append new information in csv files to existing historical qvd

Question

Let's say I have a "master" qvd file named salesHistory.qvd, and I want to append new monthly sales from file salesMarch.csv

How do I do that without replacing existing information, but adding new months?

Thanks for the help!

Answer 1

By default, QlikView automatically appends table loads to a previously loaded table if the fields are identical. You can use this to your advantage by using a script similar to the following:

SalesHistory:
LOAD 
     *
FROM
[salesHistory.qvd] (qvd);

LOAD 
     *
FROM
[salesMarch.csv]
(txt, utf8, embedded labels, delimiter is ',', msq);

STORE SalesHistory INTO [salesHistory.qvd] (qvd);

This initially loads the contents of your salesHistory.qvd file into a table, and then loads the contents of salesMarch.csv and concatenates it into the SalesHistory table (which contains the contents of salesHistory.qvd.

The final STORE step saves this concatenated table into the salesHistory.qvd file by overwriting it completely.

In the above example, we use * as a field specifier to load all fields from the source files. This means that this approach only works if your QVD file contains the same fields (and field names) as your CSV file.

Furthermore, as this script loads the contents of the QVD file each time it is executed, it will start to duplicate data if it is executed more than once per month as there is no determination of which months already exist in the QVD file. If you need to execute it more than once per month (perhaps due to adjustments) then you may wish to consider applying a WHERE clause to the load from salesHistory.qvd so that only data up to and including the previous month is loaded.

Finally, you may wish to alter the name of your CSV file so that it is always the same (e.g. salesCurrentMonth.csv) so that you do not have to change the filename in your script.