Re: Lua and Postgres

[Ed <spied@...>]

On 01/14/11 10:48, Marc Balmer wrote:
> The road we went is to write our own PostgreSQL interface, because we
> don't need portability, we just need a solid interface to PostgreSQL:
>
> local res = db:exec("SELECT name FROM persons WHERE id = " .. id)
> for n = 1, res:ntuples() do
>    print(res:getvalue(n, 1)
> end

https://github.com/STPeters/luapgsql

local res = db:exec("SELECT name FROM persons WHERE id = $1", {id})
for r in res:rows()
	print(r.name)
end


> You get the idea...  Currently we are trying to make use of PostgreSQL's
> asynchronous notification feature, linking a notificatin to the
> execution of a Lua function:
>
> db:listen('AN_EVENT', function()
>    print('Event AN_EVENT was signalled')
> end)
>
> Then when e.g. on a psql prompt you enter 'notify AN_EVENT;', above
> function would be called.

my fork of luapgsql:
https://github.com/edo1/luapgsql

db:exec('LISTEN somenotify')
-- wait indefinitely for NOTIFY:
db:notifywait()
-- OR wait for NOTIFY, up to six seconds
db:notifywait(6)

for my needs NOTIFY-wait function is better, but if someone need
NOTIFY-driven callback - it can be added as well.