Re: [personal kdb+] Elementary loading

Community Support
1

it looks like you’re calling get from the command prompt, not from within q 

within q your file specification is correct, and you’d use 0:

 C:\q>type data.csv

ll,f0,f1

111,222.2,333.3

1234,56.7,8.9

C:\q>q

KDB+ 3.1T 2013.04.03 Copyright (C) 1993-2013 Kx Systems

w64/ 1()core 1023MB Simon simon-w8 192.168.116.137 EXPIRE ..

q)(“JFF”;enlist",")0:`:c:/q/data.csv

ll   f0    f1

111  222.2 333.3

1234 56.7  8.9

q)

see:

http://code.kx.com/wiki/Reference/ZeroColon

2

When I do the steps you show I get:

C:\q>w32\q
KDB+ 3.0 2012.12.22 Copyright (C) 1993-2012 Kx Systems
w32/ 8()core 4095MB Ray antec-pc 192.168.1.107? 2013.03.22

'exp

C:\q>q
‘q’ is not recognized as an internal or external command,
operable program or batch file.

3

'exp - that trial release has expired. Please download the latest from

http://kx.com/software-download.php

thanks

4

Thanks for your assistance that worked; I am obviously new at this. 

I saved my table splayed with no problem but then keyed it on the long. Using set on that causes an error. Is there special syntax for storing keyed tables?

5

Hi Ray,

You can’t save keyed tables as splayed, this is one of the limitations of splayed tables.

http://code.kx.com/wiki/JB:KdbplusForMortals/splayed_tables#1.2.0.2_Limitations_of_Splaying

Perhaps you might consider using a linked column, more information can be found here.

http://code.kx.com/wiki/JB:KdbplusForMortals/splayed_tables#1.2.8_Links_between_Splayed_Tables

http://code.kx.com/wiki/Cookbook/LinkingColumns#Splayed_Tables

Regards,

Paul

6

could also re-apply the key on the fly when mapping the splayed table
e.g.

q)t1:ab xkey select a,b,c from get`:t/

7

My work table will require 53gig. How do I build it directly to disk?

8

you can append to splayed tables using upsert

e.g.

`:splay/ upsert newData

9

Thanks for all your help.
I do not see in qfm or the wiki instructions for self or Cartesian joins or table aliasing. I attempted to use a view for this but did not succeed. In a self join, how can you refer to the identical columns in each joined table?

q)t:( c:1 2 3; x:100 200 300;y:1000 2000 3000)
q)v::select c, x, y from t
q)t
c x?? y

1 100 1000
2 200 2000
3 300 3000
q)v
c x?? y

1 100 1000
2 200 2000
3 300 3000
q)select from t, v
c x?? y

1 100 1000
2 200 2000
3 300 3000
1 100 1000
2 200 2000
3 300 3000
q)select t.c, v.c from t, v
'type

10

there’s an easily overlooked page on code.kx.com which summarizes the available joins in kdb+

http://code.kx.com/wiki/Reference/joins

11

Thanks for the reference. I was following the joins section in qfm and saw most of those, but as I understand the references none seems to supply the equivalent of a SQL Cartesian join. I’d expect 9 rows to result from a self join on my example table t.

12

Cartesian join: www.timestored.com/kdb-guides/qsql-inner-left-joins#nonstandard-sql-inner-join
Use xgroup to group all next lists for each key.

On 4/14/2013 4:57 PM, Ray wrote:

Thanks for the reference. I was following the joins section in qfm and saw most of those, but as I understand the references none seems to supply the equivalent of a SQL Cartesian join. I'd expect 9 rows to result from a self join on my example table t.

On Apr 14, 2013, at 10:14 AM, Charles Skelton <charlie@kx.com> wrote:

there’s an easily overlooked page on code.kx.com which summarizes the available joins in kdb+

http://code.kx.com/wiki/Reference/joins

13

also have a look at cross

e.g.

q)(date:2001.01.01+til 3)cross(time:10:00 11:00)

date       time 

2001.01.01 10:00

2001.01.01 11:00

2001.01.02 10:00

2001.01.02 11:00

2001.01.03 10:00

2001.01.03 11:00

14

perfect, thanks so much!