calcite-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Muhammad Gelbana <m.gelb...@gmail.com>
Subject Re: Pluggable JDBC types
Date Mon, 03 Jun 2019 03:28:07 GMT
That was my first attempt and it worked, but Julian pointed out that I can
support a type without modifying the parser (which I prefer) but I couldn't
get it to return the column type name as I wish.

Thanks,
Gelbana


On Mon, Jun 3, 2019 at 3:13 AM Yuzhao Chen <yuzhao.cyz@gmail.com> wrote:

> You don’t need to, just define a new type name in parser[1] and translate
> it to VARCHAR is okey.
>
> [1]
> https://github.com/apache/calcite/blob/b0e83c469ff57257c1ea621ff943ca76f626a9b7/server/src/main/codegen/config.fmpp#L375
>
> Best,
> Danny Chan
> 在 2019年6月3日 +0800 AM6:09,Muhammad Gelbana <m.gelbana@gmail.com>,写道:
> > That I understand now. But how can I support casting to TEXT and having
> the
> > returned column type name as TEXT (ie. Not VARCHAR) ?
> >
> > Thanks,
> > Gelbana
> >
> >
> > On Sun, Jun 2, 2019 at 7:41 PM Julian Hyde <jhyde@apache.org> wrote:
> >
> > > The parser should only parse, not validate. This is a very important
> > > organizing principle for the parser.
> > >
> > > If I write “x :: text” or “x :: foo” it is up to the type system
> > > (implemented in the validator and elsewhere) to figure out whether
> “text”
> > > or “foo” are valid types.
> > >
> > > Logically, “x :: foo” is the same as “CAST(x AS foo)”. The parser
> should
> > > produce the same SqlCall in both cases. Then the parser’s job is done.
> > >
> > > Julian
> > >
> > >
> > > > On Jun 2, 2019, at 6:42 AM, Muhammad Gelbana <m.gelbana@gmail.com>
> > > wrote:
> > > >
> > > > I'm trying to support the PostgreSQL TEXT type[1]. It's basically a
> > > VARCHAR.
> > > >
> > > > As Julian mentioned in his comment on Jira, I don't need to define a
> > > > keyword to achieve what I need so I tried exploring that and here is
> > > what I
> > > > observed so far:
> > > >
> > > > 1. If I define a new keyword in the parser, I face no trouble
> whatsoever
> > > > except for the numerous wiring I need to do for RexToLixTranslator,
> > > > JavaTypeFactoryImpl, SqlTypeAssignmentRules and SqlTypeName. I won't
> be
> > > > suprised if I'm missing anything but doing what I did at first
> managed to
> > > > get my queries through.
> > > >
> > > > 2. If I define the type by plugging it in through the root schema, I
> face
> > > > two problems: a) The field cannot be declared as nullable because the
> > > query
> > > > I'm using for testing gets data from (VALUES()) which doesn't produce
> > > null
> > > > values, so an exception is thrown. b) The returned column type name
> is
> > > > VARCHAR (although I delcared the new plugged type name to be TEXT),
> the
> > > > returned type number is valid though (Types.VARCHAR = 12)
> > > >
> > > > I think I'm doing something wrong that causes (2.a) but (2.b) seems a
> > > like
> > > > a bug to me. What do you think ?
> > > >
> > > > [1] https://issues.apache.org/jira/browse/CALCITE-3108
> > > >
> > > > Thanks,
> > > > Gelbana
> > >
> > >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message