30 lines
867 B
Java
30 lines
867 B
Java
package org.gcube.informationsystem.resourceregistry.queries.operators;
|
|
|
|
/**
|
|
* @author Luca Frosini (ISTI - CNR)
|
|
*
|
|
* Methods: also called "Field Operators"
|
|
*
|
|
* SQL Methods are similar to SQL functions but they apply to values.
|
|
* In Object Oriented paradigm they are called "methods", as functions related to a class.
|
|
* So what's the difference between a function and a method?
|
|
*
|
|
* This is a SQL function:
|
|
*
|
|
* SELECT sum( salary ) FROM employee
|
|
*
|
|
* This is a SQL method:
|
|
*
|
|
* SELECT salary.toJSON() FROM employee
|
|
*
|
|
* As you can see the method is executed against a field/value.
|
|
* Methods can receive parameters, like functions.
|
|
* You can concatenate N operators in sequence.
|
|
*
|
|
* See https://orientdb.com/docs/3.0.x/sql/SQL-Where.html#methods
|
|
* http://orientdb.com/docs/3.0.x/sql/SQL-Methods.html
|
|
*/
|
|
public enum FieldOperator {
|
|
|
|
}
|