What is grain of a table in data warehousing

In simple terms grain is the lowest level till which you could identify the data in a table.
For example: If you have table which holds the stock inventory and table holds:

1. One record for each day of the stock : Than the grain would be one day
2. One record for each hour : than the grain of the table would be hour
3. One record for each week : than the grain of the week would be week.

How does grain impacts the data warehouse:
It is important that while designeing the databse we design till the lowest grain for which we business needs to analyse or report.
With example above, If your Stock inventory table has grain of day you can easily calculate weekly stock but viceversa is not true.

Similarly, grain of related tables(Facts and Dims) should complement each other. For eg if Fact_Stock_Inventory holds data for each hour and Dim_DateTime has a grain of a day, it will generate distorted results.

Power BI On-premises Report Server

We all know Microsoft launched Power BI in 2014 as a cloud based service only with per user licence. Since than Power BI has evolved a lot. Let it be Customer Visualisations, Power Bi Gateway or Power Bi embedded it is much better than before.
Today we are going to talk about Power Bi Report Server. It was a constant demand from microsoft to provide Power BI as an intranet tool, because not everyone is comfortable is pushing there data/reports on the cloud.

So, in last quarter of 2017 Microsoft launched an on-Premesis report server for power BI  called Power Bi Report Server. It has been developed on the existing SSRS server, so if you have used the SSRS server before you will find it pretty similar.
I am not going to go into installation steps because that's pretty neatly done here.
Follow the steps and you would be able to install and configure the server. If you still find any problems feel free to post in the comments below.

Once you have configured thePower BI server and database, it will look like this. I looks exactly the same as SSRS report server

The new tab we noticed here(different from SSRS server) is the "Power Bi Service Cloud". If you have a power BI service account wth premium licence, you could take advantage if hybridoption. Microsoft has released this option to smooth transition of on-prem customers to cloud.
To create a new report you would need to download the Power Bi Desktop version for Report Server. Microsoft has released 2 separate versions of PBI desktop for Power BI Services and Power Bi On-Prem. Hopefully they will merge it later.