Will They Blend? Theobald Meets HANA

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Click to learn more about author Maarit Widmann.

In the “Will They Blend?” blog series, we experiment with
the most interesting blends of data and tools.

Whether it’s mixing traditional sources with modern data lakes, open-source devops on the cloud with protected internal legacy tools, SQL with noSQL, web-wisdom-of-the-crowd with in-house handwritten notes, or IoT sensor data with idle chatting, we’re curious to find out: Will they blend? Want to find out what happens when IBM Watson meets Google News, Hadoop Hive meets Excel, R meets Python, or MS Word meets MongoDB?

Read the previous blog in the series here.

Today’s challenge: Blend data
on a SAP system that is accessed in two ways

1. The legacy way – via the JDBC
driver of the database, SAP HANA, for example, and 

2. The new way – via the Theobald Xtract Universal Server

The legacy way requires a few steps: registering the JDBC
driver of the SAP HANA database in KNIME, connecting to the database with the
DB Connector node, selecting a table on the connected database, and reading it
into the database. Using the SAP integration available from the Analytics
Platform version 4.2 forward, you can access and load SAP data just by one node
called SAP Reader (Theobald). 

In our example, we extract KPIs from orders data, and show their development over time. We access the data about the submitted orders the legacy way. The data about the features of the ordered items are available on the Theobald Xtract Universal Server, so we read this data with the SAP Reader (Theobald) node. We connect to both systems from within the platform, join the data on the sales document key column available in both tables, and show the historical development of a few KPIs in an interactive dashboard: Is the number of orders increasing over time? What is the most popular product per year? Let’s take a look!

Figure 1: Accessing SAP data via Theobald (new) and via the JDBC driver of the SAP HANA database (legacy) before blending and preprocessing the data, and calculating and visualizing KPIs in the Analytics Platform.

Challenge: Access
SAP data via Theobald and via the JDBC driver of the SAP HANA database 

Topic: Calculate
KPIs of orders/items data and visualize the historical development of the KPIs
in an interactive dashboard

Access Mode: Connect
to Theobald Xtract Universal Server and to SAP HANA database

Integrated Tools: SAP,
Theobald

The
Experiment

The workflow in Figure 2 shows the steps in accessing the
SAP data via Theobald (top branch) and via the JDBC driver of the database
(bottom branch). The data for this experiment is stored in the Sales Document: Item Data and Sales Document: Header Data tables included in SAP ERP.
After accessing the data, we join the tables, and extract year and month from
the timestamps in order to calculate the KPIs at a meaningful granularity.
Next, we calculate four different KPIs: total number of orders per month,
average number of orders per month, average net weight of an order in each month,
and the most popular product in each year. The KPIs are shown in the
interactive view of the KPI Dashboard component (Figure 3).

Figure 2: A workflow to access SAP data via Theobald and via the JDBC driver of the SAP HANA database, and to blend and preprocess data before calculating and visualizing KPIs in an interactive dashboard.

Accessing Theobald Xtract Universal Server

We want to access the “Sales Document: Item Data” table that
contains detailed information about item orders (each row contains details of a
specific item of an order) and is accessible via the Theobald Xtract Universal
Server. The server provides a so-called table extraction feature where we can
extract specific tables/views from various SAP systems and store them as “table extraction” queries. The SAP Reader
(Theobald) node is able to connect to the given Xtract Universal Server to
execute those queries and import the resulting data.

1. Open the configuration dialog of
the node, and enter the URL to the Theobald Xtract Universal Server. Click
the Fetch queries button to fetch all available extraction
queries on the server. We can then select one query from the drop-down list. In
our case it is the “Sales Document: Item Data” table. Note that it is necessary
to provide SAP credentials in the authentication section if the selected query
is connected to a protected SAP system. 

2. Executing the node will execute
the selected query on the Xtract Universal server and imports the data into a
table. 

Accessing SAP HANA

We want to access the “Sales Document: Header Data” table
that contains information about the submitted orders and is available on the
SAP HANA database on a locally running server. We can access the database, like
any other JDBC-compliant database that doesn’t have a dedicated connector node,
with the DB Connector node. In the configuration dialog of the DB Connector
node, we can select the JDBC driver of an arbitrary database in the Driver Name
field. In order to make our preferred database SAP HANA show in the Driver Name
menu, we need to register its JDBC driver first.

  1. To register a JDBC driver, go to File → Preferences →
    KNIME → Database. The driver (.jar file) is installed as part of the SAP HANA client
    installation. To find where the JDBC driver
    is located, please check the SAP HANA
    documentation. Then we can add it to KNIME
    by following the steps described here in the Database
    Extension Guide.
  2. After registering the JDBC driver, open again the
    configuration dialog of the DB Connector node, select the newly registered
    JDBC driver in the menu, for example, sap: [ID: sap_id], and specify the
    database URL, for example, jdbc:sap://localhost:39015. Also provide the
    credentials with one of the authentication methods.
  3. The connection to the SAP HANA database is now created.
    Continue with the DB Table Selector node to select a table on the database
    and the DB Reader node to read the data into a table.

Blending Data and Calculating
the KPIs

After accessing the two tables, we join them on the sales
document key (VBELN column), and get a table that contains information on both
the submitted orders and the items included in each order. Since the current
granularity of the data is daily, and the time range of the data reaches from
January 1997 to May 2020, we aggregate the data at a monthly level before
calculating the KPIs. 

Results

The interactive view output of the KPI Dashboard component
(Figure 3) visualizes the KPIs. In the line plot in the top left corner we can
see that the average number of orders per month was the highest at the
beginning of 2000, and since 2014 it stagnates at a relatively low level. Yet
in the past there were some quieter periods followed by periods with more
orders, for example, the low around 2008 followed by a peak around 2013. We can
find a similar kind of pattern in the line plot in the top right corner that
shows in addition the total number of orders per month. 

In the tile view in the bottom left corner, we can browse through the most popular products for each year. And finally, in the line plot in the bottom right corner, we can see that the ordered items have become lighter over time, or the orders contain fewer items than before and have therefore less weight. An especially remarkable decrease in the average weight of an order happened around 2014. 

Figure 3: Interactive dashboard visualizing the KPIs that were calculated after accessing and blending the orders/items data available as SAP tables.

Do They or Don’t They?

In the dashboard shown in Figure 3, the product names and
weights come from the “Sales Document: Item Data” table, accessed via Theobald
Xtract Universal Server, whereas the order counts come from the “Sales
Document: Header Data” table, accessed via the JDBC driver of a SAP HANA
database.

All this information can be visualized in one dashboard, so
yes, they blend!

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