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 Entire forum ➜ MUSHclient ➜ Lua ➜ SQLite and variables

SQLite and variables

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Posted by Marcopolo   (3 posts)  Bio
Date Sat 27 Mar 2010 04:59 AM (UTC)
Message
Hi, I'm not very familiar with Lua's SQL interface(or SQL for that matter), but I was wondering if there was a way to get a value from a row/column without having to iterate over a table to store it into a variable? Similar to accessing a value directly in a table i.e. myvalue = table['atable']['btable']['something']?

At the moment i'm using nrows. It seems to me, that if I knew what I was looking for, using nrows would be inefficient to put things into variables with.

Thanks.
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Posted by Nick Gammon   Australia  (23,133 posts)  Bio   Forum Administrator
Date Reply #1 on Sat 27 Mar 2010 07:21 AM (UTC)
Message
The whole idea of SQL is to store large amounts of data (eg. a telephone directory) and then get small bits back (eg. the phone number for "Marcopolo") by doing a SELECT statement that limits the amount that is returned.

If you narrow down your search enough (eg. if you look up a player, the player names are unique, and you search by player name) then you should only ever need to get one row.

- Nick Gammon

www.gammon.com.au, www.mushclient.com
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Posted by Marcopolo   (3 posts)  Bio
Date Reply #2 on Sat 27 Mar 2010 08:51 AM (UTC)
Message
I think what I really meant to ask was how I would go about putting the result of a select statement into a variable without dealing with a table?

At the moment I do this:

for a in db:nrows([[SELECT timestamp FROM trade WHERE area = ']]..currentzone..[[']]) do
		last_update=a["timestamp"]
		end


Is this the only way to put a single field of information into a variable? Do all results from a select statement end up being a table?
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Posted by Nick Gammon   Australia  (23,133 posts)  Bio   Forum Administrator
Date Reply #3 on Sun 28 Mar 2010 04:37 AM (UTC)
Message
Well, you *can* - I'm not sure it's worth the effort.

http://www.gammon.com.au/scripts/doc.php?general=lua_sqlite3

You can:




- Nick Gammon

www.gammon.com.au, www.mushclient.com
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