SAP BI is technical + functional. Because the people u meet are those high/top management. u will meet sales director, logistics manager, orang besar that need to view the performance of the company. Bare in mind these ppl know nuts about IT, all they know is KPIs, business oeprations, business terms, business requirements, LAW & VATs. You must speak business language to them (hence u must KNOW functional/business processes). And these people are lazy, they want those business reports to go directly to their BB,SMS,email. they want everyday 9am the sales performance report is on their desk (either the secretary run the report then print out put on their table) or they received the report in PDF email or appear in their bb or hp (SMS).

2 parts of SAP BI
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front-end reporting : these people are 80% functional ppl who talk functional business language to users(managers). they understand R3 business processes very well, and the t-codes. 20% are with BO or BEX designer.

technical modelling: these people design the cube modeling/architecture of the datawarehouse. from design to ETL to performance tuning. without these stuff in place, reporting is not possible. they just need to understand how the tables are mapped in R/3.

SAP R/3 = the OLTP system for SAP, while SAP BI is the OLAP system