Capstone Project Partitioned table /dbs

[rocuinneagain]

The sym file contains enumerated symbols for an symbol column in any table.

 

The reason you can select it is that if q fails to find a column of that name it will try to use a global variable , which sym will be.

 

q)`:tab/ set .Q.en[`:.] ([] a:1 2 3;b:`a`b`c) 
`:tab/ 
q)tab:get 
`:tab/ 
q)tab 
a b 
--- 
1 a 
2 b 
3 c 
q)select sym from tab 
sym 
--- 
a 
b 
c 
q)sym //sym is in memory 
`a`b`c 2
q)nonsense:`one`two`three 
q)select nonsense from tab //nonsense is not a column but a global variable 
nonsense 
-------- 
one 
two 
three 
q)delete sym from `. /delete sym from memory 
`. 
q)tab / now any sym columns show indexes as they cannot resolve their text 
a b 
--- 
1 0 
2 1 
3 2

 

Review some documentation on enumeration and on disk data:

• https://code.kx.com/q/basics/enumerations/
• https://code.kx.com/q4m3/14_Introduction_to_Kdb+/#1428-working-with-sym-files