Wrapping is the process of hiding PLSQL source code. Wrapping helps to protect your source code from business competitors and others who might misuse it. You can wrap PLSQL source code with either the wrap utility or DBMS_DDL subprograms. The wrap utility wraps a single source file, such as a SQL*Plus script. The DBMS_DDL subprograms wrap a single dynamically generated PLSQL unit, such as a single CREATE PROCEDURE statement.
Wrapped source files can be moved,
backed up, and processed by SQL*Plus and the Import and Export utilities, but they are not visible
through the static data dictionary views *_SOURCE.
Guidelines for Wrapping
- Wrap only the body of a package or object type, not the specification. This allows other developers to see the information they must use the package or type, but prevents them from seeing its implementation.
- Wrap code only after you have finished editing it. You cannot edit PL/SQL source code inside wrapped files. Either wrap your code after it is ready to ship to users or include the wrapping operation as part of your build environment. To change wrapped PL/SQL code, edit the original source file and then wrap it again.
- Before distributing a wrapped file, view it in a text editor to be sure that all important parts are wrapped.
Limitations of Wrapping
- Wrapping is not a secure method for hiding passwords or table names. Wrapping a PL/SQL unit prevents most users from examining the source code, but might not stop all of them.
- Wrapping does not hide the source code for triggers. To hide the workings of a trigger, write a one-line trigger that invokes a wrapped subprogram.
- Wrapping does not detect syntax or semantic errors. Wrapping detects only tokenization errors (for example, runaway strings), not syntax or semantic errors (for example, nonexistent tables or views). Syntax or semantic errors are detected during PL/SQL compilation or when executing the output file in SQL*Plus.
- Wrapped PL/SQL units are not downward-compatible. Wrapped PL/SQL units are upward-compatible between Oracle Database releases, but are not downward-compatible.
Wrapping PL/SQL Code with wrap Utility
The wrap
utility processes
an input SQL file and wraps only the PL/SQL units in the file, such as a
package specification, package body, function, procedure, type specification,
or type body. It does not wrap PL/SQL content in anonymous blocks or triggers
or non-PL/SQL code.
To run the wrap utility, enter the wrap command at your operating system prompt using the
following syntax (with no spaces around the equal signs):
wrap iname=input_file [ oname=output_file ]
input_file is the name of a file containing SQL statements, that
you typically run using SQL*Plus. If you omit the file extension, an extension
of .sql is assumed. For example, the following
commands are equivalent:
wrap iname=/mydir/myfile
wrap iname=/mydir/myfile.sql
You can also specify a different file extension:
wrap iname=/mydir/myfile.src
output_file is the name of the wrapped file that is created. The defaults to that of
the input file and its extension default is .plb. For example, the
following commands are equivalent:
wrap iname=/mydir/myfile
wrap iname=/mydir/myfile.sql
oname=/mydir/myfile.plb
You can use the option oname to specify a
different file name and extension:
wrap iname=/mydir/myfile
oname=/yourdir/yourfile.out
Input and Output Files for the PL/SQL wrap Utility
The input file can contain any
combination of SQL statements. Most statements are passed through unchanged. CREATE statements that define subprograms, packages, or object
types are wrapped; their bodies are replaced by a scrambled form that the PLSQL
compiler understands.
The following CREATE statements are
wrapped:
CREATE [OR REPLACE] FUNCTION function_name
CREATE [OR REPLACE] PROCEDURE
procedure_name
CREATE [OR REPLACE] PACKAGE package_name
CREATE [OR REPLACE] PACKAGE BODY
package_name
CREATE [OR REPLACE] TYPE type_name AS
OBJECT
CREATE [OR REPLACE] TYPE type_name UNDER
type_name
CREATE [OR REPLACE] TYPE BODY type_name
The CREATE [OR REPLACE] TRIGGER statement, and [DECLARE] BEGIN-END anonymous blocks, are not wrapped. All other SQL
statements are passed unchanged to the output file.
All comment lines in the unit being wrapped are
deleted, except for those in a CREATE OR REPLACE header and C-style comments (delimited by /* */). The output file is a text file, which you can run
as a script in SQL*Plus to set up your PL/SQL subprograms and packages. Run a
wrapped file as follows:
SQL> @wrapped_file_name.plb;
Using DBMS_DDL.CREATE_WRAPPED Procedure
In the below example CREATE_WRAPPED is used to dynamically
create and wrap a package specification and a package body in a database.
Example: Using
DBMS_DDL.CREATE_WRAPPED Procedure to Wrap a Package
DECLARE
package_text VARCHAR2(32767); -- text for creating package spec & body
FUNCTION generate_spec(pkgname VARCHAR2) RETURN VARCHAR2 AS
BEGIN
RETURN 'CREATE PACKAGE ' || pkgname || ' AS
PROCEDURE raise_salary (emp_id NUMBER, amount NUMBER);
PROCEDURE fire_employee (emp_id NUMBER);
END ' ||
pkgname || ';';
END generate_spec;
FUNCTION generate_body(pkgname VARCHAR2) RETURN VARCHAR2 AS
BEGIN
RETURN 'CREATE PACKAGE BODY ' || pkgname || ' AS
PROCEDURE raise_salary (emp_id NUMBER, amount NUMBER) IS
BEGIN
UPDATE employees
SET salary = salary + amount WHERE employee_id = emp_id;
END raise_salary;
PROCEDURE fire_employee (emp_id NUMBER) IS
BEGIN
DELETE FROM employees WHERE employee_id = emp_id;
END fire_employee;
END ' ||
pkgname || ';';
END generate_body;
BEGIN
-- Generate package spec
package_text := generate_spec('emp_actions')
-- Create wrapped package spec
DBMS_DDL.CREATE_WRAPPED(package_text);
-- Generate package body
package_text := generate_body('emp_actions');
-- Create wrapped package body
DBMS_DDL.CREATE_WRAPPED(package_text);
END;
-- Invoke procedure from wrapped
package
CALL emp_actions.raise_salary(120, 100);
When you check the static data dictionary views *_SOURCE, the source is wrapped, or hidden, so that others
cannot view the code details. For example:
SELECT text FROM
USER_SOURCE WHERE name = 'EMP_ACTIONS';
The resulting output is similar to the following:
TEXT
--------------------------------------------------------------------
PACKAGE emp_actions WRAPPED
a000000
1f
abcd
...
