Quick Tips: Time Dimension with Time Bands at Seconds Granularity in Power BI and SSAS Tabular

Time Dimension with Time Bands at Seconds Granularity in Power BI and SSAS Tabular

I wrote some other posts on this topic in the past, you can find them here and here. In the first post I explain how to create “Time” dimension with time bands at minutes granularity. Then one of my customers required the “Time” dimension at seconds granularity which encouraged me to write the second blogpost. In the second blogpost though I didn’t do time bands, so here I am, writing the third post which is a variation of the second post supporting time bands of 5 min, 15 min, 30 min, 45 min and 60 min while the grain of the “Time” dimension is down to second. in this quick post I jump directly to the point and show you how to generate the “Time” dimension in three different ways, using T-SQL in SQL Server, using Power Query (M) and DAX. Here it is then:

Time Dimension at Second Grain with Power Query (M) Supporting Time Bands:

Copy/paste the code below in Query Editor’s Advanced Editor to generate Time dimension in Power Query:

let
Source = Table.FromList({1..86400}, Splitter.SplitByNothing()),
    #"Renamed Columns" = Table.RenameColumns(Source,{{"Column1", "ID"}}),
    #"Time Column Added" = Table.AddColumn(#"Renamed Columns", "Time", each Time.From(#datetime(1970,1,1,0,0,0) + #duration(0,0,0,[ID]))),
    #"Hour Added" = Table.AddColumn(#"Time Column Added", "Hour", each Time.Hour([Time])),
    #"Minute Added" = Table.AddColumn(#"Hour Added", "Minute", each Time.Minute([Time])),
    #"5 Min Band Added" = Table.AddColumn(#"Minute Added", "5 Min Band", each Time.From(#datetime(1970,1,1,0,0,0) + #duration(0, 0, Number.RoundDown(Time.Minute([Time])/5) * 5, 0))  +  #duration(0, 0, 5, 0)),
    #"15 Min Band Added" = Table.AddColumn(#"5 Min Band Added", "15 Min Band", each Time.From(#datetime(1970,1,1,0,0,0) + #duration(0, 0, Number.RoundDown(Time.Minute([Time])/15) * 15, 0))  +  #duration(0, 0, 15, 0)),
    #"30 Min Band Added" = Table.AddColumn(#"15 Min Band Added", "30 Min Band", each Time.From(#datetime(1970,1,1,0,0,0) + #duration(0, 0, Number.RoundDown(Time.Minute([Time])/30) * 30, 0))  +  #duration(0, 0, 30, 0)),
    #"45 Min Band Added" = Table.AddColumn(#"30 Min Band Added", "45 Min Band", each Time.From(#datetime(1970,1,1,0,0,0) + #duration(0, 0, Number.RoundDown(Time.Minute([Time])/45) * 45, 0))  +  #duration(0, 0, 45, 0)),
    #"60 Min Band Added" = Table.AddColumn(#"45 Min Band Added", "60 Min Band", each Time.From(#datetime(1970,1,1,0,0,0) + #duration(0, 0, Number.RoundDown(Time.Minute([Time])/60) * 60, 0))  +  #duration(0, 0, 60, 0)),
    #"Removed Other Columns" = Table.SelectColumns(#"60 Min Band Added",{"Time", "Hour", "Minute", "5 Min Band", "15 Min Band", "30 Min Band", "45 Min Band", "60 Min Band"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Removed Other Columns",{{"Time", type time}, {"Hour", Int64.Type}, {"Minute", Int64.Type}, {"5 Min Band", type time}, {"15 Min Band", type time}, {"30 Min Band", type time}, {"45 Min Band", type time}, {"60 Min Band", type time}})
in
#"Changed Type"
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Quick Tips: Time Dimension with Granularity of Seconds in Power BI and Analysis Services Tabular Models

Quick Tips: Time Dimension with Granularity of Seconds in Power BI and Analysis Services Tabular Models
Photo by Markus Spiske

In an article I posted a while back I showed different methods of creating Time dimension in Power BI and Tabular models. The Time dimension I explained was in Minutes. In this post I show you simple way to create Time dimension supporting Seconds. As this is a quick tip, I only show you how to get the Time and ID columns in the Time dimension. If you need to add time bands (time buckets) check this out for more details.

