HopObject Query Object

Update: the functionality described in this proposal has been implemented by HopObject.getCollection() - see Creating Collections programmatically.

I've been thinking about a query feature that allows to build HopObject collection on the fly. Under the hood, the query object would be a HopObject with a custom DbMapping. The SQL query would probably be built using a subnodeRelation built from properties of the query object's filter property. These filter conditions could cover a number of common comparison operators:

• columnname - add equal to clause for the column
• columnname_not_equal - add not equal to clause for the column
• columnname_less_than - add less than clause for the column
• columnname_greater_than - add greater than clause for the column
• columnname_less_or_equal - add a less than or equal to clause for the column
• columnname_greater_or_equal - add a greater than or equal for the column
• columnname_like - add like clause for the column
• columnname_not_like - add not like clause for the column
• columnname_is_null - add is null clause for the column
• columnname_not_null - add is not null clause for the column

Query objects could be created by a constructor or factory function passing the arguments as object literals.

  var q = new HopQuery({
     type: Page,
     filter: {
        createtime_greater_than: t1,
        createtime_less_or_equal: t2,
        type_like: "update:%"
     },
     order: "createtime desc"
  });

Links to this page: Re(1): Helma 1.7 wishlist

  Root/type.properties:
  pages= collection(Page)

  this.pages.filter = q;
  var somePages = this.pages.list();

  var q = new HopQuery({
     type: Page,
     filter: {
        creator_in: ['user','admin','guest'],
        type_like: "update:%"
     },
     order: "createtime desc"
  });