Databases Reference
In-Depth Information
The way the data flows
While the in-memory database is excellent technology, it cannot function on its own.
Functionally, data flows through QlikView in the following manner (also shown in
the following image):
1.
It starts with the source data. QlikView can load data from a large variety of
sources, including
ODBC
,
OLEDB
,
Flat Files
(Excel, CSV, and so on), and
XML
. There are also many different connectors, ranging from big enterprise
applications such as SAP, to social networks such as Twitter.
2.
The data is loaded into QlikView using a load script. This script can be used
to extract, transform, and load data into the in-memory data model or to
store it to the disk in intermediary data files called
QVD files
.
3.
Data in the in-memory database is stored in an unaggregated format,
meaning all aggregations are calculated on the fly. This simplifies data
modeling in QlikView, as there is no need for separate aggregation tables.
4.
Selections made by the user automatically cascade throughout the entire data
model and these changes are shown by QlikView's presentation engine.
5.
QlikView applications can be presented in multiple clients. The Windows
application we used earlier is an example of a client; other similar examples
will be covered in the next section.
