Queries¶

WebDSL supports a subset of HQL. You can use these queries directly in your webdsl program, by for example assigning them to variables. An example:

  // select all updates
  var allUpdates : [Update] := from Update;

Escaping¶

Often it is useful to use values from your WebDSL program inside a query. To do this you can escape WebDSL expressions by prefixing them with a tilde (~).

To escape to WebDSL inside a query, prefix the expression with ~. For example:

  // Select all users whose username is "zef"
  var username : String := "zef";
  var users : [User] := from User as u where u.username = ~username;

Notes¶

Limit accepts either one or two arguments. With one argument it just limits, but in the two argument form, the first argument describes the offset. Even though offset is valid SQL, it's not a valid keyword to use in WebDSL queries, even though it is a valid keyword in other places in WebDSL so will be highlighted in your editor.

Example: a paginated view¶

// A paginated for, showing 10 items per page and prefetch the "user" column (in a template)
var page : Int := 0;
for(update : Update in from Update as u left join fetch u.user order by u.date desc limit 10*page, 10) {
   output(update.text)
}