151.
What
are data-marts?
Data
Marts are used to exchange data between different BW systems or to
update data within the same BW system (Myself Data Mart). Here, the
InfoProviders that are used to provide data are called Data Marts.
152.
Which
one is more normalized; ODS or InfoCube?
InfoCube
is more normalized than ODS.
153.
What
is replication of DataSource?
Replication
of DataSource enables the extract structure from the source system to
be replicated in the BW.
154.
What
are the quality checks for inefficient InfoCube designs?
Huge
Dimension tables make an InfoCube inefficient.
The
query takes a long time.
155.
Why
is star schema not implemented for ODS as well?
Because
ODS is meant to store a detailed document for quick use and help make
short-term decisions.
156.
Why
do we need separate update rules for characteristics on each key
figure?
If
the requirement specifies a different need for each characteristic
then we have separate update rules for each of the characteristics.
157.
What
is the use of Hierarchies?
Efficient
reporting is one of the targets of using hierarchies. Easy drilldown
paths can be built using hierarchies.
158.
What
is "Referential Integrity"?
A
feature provided by relational database management systems (RDBMS)
that prevents users or applications from entering inconsistent data.
For example, suppose Table B has a foreign key that points to a field
in Table A.
o
Referential
integrity would prevent from adding
a record to Table B that cannot be linked to Table A.
o
Referential
integrity rules might also specify that whenever you delete
a record from Table A, any records in Table B that are linked to the
deleted record will also be deleted. This is called cascading delete.
o
Referential
integrity rules could specify that whenever you modify
the value of a linked field in Table A, all records in Table B that
are linked to it will also be modified accordingly. This is called
cascading update.
159.
What
is a Transactional InfoCube and when is it preferred?
Transactional
InfoCubes differ from Basic InfoCubes in their ability to support
parallel write accesses. Basic InfoCubes are technically optimized
for read accesses to the detriment of write accesses. Transactional
InfoCubes are designed to meet the demands of SEM, where multiple
users write simultaneously into an InfoCube.
160.
When
is data in Change Log table of ODS deleted?
When
requests loaded into ODS object are neither required for delta update
nor for initialization, they can be deleted. If delta initialization
for update exists in connected data targets, the requests have to be
updated first before the data can be deleted.
161.
How
is the data of different modules stored in R/3?
Data
is stored in multiple tables in R/3 based on ERM (Entity Relationship
model) to prevent the redundant storage of data.
162.
In
what cases do we transfer data from one InfoCube to another?
Modifications
can't be made to an InfoCube if there is data present in the
InfoCube. If we want to modify an InfoCube and no backup for data
exist then we can design another InfoCube with the parameters
specified and load data from the old InfoCube.
163.
How
often do we have a Multi-layered structure in ODS stage and in what
cases.
Multi-layered
structure in ODS stage is used to consolidate data from different
DataSources.
164.
How
is data extracted from systems other than R/3 and Flat files?
Data
is extracted from systems other than R/3 and flat files using staging
BAPIs.
165.
When
do tRFC and IDoc errors occur?
tRFC
and iDoc errors- when you load data , these are connection specific
and if the source system is not set properly or is interrupted , you
get these errors.
Intermediate
Document (IDoc) is a container for exchanging data between R/3, R/2
and non-SAP systems. IDocs are sent in the communication layer by
transactional Remote Function Call (tRFC) or by other file interfaces
(for example, EDI). tRFC guarantees that the data is transferred once
only. Was not able to find out when the errors occur.
166.
On
what factors does the loading time depend on?
Loading
time depends on the work load both on the BW side and source system
side. It might also depend upon the network connectivity.
167.
How
long does it take to load a million records into an InfoCube from an
R/3 system?
Depending
on work load on BW side and source system side loading time varies.
Typically it takes half an hour to load a million records.
168.
Will
the loading time be same for the same amount of data for non-SAP
systems like Flat files?
It
might not be the same. It depends on the extraction programs used on
the source system side.
169.
What
is mySAP.com?
SAP
solution to integrate all relevant business processes on the
Internet. mySAP.com integrates business processes in SAP and non-SAP
systems seamlessly and provides a complete business environment for
electronic commerce.
170.
How
was Data modeling done in your project? Explain
Initially
we study the business process of client, like what kind of data is
flowing in the system, the volume, changes taking place in it, the
analysis done on the data by users, what are they expecting in the
future, how can we use the BW functionality. Later we have meetings
with business analyst and propose the data model, based on the
client. Later we give a proof of concept demo wherein we demo how we
are going to build a BW data warehouse for their system. Once we get
an approval we start requirement gatherings and building your model
and testing follows in QA.
171.
As
you said you have worked on InfoCubes and ODS, Which one is better
suited for reporting? Explain and what are the drawbacks and benefits
of each one?
Depending
on the type of report the data is stored in InfoCube or ODS. BW is
used to store high volumes of data and faster reporting. InfoCube is
used to store normalized data. Master Data and transaction data are
stored in InfoCube as per the Extended Star Schema using SIDs. The
reporting is fast.
ODS
stores data in more detail utilizing its structure of transparent
tables. Reporting on this will be slow. ODS is better used for RRI.
172.
How
do you measure the size of InfoCube?
In
number of records
173.
What
is the difference between InfoCube and ODS?
InfoCube
is structured as per Extended Star Schema with the fact table
surrounded by different dimension tables which connect to SIDs. And
the data can be aggregated in the InfoCubes. ODS is a flat structure
and does not use the star schema concept and has detailed data in
transparent tables.
174.
What
is the difference between display attributes and navigational
attributes?
