27.3 JavaScript Stored Programs

27.3.1 JavaScript Stored Program Creation and Management

27.3.2 Obtaining Information About JavaScript Stored Programs

27.3.3 JavaScript Stored Program Language Support

27.3.4 JavaScript Stored Program Data Types and Argument Handling

27.3.5 JavaScript Stored Programs—Obtaining Session Information

27.3.6 JavaScript SQL API

27.3.7 Using the JavaScript SQL API

27.3.8 JavaScript Stored Program Limitations and Restrictions

27.3.9 JavaScript Stored Program Examples

MySQL 9.0 supports stored routines written in JavaScript, as in the simple example shown here:

mysql> CREATE FUNCTION add_nos(arg1 INT, arg2 INT) 
    ->   RETURNS INT LANGUAGE JAVASCRIPT AS 
    ->   $$
    $>     return arg1 + arg2
    $>   $$
    ->   ;
Query OK, 0 rows affected (0.01 sec)

mysql> SELECT add_nos(12,52);
+----------------+
| add_nos(12,52) |
+----------------+
|             64 |
+----------------+
1 row in set (0.00 sec)

Note

Support for JavaScript stored routines requires installation of the Multilingual Engine (MLE) component. For information about installing and configuring the MLE component, see Section 7.5.6, “Multilingual Engine Component (MLE)”.

JavaScript stored programs can be used together with other user-created and MySQL-native stored programs (subject to limitations described elsewhere in this section), as well as with MySQL system and user variables. We can see some of this here, using the add_nos() function created in the previous example:

mysql> SET @x = 2;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @x;
+------+
| @x   |
+------+
|    2 |
+------+
1 row in set (0.00 sec)

mysql> SELECT @@server_id;
+-------------+
| @@server_id |
+-------------+
|           1 |
+-------------+
1 row in set (0.00 sec)

mysql> SELECT add_nos(POW(2,@x), 1);
+-----------------------+
| add_nos(POW(2,@x), 1) |
+-----------------------+
|                     5 |
+-----------------------+
1 row in set (0.01 sec)

mysql> SELECT POW(add_nos(@x, @@server_id), add_nos(@x, 1));
+-----------------------------------------------+
| POW(add_nos(@x, @@server_id), add_nos(@x, 1)) |
+-----------------------------------------------+
|                                            27 |
+-----------------------------------------------+
1 row in set (0.01 sec)

JavaScript stored procedures can be invoked using CALL, as with SQL stored procedures.

JavaScript stored programs can also take column values as arguments. JavaScript stored functions can be invoked anywhere in an SQL expression that it is legal to use any other function, such as in WHERE, HAVING, ORDER BY, and JOIN clauses. They can also be invoked within the body of a trigger or event definition, although the definitions themselves must be written in SQL. Examples of some of these features can be found later in this section (see Section 27.3.9, “JavaScript Stored Program Examples”).