Introduction to MLE Module Calls

It is possible to create JavaScript modules as schema objects that are stored persistently in the database.

Once a JavaScript module has been defined, it can be used in SQL and PL/SQL as shown below:

CREATE OR REPLACE MLE MODULE helloWorld_module
LANGUAGE JAVASCRIPT AS
function helloWorld() {
    console.log('Hello World, this is a JS module');
}
export { helloWorld }
/

Before the exported JavaScript function can be invoked, a call specification must be defined. The code snippet below shows how to create a call specification for the JavaScript helloWorld() function in PL/SQL:

CREATE OR REPLACE PROCEDURE helloWorld_proc
AS MLE MODULE helloWorld_module
SIGNATURE 'helloWorld()';
/

The call specification, referred to as an MLE module call, publishes the JavaScript function helloWorld(). It can then be used just like any other PL/SQL procedure. The following snippet shows how to invoke the function along with the results:

SET SERVEROUTPUT ON

BEGIN
    helloWorld_proc;
END;
/

Result:

Hello World, this is a JS module

In addition to custom-built JavaScript modules as shown in the provided code, it is possible to load third-party JavaScript modules into the database. Note that Oracle recommends performing a security screening of third-party code according to industry best practice.