org.apache.ignite.cache.query.annotations

Annotation Type QuerySqlFunction

@Documented
 @Retention(value=RUNTIME)
 @Target(value=METHOD)
public @interface QuerySqlFunction

Annotates public static methods in classes to be used in SQL queries as custom functions. Annotated class must be registered in H2 indexing SPI using following method CacheConfiguration.setSqlFunctionClasses(Class[]).

Example usage:

     public class MyFunctions {
         @QuerySqlFunction
         public static int sqr(int x) {
             return x * x;
         }
     }

     // Register.
     indexing.setSqlFunctionClasses(MyFunctions.class);

     // And use in queries.
     cache.queries().createSqlFieldsQuery("select sqr(2) where sqr(1) = 1");
 

For more information about H2 custom functions please refer to H2 documentation.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	alias Specifies alias for the function to be used form SQL queries.
boolean	deterministic Specifies if the function is deterministic (result depends only on input parameters).

Element Detail

alias

public abstract String alias

Specifies alias for the function to be used form SQL queries. If no alias provided method name will be used.

Returns:

Alias for function.

Default:

""

deterministic

public abstract boolean deterministic

Specifies if the function is deterministic (result depends only on input parameters).

Deterministic function is a function which always returns the same result assuming that input parameters are the same.

Returns:

true If function is deterministic, false otherwise.

Default:

false