topic Re: Data storing in QVD in App Development

Data storing in QVD

GOKULAKANNAN — Sat, 16 Oct 2021 11:00:24 GMT

My source is DB, where i will have all the record, if i have an item abc ,in which modified date as today, and tomorrow if its modified then new record will get created, but it wont replace the older one...so for an item we will have 2 records and while loading the data in qvd we need to get the latest one...but during the load the old record has already has been updated in qvd. How can i replace that with the new one.

Thank you

How can i acheive that?

Re: Data storing in QVD

stevejoyce — Sat, 16 Oct 2021 13:54:32 GMT

Take a look at incremental loading examples.

Loading new and updated records with incremental load ‒ Qlik Sense on Windows

This is a case of updated data.

You load your new/modified data first, but should only concatenate from qvd, where your key does not exist.

QV_Table:

SQL SELECT PrimaryKey, X, Y FROM DB_TABLE

WHERE ModificationTime >= #$(LastExecTime)#;

Concatenate LOAD PrimaryKey, X, Y FROM File.QVD

WHERE NOT Exists(PrimaryKey);

STORE QV_Table INTO File.QVD;

Re: Data storing in QVD

GOKULAKANNAN — Sat, 16 Oct 2021 14:42:32 GMT

Hi ,

thanks for the reply,

for example:

I'm having 4 rows of data like below

Item	country	Modified date
1234	India	27-07-2020
3456	Canada	28-07-2020
5676	USA	30-07-2020
7890	Canada	01-08-2020

on first reload the above data will be saved in qvd. now the update will be like addition of 2 rows within that one is a new record another one is as same as old record but only modified date will get change(last row)

Item	country	Modified date
1234	India	27-07-2020
3456	Canada	28-07-2020
5676	USA	30-07-2020
7890	Canada	01-08-2020
9876	Sweden	01-09-2020
1234	India	28-07-2020

Now in the last row the record is same , only change is modified date, in this case if we do concatenate it will add all the rows and it will save it in qvd, but I want to delete the existing record and add the new record and save it in qvd. how can I achieve this?

Re: Data storing in QVD

stevejoyce — Sat, 16 Oct 2021 23:15:02 GMT

//load data

data:

load *
from data_source
;

//limit to just current row for each item id

inner join (data)
load

Item,max([Modified date]) as [Modified date]
resident data
group by Item;