[Maria-discuss] mariasql client question (zappajs, coffeescript, nodejs)

4 Feb 2013

      Hi,

I have switched from mysql to mariadb using it with the node-mysql
client and this has been runing in prod. for some time.

I now want to switch to the mariasql client...

inspect = require('util').inspect
mdbClient = require('mariasql')

...

To do the many queries and simplify the source I wanted to write
a principal function for queries that simply returns an object (or
array) with the query result and then I could just re-use the existing
functionality for the render. So I copied this from the examples

doSql = (sqlstring) ->
   c = new mdbClient()
   c.connect
     host: 'localhost'
     db: 'xyz'     # NOT database
     user: 'abc'
     password: 'defghi'

   c.on("connect", ->
     console.log "Client connected"
   ).on("error", (err) ->
     console.log "Client error: " + err
   ).on "close", (hadError) ->
     console.log "Client closed"

   c.query(sqlstring).on("result", (res) ->
     res.on("row", (row) ->
       console.log "Result row: " + inspect(row)
     ).on("error", (err) ->
       console.log "Result error: " + inspect(err)
     ).on "end", (info) ->
       console.log "Result finished successfully, number of rows: " + 
info.numRows

   ).on "end", ->
     console.log "Done with all results"

   c.end()

....

and then

@get '/': (req,res) ->     # LANDING PAGE)
    result = doSql("select pakz from pkt where pktnr=10001")
    console.log "919, result = ",result
....
@view....

Console log in the doSql functions shows the results correctly but I 
have been
playing around for a while and I can't get the function to return the 
result for
further processing to the @get routine. Seems like I have not understood
the scope issues here and probably a few more things, I am still green 
with this.

My questions

- what is the correct approach to do pass the query object from the function
   to the calling program if this is possible at all?

- how do I access the individual rows the way I do it with node-mysql 
like so
   row[1].myfield ...?

- should I create the instance of the mdbClient in the function or 
rather once at the
   very beginning of the program, my principal worry being stability 
even if the db
   disconnects here and there for some reason?

Thanks, hope this is the right list for this, Karl

-- 
Karl-L. Rumpf
klrumpf@gmail.com
Málaga, Spain