Odtnhj

I would like to change a certain value in one column in hdb to another value. I tried using dbmaint package. However I got some type error.

This is the code I have

fncol[DB;TBL;`col;x:ssr[string x;"100";"i"$"0"]];

I am trying to change the value 100 to 0 in this column to all dates in hdb.

the reason you are getting a type error is because you attempting to a nested list(list of strings) into the ssr function.

I believe a vector conditional like ?[x=100;0;x] would be much better suited to your needs. This function evaluates an if statement element wise on x, returning 0 where true and the original value where false.

fncol[`:.;`tab;`a;@[x;where x=100;:;0]]

Your lambda function can utilise amend in this case:
https://code.kx.com/q/ref/lists/#amend

I assume it is an integer column.
The above changes the value to 0 at indices where the current value is 100.

I would stress testing this thoroughly before applying to an important database.

In your function it looks like you are trying to replace a string values of 100 with integer values of 0. You will find this will be difficult because if your starting list is a list of strings, kdb will not let you just change some of the values to a different type.

q)l:("a";"b";"c")
q)l[0]:1
'type
 [0] l[0]:1
 ^
q)l[0]:"d"
q)l
"dbc"

Also "i"$"0" will convert the string to an integer type, whereas "I"$"0" will parse the text inside "0" into an integer value. In reality this means that "i"$"0" will become 48i as "0" is 48 in ASCII instead of 0.

If after you get the type error and get thrown into debug mode (indicated by multiple brackets at the q prompt) you can use functions .z.ex and .z.ey to see the failing function and arguments which may make it easier to debug