You are free to extend the query in any way you want, as long as it
produces something understood by Cayenne in either 'route' or
'createSQLAction' method. So yeah, you can store parameters in your
custom query, and later bind them via the existing API. Although by
convention query doesn't change its internal state (only the user can
do that), so I would usually clone the query and modify the clone
properties as needed. SelectQuery already has 'queryWithParameters'
that does cloning for you.
Andrus
On Jul 17, 2007, at 6:43 PM, Bryan Lewis wrote:
Awesome. I can use that.
Ummm... could it be made to take a Map of parameters? I could do
it by
adding a statement involving expWithParameters(), right?
Andrus Adamchik wrote:
Here is a small custom query that combines SQLTemplate and
SelectQuery
in one, allowing to fetch the root entity with raw SQL, and still
prefetch related entities as if it were a SelectQuery. Note that
qualifier is ignored for the root entity fetch, but is applied to the
prefetched entities (most often than not qualifier is null though).
Ordering is ignored too, and should be encoded in SQL.
Not sure how common this case is, but I have a real-life situation
where this turned to be invaluable.
public class CustomSQLSelectQuery extends SelectQuery {
protected String rootQuerySQL;
public CustomSQLSelectQuery(Class objectClass, String
rootQuerySQL) {
super(objectClass);
this.rootQuerySQL = rootQuerySQL;
}
public SQLAction createSQLAction(SQLActionVisitor visitor) {
SQLTemplate replacement = new SQLTemplate();
replacement.setRoot(getRoot());
replacement.setDefaultTemplate(rootQuerySQL);
return replacement.createSQLAction(visitor);
}
}
SelectQuery query = new CustomSQLSelectQuery(Artist.class, "<SOME
SQL....>");
query.addPrefetch(Artist.PAINTING_ARRAY);
List artists = dataService.getContext().performQuery(query);
Cheers,
Andrus
