Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.programming.threads > #1292

Re: HashDbase and parallel hashlist...

Cross-posted to 2 groups.

Show all headers | View raw

On Wed, 16 Jan 2013 15:35:48 -0800, aminer <aminer@toto.ca> wrote:

>
>Hello,
>
>
>If you ask me the following question:
>
>Amine, why not support SQL joins etc. in HashDbase ?
>
>
>Well i have to write an SQL parser that parser for exemple
>the BNF of the follwing SQL statement for exemple:
>
>"select ed_lname
>from editors, titleeditors
>where editors.ed_id = titleeditors.ed_id
>and titleeditors.title_id = 'PC8888'"
>
>Now the parser that i have to write must validate
>this SQL statement first against the SQL BNF of this SQL statement,
>and after that it has to split the SQL statement
>into mutiple parts, the first part is the "select ed_lname"
>and extract with a BNF the "ed_lname" field that we have
>to return, and after that we have to parse with a BNF the
>"from editors, titleeditors" to extract both the "editors" and
>"titleeditors" tables, and after that we have to parse with
>a BNF  the "where...." part and after that we have to do
>the computing part to return the ed_lname fields.
>
>
>So the very important part to support the joins is to write an SQL parser.
>
>So if i have time to write this project i will support with a parser a 
>small subset of SQL first.


The parser shouldn't be a big deal, the language is not that complex.
A reasonable optimizer, OTOH, *is* a big deal.

Back to comp.programming.threads | Previous | Next | Find similar

Thread

Re: HashDbase and parallel hashlist... Robert Wessel <robertwessel2@yahoo.com> - 2013-01-16 19:03 -0600

csiph-web