Display
attribute is one which is used only for display purpose in the
report. Where as navigational attribute is used for drilling down in
the report. We don't need to maintain NAV attribute in the InfoCube
as a characteristic (that is the advantage) to drill down.
175.
Data
is uploaded twice into InfoCube. How to correct it?
You
can delete it by the Request ID.
176.
Can
you add a new field at the ODS level?
Yes.
177.
Can
many DataSources have one InfoSource?
Yes.
For example, for loading text and hierarchies we use different
DataSources but the same InfoSource.
178.
Apart
from R/3, which legacy db you used for extraction?
Access,
Informatica
179.
There
were problems with delta loads. The DataSources and transfer rules
were re-activated and transported from both DEV systems to the
Production systems. When the jobs are scheduled, there is an error
that the delta update to the InfoCube has been invalidated because a
previous delta load has been deleted from the InfoCube. All data from
the ODS objects and the InfoCube then ran the initialization of delta
job to restart the process has already been deeted. The load to the
ODS objects completes successfully but the subsequent load to the
InfoCube from the two ODS objects fails with this error.
Prior
to deleting all the data did you run the last deltas from the delta
collective runs into the InfoCube? It sounds as if you may have left
the delta data in the queue and re-initialized the delta process.
Thus when you go to load the delta data it doesn't want to load b/c
it is looking for it’s predecessor delta that you deleted.
180.
I
had initialized an LIS structure for billing and when I ran the delta
request it is giving me an error stating that this is a duplicate
document and my user wants the report urgently.
What
I did was,
o
Deleted
setup data (LBWG in R3)
o
Deleted
delta queue (RSA7 in R3)
o
Generated
new queue (for 2LIS_13_VDITM it is OLI9BW transaction)
181.
I
have a requirement in one of the existing InfoCube to change the
Attribute as Navigational. I am sure that I have to check the
Navigational option in the Attributes tab of respective
characteristic and I have to check the option in the InfoCube also.
My concern is, this InfoCube already has millions of records in
production, I wonder is there any way to realign it with out
reloading the InfoCube. How about realigning master data after making
those changes... Is it mandatory to reload the InfoCube or any work
around is available.
All
you need to do after selecting and activating the object and InfoCube
is run a Hierarchy attribute change run. That should make the Nav
attr. visible for reporting. In my first project I created an FI
InfoCube with the company info. customized the FI AR InfoCube and
created a MultiProvider for the users to drill down on customer info
and ledger accounts. I also customized the sales overview for
transactional data
182.
When
Extracting Sales Data using V3 Collective Run using LBWE job control,
no data is being extracted (Nothing is being shown in RSA3). When
filling up Setup Table for OLD Documents, we are able to see the
Extracted Data records in RSA3. What may be wrong? And what should be
the actual procedure to see data consistently in RSA3 so that BW can
pull records from R/3.
In
RSA7 on the source system do you see your DataSources under queue
maintenance and are they green? Also, did you run OLI7BW to setup
your data in the statistical queue for initialization? And finally
did you run your init from BW to initialize the delta process and get
the initial load into BW? If you have done all these things you
should be collecting deltas in the delta queue under RSA7.
183.
Where
the PSA data is stored?
In
PSA table.
184.
What
is data size?
The
volume of data one data target holds(in no. of records)
185.
Different
types of InfoCubes.
BasicCube,
Virtual
Cube
o
RemoteCube
o
SAP
RemoteCube
o
Virtual
InfoCube with services
186.
What
is an InfoSet?
InfoSet
is an intersection of multiple InfoProviders. They can be made of ODS
and InfoObjects only.
187.
If
there are two DataSources how many transfer structures are there?
Two
in R/3 and Two in BW
188.
What
are indexes?
Indexes
are database indexes, which help in retrieving data fast.
189.
Is
it necessary to initialize each time the delta update is used?
No
190.
After
the data extraction what is the image position?
After
image
191.
What
are Authorizations?
Profile
generators.
192.
Can
a Characteristic and InfoObject be InfoProvider?
Yes
193.
What
is data Integrity and how can we achieve this?
Data
Integrity is about eliminating duplicate entries in the database and
achieve normalization.
194.
What
is index maintenance and what is its purpose?
Indexing
is a process by which the address of data is stored. It helps easier
access to the data.
195.
When
and why use InfoCube compression?
When
the data in the InfoCube is not going to change ever and if it is
occupying a lot of space then we compress the InfoCube. The data that
is compressed cannot be altered or deleted except through selective
deletion, hence we have to make an informed decision on compression.
This compression can be done through process chain and also manually.
196.
How
can Business Content be enhanced? And why do we need to enhance the
Business Content?
We
can enhance the Business Content by adding fields to the Extract
Structures delivered by SAP BC. We may need to enhance the BC because
we need to provide fields which are not already in the BC as per the
customers needs. Eg: you have a customer InfoCube (in BC) but your
company uses attribute for say Apt number. Then instead of
constructing the whole InfoCube you can add the above field to the
existing BC InfoCube.
197.
What
is Tuning and why do we do it?
Tuning
is done to increase efficiency. It is done to lower time for:
o
Loading
data into Data Target
o
Accessing
a query
o
For
drilling down in a query, etc
198.
What
is a MultiProvider and how do we use MultiProvider?
MultiProvider
can combine various InfoProviders for reporting purposes. We can
extract data from an ODS, InfoCube, InfoSet, InfoObject, etc in any
combination.
199.
What
are scheduled and monitored data loads?
Scheduling
of data load means to schedule the loading of data for some
particular date and time. It can be done from the scheduler tab on
Create InfoPackage. Data Loads are monitored using transaction RSMON.
