Empty table declaration

[Q_developer]

Hi ,

 

I have declared an empty table as t:([] c1:`int$();c2:`int$())

Now I want to insert compound column data like

c1     c2

--       ---

10     20 30

the statement `t insert (10; 20 30) didn't work.But if I declare the table without specifying null list of the type,then it is working.

i.e  t:([] c1:`int$();c2:()) works.

Is there any way to fix the type for the columns of the general lists before inserting first item.

 

Regards,

[Charles Skelton]

no, () is an empty list with type 0 - there's no way to embed the type of a nested list there.

Also note that

meta t

will take the type of the first element, and assume that the remaining elements are of the same type as that element; this is not always correct. e.g.

q)meta ([]a:(1 2;`a`b))

c| t f a

-| -----

a| J 

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[Sean]

there is a hacking way I am using, leave it to be general list when
firstly define the table, and then insert a sample data. in that way,
q will recognize the table schema by checking the first record.

here "I" means list of integers, this can be applied to "C" (string)
as well

q)a:([]c1:`int$();c2:())
q)insert [`a; (1;1 2)]
,0
q)meta a
c | t f a
--| -----
c1| i
c2| I
q)

[Felix Lungu]

that's no hacking. it is the way to define a column with nested data.