Updating a linked column

Community Support
1

Hi all,

I am trying to update a linked column but am receiving an error.

I have a function similar to

updateCol:{[d]:c:/hdb/2015.05.01/trade/ set (update mas:mas!mas.sym?sym from select from trade where date=d)};

I added the original linked col by using 

addcol[:/hdb;trade;mas;{mas!mas.sym?get()sv x, sym}];

but its out of date now and want to update it.

When I run the updateCol function I get an access is denied error.  I think the problem lies in the “select from trade where date=d” part because when I pull this out of the function the table is too large.  Is there another better way to do this?

2

it may be because select from trade where date=d keeps a reference to the file on disk, which is then locked when you try to set<o:p></o:p>

<o:p> </o:p>

You can read the column into memory and then writ it down:<o:p></o:p>

<o:p> </o:p>

updateCol:{[d] f set mas!mas.sym?get f: :c:/hdb/2015.05.01/trade/sym)};<o:p></o:p>

<o:p> </o:p>

which would also be way more efficient because you are only reading/writing the one column<o:p></o:p>

<o:p> </o:p>

From: personal-kdbplus@googlegroups.com [mailto:personal-kdbplus@googlegroups.com] On Behalf Of Roni Hoffman
Sent: Friday, June 5, 2015 5:02 AM
To: personal-kdbplus@googlegroups.com
Subject: [personal kdb+] Updating a linked column<o:p></o:p>

<o:p> </o:p>

Hi all,<o:p></o:p>

<o:p> </o:p>

I am trying to update a linked column but am receiving an error.<o:p></o:p>

<o:p> </o:p>

I have a function similar to<o:p></o:p>

<o:p> </o:p>

updateCol:{[d]:c:/hdb/2015.05.01/trade/ set (update mas:mas!mas.sym?sym from select from trade where date=d)};<o:p></o:p>

I added the original linked col by using <o:p></o:p>

<o:p> </o:p>

 addcol[:/hdb;trade;mas;{mas!mas.sym?get()sv x, sym}];<o:p></o:p>

but its out of date now and want to update it.<o:p></o:p>

<o:p> </o:p>

When I run the updateCol function I get an access is denied error.  I think the problem lies in the “select from trade where date=d” part because when I pull this out of the function the table is too large.  Is there another better way to do this?<o:p></o:p>

–
Submitted via Google Groups

3

I see, thanks very much David