topic hash128() without knowing the number of fields in QlikView

hash128() without knowing the number of fields

Wed, 25 Nov 2020 16:16:04 GMT

Hi all,

I am trying to apply hash128() function on loaded records but I don't really know the name of the loaded fields neither their number .

Besides , the number of the fields is variable .

I tried hash128(*) but it doesn't work. Is there any possible way to solve this problem?

Thank you,

Re: hash128() without knowing the number of fields

adamdavi3s — Thu, 09 Mar 2017 09:58:49 GMT

I think we need to know a bit more about what you're trying to do here.

Hash128 is usually used to create a composite key of a number of known fields because it is smaller and faster than a concatenate of the fields

Re: hash128() without knowing the number of fields

swuehl — Thu, 09 Mar 2017 10:03:33 GMT

You can use system functions to query the name and number of fields in a table.

Iterate over the field names and create variable with a concatenated string of your field names, then expand the variable in your hash128() function as argument.

System functions (from the help).

NoOfFields([ 'TableName ' ])

Returns the number of fields in a previously loaded table.

Examples:

LET a = NoOfFields('tab1');

Load *, NoOfFields( ) from abc.csv;

FieldName(nr ,'TableName')

Returns the name of the field with the specified number within a previously loaded table.

If the function is used within a load statement, it must not reference the table currently being loaded.

Examples:

LET a = FieldName(4,'tab1');

T1:
Load a, b, c, d from abc.csv
T2:
Load FieldName (2, 'T1') Autogenerate 1;

Re: hash128() without knowing the number of fields

Peter_Cammaert — Fri, 10 Mar 2017 16:11:45 GMT

Example using QVD file here: Re: How to apply a hash function to all fields

That's almost a circular reference in discussions