topic Re: LOAD empty QVD in App Development

LOAD empty QVD

muz_tim — Thu, 20 Jun 2024 22:35:27 GMT

Hi @all

I am trying to load a qvd but only retain the columns and empty out the table
The code below works but it reads all the data first then drop then it. but is proving time consuming because of the size of the QVD 15gb.

LOAD * FROM $(QVD_File) #this is variable that points to the qvd file WHERE 1=0;

Is there a more efficient way of pulling just the columns similar to df.columns in python

df.columns

Re: LOAD empty QVD

marksouzacosta — Fri, 21 Jun 2024 00:20:17 GMT

Not sure if this is most elegant way, but following my suggestion. You just need to replace the variables vTableName and vQVDFilename.

SET vTableName = 'CUSTOMER_NEW'; SET vQVDFilename = 'lib://DataFiles/CUSTOMER_NEW.qvd'; [TempLoadStatement]: LOAD CONCAT([FieldName],',') AS [LoadStatement] FROM [$(vQVDFilename)] (XmlSimple, table is [QvdTableHeader/Fields/QvdFieldHeader]) ; LET vLoadStatement = FieldValue('LoadStatement',1); [$(vTableName)]: LOAD * INLINE [ $(vLoadStatement) ]; STORE [$(vTableName)] INTO [$(vQVDFilename)](qvd); DROP TABLES [TempLoadStatement], [$(vTableName)] ;

Re: LOAD empty QVD

muz_tim — Wed, 26 Jun 2024 15:33:05 GMT

Thanks