Re: NamedQuery / SQLTemplate keyPath validation

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Tue Jun 10 2008 - 03:22:12 EDT

  • Next message: Lachlan Deck: "Re: NamedQuery / SQLTemplate keyPath validation"

    But maybe I misunderstood your goal with that? What about "kePath
    validation" in the subject?

    Andrus

    On Jun 10, 2008, at 10:12 AM, Andrus Adamchik wrote:

    > Hi Lachlan,
    >
    > there is nothing there that would let you do that outside the
    > context of query execution. One reason why we never pursued such
    > functionality is because ... well, such context is needed:
    >
    > * you need a place to stick joins as you walk the expression path
    > * you need a way to match bound variables against "?" in prepared
    > statement (we don't do conversion from Date to String for instance,
    > as there is no sane way to do that for all databases; we let JDBC
    > driver handle bindings)
    > * you need access to specific DbAdapter to generate correct SQL and
    > correctly process bindings.
    >
    > The closest thing to what you describe is a procedure of translation
    > of an EJBQL query (which is logically, but not semantically is a
    > close analog of SelectQuery) to SQLTemplate. It is also done in the
    > context of query execution, but with some effort it can probably be
    > converted to a standalone SQLTemplate without execution.
    >
    > Andrus
    >
    >
    > On Jun 10, 2008, at 9:26 AM, Lachlan Deck wrote:
    >> Hi there,
    >>
    >> (question related to ROP)
    >>
    >> say I've got an Expression (whether complex or otherwise) and I
    >> want to utilise that Expression in a NamedQuery or SQLTemplate...
    >> what's the easiest way to transform the expression to an sql
    >> equivalent string? (i.e., such that, e.g.,, boolean values are
    >> transformed from say true to 1 (if using an int column), dates are
    >> formatted appropriately etc, comparison operators are transformed
    >> (e.g., != to <>) etc.
    >>
    >> I see that there's a QueryAssembler and QualifierTranslator etc,
    >> but what I'm looking for, I guess, is a something like
    >> expression.toSQLString(baseEntity).
    >>
    >> Any suggestions?
    >>
    >> Thanks.
    >>
    >> with regards,
    >> --
    >>
    >> Lachlan Deck
    >>
    >>
    >
    >



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