Time Dimension in Seconds Grain with Power Query (M):

Copy/paste the code below in Advanced Editor to generate Time dimension in Power Query:

let
Source = Table.FromList({1..86400}, Splitter.SplitByNothing()),
#"Renamed Columns" = Table.RenameColumns(Source,{{"Column1", "ID"}}),
#"Time Column Added" = Table.AddColumn(#"Renamed Columns", "Time", each Time.From(#datetime(1970,1,1,0,0,0)+#duration(0,0,0,[ID]))),
#"Changed Type" = Table.TransformColumnTypes(#"Time Column Added",{{"ID", Int64.Type}, {"Time", type time}})
in
#"Changed Type" 
Time Dimension in Power Query

Time Dimension in Seconds Grain with DAX:

Run the DAX expression below in a new calculated Table in Power BI or SSAS Tabular model:

Time in DAX = ADDCOLUMNS(
                       GENERATESERIES(1, 86400, 1)
                        , "Time", TIME(0, 0, 0) + [Value]/86400
                        )
Time Dimension in Seconds Level with DAX
Continue reading “Quick Tips: Time Dimension with Granularity of Seconds in Power BI and Analysis Services Tabular Models”

Time Dimension in Power BI and SSAS Tabular Model Supporting Minutes Time Bands

2018-05-23 12_58_48-Symbols (Open in Visio).vsdx - Visio Professional

Date dimension has been discussed quite a lot on the Internet and you can find lots of valuable articles around it here and there. But what if you need to analyse your data in time level? A customer has a requirement to analyse their data in Minutes level. This means that the granularity of the fact table would be at minute level. So, if they store the data in their transactional database in seconds level, then we need to aggregate that data to minutes level. I don’t want to go there, just bear in mind that the granularity of your fact table is something that you must think about at the very first steps. In most cases, if not all cases, you’d be better to have a separate Time dimension. Then you need to have a TimeID or Time column in your fact table to be able to create a relationship between the Time dimension and the fact table. In this post I show you two ways to create Time dimension in Power BI:

  • Creating Time dimension with DAX
  • Creating Time dimension with Power Query (M)

Alternatively, you can take care of the Time dimension in the source system like SQL Server. Continue reading and you’ll find a T-SQL codes as complementary.

The techniques that I explain here can be done in SSAS Tabular model and Azure Analysis Services as well.

Requirements:

To follow the steps of building the test model you need to have:

  • Power BI Desktop: Download the latest version from here
  • A sample fact table containing time or datetime. I modified FactInternetSales from AdventureWorksDW and made it available for you to download in Excel format (find the download link at the bottom of the post)

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Side-by-side Role-Playing Dimensions In Power BI

Role-playing dimension is one those concepts that is discussed a lot from time to time. I also posted an article about implementing role-playing dimensions in Tabular models.

To recap, in the role playing dimensions in SSAS Tabular article I explained three different solutions:

  1. Importing role playing dimensions several times into the model
  2. Creating database views in the source side (in case your source is a from of RDBMS like SQL Server, Oracle etc…) then import the data into the model
  3. Keep the inactive relationships in the model and create several measures to take care of different roles using USERELATIONSHIP functions in DAX

I this post I explain implementation of the third option above. In this scenario you need to create especial calculated measures based on the roles you have in a fact table. One the most common role-playing dimensions is Date dimension. Consider you have to show Internet Sales Amount by Order Date, Due Date and Ship Date in a single chart in your report. In this case, having 3 different date tables won’t help us to achieve the goal.

New to Power BI? Quickly learn about Data Visualisation in Power BI here.

Defining new Measures in Power BI Desktop

Basically, what I’m going to explain in this post is using inactive relationships between FactInternetSales table and the DimDate dimension by adding a new Calculated measure. In this case, we’ll be able to show Sales Amount by different roles, well, dates in this sample in a single chart.

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