14.18. Row value constructor syntax

HQL supports the use of ANSI SQL row value constructor syntax, sometimes referred to AS tuple syntax, even though the underlying database may not support that notion. Here, we are generally referring to multi-valued comparisons, typically associated with components. Consider an entity Person which defines a name component:

from Person p where p.name.first='John' and p.name.last='Jingleheimer-Schmidt'

That is valid syntax although it is a little verbose. You can make this more concise by using row value constructor syntax:

from Person p where p.name=('John', 'Jingleheimer-Schmidt')

It can also be useful to specify this in the select clause:

select p.name from Person p

Using row value constructor syntax can also be beneficial when using subqueries that need to compare against multiple values:

from Cat as cat
where not ( cat.name, cat.color ) in (
    select cat.name, cat.color from DomesticCat cat
)

One thing to consider when deciding if you want to use this syntax, is that the query will be dependent upon the ordering of the component sub-properties in the metadata.