Creating a Java Scalar UDF

Create and compile a Java class, install the class file onto the server, and create the function definition.

1. Place this Java code in a file named HelloJavaUDF.java:

   public class HelloJavaUDF
   {
       public static String helloJava( String name )
       {
           // Simply return Hello and the name passed in.
           return "Hello " + name;
       }    
   }

   This creates the Java class HelloJavaUDF with a static method helloJava. The method takes a single string argument and returns a string.

2. Compile HellowJavaUDF.java:
   javac <pathtojavafile>/HelloJavaUDF.java
3. In Interactive SQL, connect to the iqdemo database.
4. In Interactive SQL, install the class file onto the server:

   Option	Description
   Using absolute path	INSTALL JAVA NEW FROM FILE '<absolutepathtofile>/HelloJavaUDF.class' Example: INSTALL JAVA NEW FROM FILE 'd:/mydirectory/HelloJavaUDF.class'
   Using relative path	INSTALL JAVA NEW FROM FILE '<pathrelativetocwd>/HelloJavaUDF.class' Example: INSTALL JAVA NEW FROM FILE 'myreldir/HelloJavaUDF.class'

5. In Interactive SQL, create the function definition.
   Provide the following information:

   • The Java package, class, and method names
   • The Java data types of your function arguments, and their corresponding SQL data types
   • The SQL name assign to the Java UDF

   CREATE FUNCTION my_helloJava(IN name VARCHAR(249) ) 
   RETURNS VARCHAR(255) 
   EXTERNAL NAME 'example.HelloJavaUDF.helloJava(Ljava/lang/String;)Ljava/lang/String;' 
   LANGUAGE JAVA

6. In Interactive SQL, use the Java UDF in a query against the iqdemo database:
   SELECT my_helloJava( GivenName ) FROM Customers WHERE ID < 110