A QVD (QlikViewData) file is a file containing a table of data exported from Qlik. QVD is a native Qlik Sense and Qlikview format and can only be written to and read by Qlik. The file format is optimized for speed when reading data from a Qlik Sense script but it is still very compact. Reading data from a QVD file is typically 10-100 times faster than reading from other data sources.
QVD files can be read in two modes, standard (fast) and super-fast. The selected mode is determined automatically by the Qlik script engine. Super-fast mode can be utilized only when all fields or a subset thereof are read without any transformations (formulas acting upon the fields), though the renaming of fields is allowed.
- A QVD file holds exactly one data table and consists of three parts:
A well formed XML header (in UTF-8 char set) describing the fields in the table, the layout of the subsequent information and some other meta-data.
- Symbol tables in a byte stuffed format.
- Actual table data in a bit-stuffed format.
Purpose of QVD Files
- Reduce the need for requests for data across a network.
- Speed up load time
- Replacing a data warehouse
- Transformation steps
- Incremental Loading
- Creating a standard data model to be used across Qlik Sense applications
- Consolidating data from many Qlik Sense applications
Creating a QVD File
Basically just put this in the script editor…
STORE [QlikTableName] INTO newqvdname.qvd(qvd);
Remember you will need to have a directory set up. If you use it like this above it will store the QVD in exactly the same place as the QVF file. This is the same behaviour for local Qlik Sense and on the Server.
How to read a QVD File
It’s best just to think of a QVD file in Qlik Sense as just another table. You access it the same way you would access a table in Excel. Find it in the folder its stored in and click on it..