Autonumber

[#1]

Hi Experts,

Can you clear my doubt in explaining the diffrence b/w

Autonumber(),

Autonumberhash128(),

Autonumberhash256()

In the help window of qlikview I gone through but not got clarity on this.

As per my understanding autonumber() is used for getting distinct unique values whenever there is a composite key needed. Since composite key consumes more memory we use Autonumber().But rest of the two functions also yields same. Only difference  which I can see here is that we write filed names separated by commas in contrast with autonumber as by & symbol.

Is there any specific difference please advice.

[#2 · Accepted solution]

hi

Autonumber needs one expression as input

and autonumberhashXXX can handle more inputs.

hence use autonumber(field1 & field2 & field3) which needs to calculate the concatenation of field1,-2 and -3 first. Autonumberhash can take more inputs: autonumberhash128(field1, field2, field3). More importantly the autonumberhash are likely more efficient in determining if the combined inputs have already been encountered or are encountered for the first time. So they are probably faster in calculating the unique integer.

[#3]

Thanks a lot.