What is the role of SAP BW?

Hello. Trying to understand the basic SAP tools. I do not quite understand the role of the SAP BW(hereafter BW).
BW is a database, that is, it is permanently stored all information and SAP ERP only collects information? Or not?5b53801bbfae0032927652.jpegJudging by this picture of BW is an aggregator, that is just the Manager of the information stored in the database. 5b5380fa4c631829214681.jpeg But in this picture the role of the DB and BW are swapped(their order in the chain). So what is the essence of BW and how it takes place?
June 3rd 19 at 19:02
2 answers
June 3rd 19 at 19:04
the aggregation and adaptation of the incoming data
That is, the correct topology is listed in the first picture? - delia25 commented on June 3rd 19 at 19:07
on both

the report not only he can build - Juanita17 commented on June 3rd 19 at 19:10
got it, thanks.
And one more question(possibly stupid)):
Is there a tool with the acronym SSDR, which could serve as:
Used as a hub for the exchange of data between systems and as the main reportinga system - delia25 commented on June 3rd 19 at 19:13
June 3rd 19 at 19:06
Yeah... advertising bulletcam marketers you will long to understand.
Better Google.
Right first conclusion:
SAP BW is a platform that allows you to store huge amounts of business information and use it to analyze the situation and make informed management decisions.

Actually this is the essence. BI stored and analyzed (different angles) then show the big boss what happened. However, not necessarily big.

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