topic Re: Data loading from DB to QVD in QlikView

Data loading from DB to QVD

Thu, 30 Jan 2014 11:28:11 GMT

how data is read from data source( database) and write in qvd i.e row by row or bulk of data ?

Re: Data loading from DB to QVD

alexandros17 — Thu, 30 Jan 2014 11:36:07 GMT

AAA:

load * from myDB;

Store * from AAA intomyFile.qvd

Re: Data loading from DB to QVD

Thu, 30 Jan 2014 11:36:43 GMT

Bulk of data.

A qvd file is a table. QlikView first extract all rows and tables from DB and then stores the tables into qvd files.

Re: Data loading from DB to QVD

Thu, 30 Jan 2014 12:37:32 GMT

Hi Mario, thanks for reply............

suppose if we have something as below

table:

load * from table where condition ;

Store * from table into table.qvd(qvd)

Then while executing the query it will fetch all records at one time satisfying the condition and then only it will get data and store in qvd.

it won't check individual row and write qvd each time.

Am I correct....

Please correct me if I am going wrong

Re: Data loading from DB to QVD

jonathandienst — Thu, 30 Jan 2014 12:49:14 GMT

There is a difference between the way QV handles a SQL SELECT (from a database) and a LOAD(from Excel, text file or resident table). QV does not document how the SQL select works, I suspect that this is determined by the ODBC or OLE DB provider, rather than QV.

As far as I know, the LOAD statement works line-by-line and not bulk. This is what allows us to use options such Previous, Peek and Exists

HTH

Jonathan

Re: Data loading from DB to QVD

Thu, 30 Jan 2014 13:04:22 GMT

hi,

what I want to know is while reading data from DB to qvd using

selecting * from table

it will get bulk of data or row by row from database to qvd

Thanks

Re: Data loading from DB to QVD

alexandros17 — Thu, 30 Jan 2014 13:06:14 GMT

"While" is not possible, you have to end a process to start another

Re: Data loading from DB to QVD

jonathandienst — Thu, 30 Jan 2014 13:06:43 GMT

Charan korikuppa wrote:

what I want to know is while reading data from DB to qvd using

selecting * from table

it will get bulk of data or row by row from database to qvd

...QV does not document how the SQL select works, I suspect that this is determined by the ODBC or OLE DB provider, rather than QV...

Re: Data loading from DB to QVD

Thu, 30 Jan 2014 13:11:25 GMT

Hi Charan,

Yes, QV will first execute the Load statement and build up the table before it will move on to the STORE statement to store the table. So QV won't check "won't check individual row and write qvd each time".

Regards,

Stefan