        => in_lock_name,
+         lockhandle      => l_lock_handle,
+         expiration_secs => constants_up.co_one_week
+      );
+      IF sys.dbms_lock.request(
+            lockhandle        => l_lock_handle,
+            lockmode          => sys.dbms_lock.x_mode,
+            timeout           => sys.dbms_lock.maxwait,
+            release_on_commit => COALESCE(in_release_on_commit, FALSE)
+         ) > 0 
+      THEN
          RAISE err.e_lock_request_failed;
       END IF;
-      
       RETURN l_lock_handle;
    END request_lock;
-   
-   PROCEDURE release_lock (in_lock_handle IN VARCHAR2) IS
+
+   PROCEDURE release_lock(in_lock_handle IN VARCHAR2) IS
    BEGIN
-     IF sys.DBMS_LOCK.RELEASE(lockhandle => in_lock_handle) > 0 THEN
+      IF sys.dbms_lock.release(lockhandle => in_lock_handle) > 0 THEN
          RAISE err.e_lock_request_failed;
-     END IF;
+      END IF;
    END release_lock;
 END lock_up;
 /
--- call
+
+/* Call good example */
 DECLARE
    l_handle VARCHAR2(128 CHAR);
    co_lock_name CONSTANT VARCHAR2(30 CHAR) := 'APPLICATION_LOCK';