Package org.apache.ignite.cache.query.annotations

Annotation Type QuerySqlTableFunction

@Documented
@Retention(RUNTIME)
@Target(METHOD)
public @interface QuerySqlTableFunction

Annotates public methods in classes to be used in SQL queries as custom table functions. Annotated class must be registered using CacheConfiguration.setSqlFunctionClasses(Class[]).

Usage example:

     public class MyTableFunctions {
         @QuerySqlTableFunction(columnTypes = {Float.class, String.class}, columnNames = {"F_VAL", "S_VAL"})
         public static Iterable<Object[]> my_table(int i, Float f, String str) {
             return Arrays.asList(
                 new Object[]{f, "code_" + (i * 10) + ": " + str},
                 new Object[]{null, "code_" + (i * 20) + ": " + str},
                 new Object[]{f,  "code_" + (i * 30) + ": " + str}
             );
         }
     }

     // Register in CacheConfiguration.
     cacheCfg.setSqlFunctionClasses(MyTableFunctions.class);

     // And use in queries.
     cache.query(new SqlFieldsQuery("select S_VAL from MY_TABLE(1, 5.0f, "ext") where F_VAL is not null"));
 

Table function must return an Iterable as a row set. Each row can be represented by an Object[] or by an Collection. Row length must match the defined number of column types. Row value types must match the defined column types or be able assigned to them.

Note, the table functions are available currently only with Calcite.

See Also:

QuerySqlFunction, SessionContextProviderResource

Required Element Summary

Required Elements

Modifier and Type	Required Element	Description
String[]	columnNames	Defines column names of the returned SQL table representation.
Class<?>[]	columnTypes	Defines column types of the returned SQL table representation.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
String	alias	Specifies alias for the table function name to be used form SQL queries.

Element Detail

columnTypes

Class<?>[] columnTypes

Defines column types of the returned SQL table representation. Number of the types must match number of columnNames().

Returns:

Table column types.

columnNames

String[] columnNames

Defines column names of the returned SQL table representation. Number of the names must match number of columnTypes().

Returns:

Table column names.

alias

String alias

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

Returns:

Alias for table function name.

Default:

""