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From Alexey Kuznetsov <akuznet...@apache.org>
Subject Re: Do not use H2 parser for DDL
Date Fri, 27 Jan 2017 12:15:01 GMT
We should care about statements like this:
/* bla-bla */ CREATE TABLE

So naive "startsWith(...)" will not work in some scenarios.

:)

On Fri, Jan 27, 2017 at 7:06 PM, Vladimir Ozerov <vozerov@gridgain.com>
wrote:

> Folks,
>
> H2 has nice and powerful SQL parser, and we pass all incoming SQL commands
> through it. However it doesn't support custom SQL syntax, which we are
> likely to need in DDL at some point in future.
>
> As DDL statements are relatively easy to parse comparing to SELECTs and
> they do not involve optimizer, we can easily create object model of DDL
> command without invoking H2 at all.
>
> I propose to introduce small change into our parsing logic as follows:
>
> if (req.startsWith("CREATE" or "ALTER" or "DELETE")
>     parseDdlManually(req);
> else
>     parseWithH2(req);
>
> It should be enough to support any custom syntax for our DDL with any
> limitations and without any dependencies on H2 folks.
>
> For instance, see H2 "CREATE TABLE" [1] and "CREATE INDEX" [2] structure.
> It is already very simple. But provided that Ignite doesn't support most of
> H2 DDL features, Ignite DDL structure will be even simpler.
>
> it should take no more than 1-2 days to implement fully-fledged parsing for
> these two commands.
>
> Thoughts?
>
> Vladimir.
>
> [1] http://www.h2database.com/html/grammar.html#create_table
> [2] http://www.h2database.com/html/grammar.html#create_index
>



-- 
Alexey Kuznetsov

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