kdb ticker plant: where to find documentation on .u.upd?

kdb, q-lang

Solution

`.u.upd` has the same function signature as `insert` (see http://code.kx.com/q/ref/qsql/#insert) in prefix form. In the most simplest case, `.u.upd` may get defined as `insert`.

so: `.u.upd[`table;<records>]`

For example:

q).u.upd:insert
q)show tbl:([] a:`x`y;b:10 20)
   a b
   ----
   x 10
   y 20
q).u.upd[`tbl;(`z;30)]
   ,2
q)show tbl
   a b
   ----
   x 10
   y 20
   z 30
q).u.upd[`tbl;(`a`b`c;1 2 3)]
   3 4 5
q)show tbl
   a b
   ----
   x 10
   y 20
   z 30
   a 1
   b 2
   c 3

Problem

I am aware of this resource. But it does not spell out what parameters `.u.upd` takes and how to check if it worked. This statement executes without error, although it does not seem to do anything: ``` .u.upd[`t;(`$"abc";1;2;3)] ``` If I define the table beforehand, e.g. ``` t:([] name:"aaa";a:1;b:2;c:3) ``` then the above `.u.upd` still runs without error, and does not change `t`.

Original source