static boolean attributeCreated(ImmutableSDField field, String attributeName) {
        if ( ! field.doesAttributing()) {
            return false;
        }
        for (Attribute attribute : field.getAttributes().values()) {
            if (attribute.getName().equals(attributeName)) {
                return true;
            }
        }
        return false;
    }
Checks if the attribute has been created bye an indexing statement in this field.

@param field         a schema field
@param attributeName name of the attribute
@return true if the attribute has been created by this field, else false
config-model/src/main/java/com/yahoo/schema/processing/AttributeProperties.java