This presentations shows how to create a time/date dimension for PowerPivot from the date data in your fact table. I also shows the DAX functions that you can use to add columns to the fact table or a separate dimension table.

1. Michael P. Antonovich
Blog: http://SharePointMike.WordPress.com
IT PRO Camp Jacksonville 2012

2. • User’s Guide to the Apple ][ - 1983
• FoxPro 2 Programming Guide – 1992
• Debugging and Maintaining FoxPro – 1992
• Using Visual FoxPro 3.0 – 1995
• Using Visual FoxPro 5.0 – 1996
• Office and SharePoint User’s Guide – 2007
• Office and SharePoint User’s Guide – 2010
Speaker at:
Code Camp 2009, 2010, 2011, 2012 Orlando
SharePoint Saturday 2011 Tampa, 2012 Orlando
SQL Saturday - #1, #4, #8, #10, #15, #16, #21, #32, #38, #49, #62, #74, #79, #85,
#86, #110, #130
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3. • Aggregate – A mathematical function that allows you to
summarize values of an attribute
• Dimension - A dimension is essentially a look-up table that
may define a hierarchy or drill-down path such as Year >
Quarter > Month
• Measure – A measure is something that identifies a value
• Fact – A fact is another term for a measure that contains
numeric data that can be grouped along one or more
dimensional hierarchy
• Star Schema – All dimension tables radiate out from a single
fact table
• Snowflake Schema – One fact table may relate to another fact
table before relating to dimension tables. One dimension table
can also have a related dimension table
• A Pivot table or chart is usually based around a single fact
table
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4. • Database must either be in a Star or Snowflake model.
This often means de-normalizing some tables or
‘flattening’ the data model. Essentially you need a central
‘fact’ table from which all supporting dimension data
radiates.
• You must flatten many-to-many relationships into a single
table with only the data that you need.
• Based on date data in your central fact table, build a date
dimension table with the columns needed.
• Create a script to populate the date dimension table with
data.
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6. -- Build the Patient_Vaccinations Table
-- This will create a table of 3,462,140 rows
SELECT
PV.VisitID, PV.CountyID, PV.VisitDate, PV.RaceID,
PV.LeadScreening, PV.PatientAge, PV.TargetedCaseMg
mt,
PV.THStepsMed, V.Vaccination, V.VCost
INTO Patient_Vaccinations
FROM PatientVisits PV
JOIN Visits_Vaccinations VV ON PV.VisitID =
VV.VisitID
JOIN Vaccinations Orlando Code Camp 2012
6/16/2012
V ON VV.VaccinationID = 6
V.VaccinationID

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8. • You need to calculate the date range needed for your date dimension.
I usually look for the earliest and latest dates in the fact table and
round the dates to January 1st for the earliest date and December 31st
for the latest date.
• DECLARE @Min_Date DATE;
• DECLARE @Max_Date DATE;
• -- Get the smallest and largest date for start and end of date table
• SET @Min_Date = (SELECT
CONVERT(DATE,'01/01/'+STR(YEAR(MIN(VisitDate)))) FROM
dbo.PatientVisits);
• SET @Max_Date = (SELECT
CONVERT(DATE,'12/31/'+STR(YEAR(MAX(VisitDate)))) FROM
dbo.PatientVisits);
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9. • DECLARE @SQLSTR varchar(8000);
• --Delete Date Dimension table if it exists
• SET @SQLSTR = 'IF OBJECT_ID(''' + @tblname + ''', ''U'') IS NOT NULL
• DROP TABLE ' + @tblname
• EXECUTE(@SQLSTR)
• --Create Date Dimension table
• SET @SQLSTR = 'CREATE TABLE ' + @tblname +
• ' ([PK_Date] [datetime] NOT NULL,
• [Date_Name] [nvarchar](50) NULL,
• [Year] [char](4) NULL,
• [Calendar_Year] [char](13) NULL,
• [Quarter_Of_Year] [char](1) NULL,
• [Quarter_Of_Year_Name] [char](9) NULL,
• [Year_Qtr] [char](6) NULL,
• [Year_Qtr_Name] [char](15) NULL,
• [Month] [char](2) NULL,
• [Month_Name] [char](15) NULL,
• [Year_Month] [char](10) NULL,
• [Year_Month_Name] [char](20) NULL,
• [Day_Of_Year] [char](3) NULL,
• [Day_Of_Year_Name] [char](8) NULL,
• [Day_Of_Month] [int] NULL,
• [Week_Of_Year] [char](2) NULL,
• [Week_Of_Year_Name] [char](7) NULL,
• CONSTRAINT [PK_Time] PRIMARY KEY CLUSTERED
• (
• [PK_Date] ASC
• )WITH (PAD_INDEX = OFF,
• STATISTICS_NORECOMPUTE = OFF,
• IGNORE_DUP_KEY = OFF,
• ALLOW_ROW_LOCKS = ON,
• ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
• ) ON [PRIMARY]'
• EXEC(@SQLSTR)
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10. SET @Loop_Date = @Min_Date;
WHILE @Loop_Date <= @Max_Date
BEGIN
SET @SQLSTR = 'INSERT INTO ' + @tblname + ' VALUES ('''
SET @SQLSTR = @SQLSTR + CAST(@Loop_Date as varchar(30)) + ''', '''
SET @SQLSTR = @SQLSTR + DateName(dw,@Loop_Date) + ', ' + DateName(m,@Loop_Date) + ' ' + RTRIM('0'+CAST(DatePart(d,@Loop_Date) AS char(2)))
+ ' ' + CAST(DatePart(yyyy,@Loop_Date) as char(4)) + ''', '''
SET @SQLSTR = @SQLSTR + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + ''', '''
SET @SQLSTR = @SQLSTR + 'Calendar ' + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + ''', ''‘
SET @SQLSTR = @SQLSTR + CAST(DATEPART(q,@Loop_Date) as CHAR(1)) + ''', '''
SET @SQLSTR = @SQLSTR + 'Quarter ' + CAST(DATEPART(q,@Loop_Date) AS CHAR(1)) + ''', '''
SET @SQLSTR = @SQLSTR + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + '-' + CAST(DATEPART(q,@Loop_Date) AS CHAR(1)) + ''', '''
SET @SQLSTR = @SQLSTR + 'Quarter ' + CAST(DATEPART(q,@Loop_Date) AS CHAR(1)) + ', ' + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + ''', '''
SET @SQLSTR = @SQLSTR + RIGHT('0'+RTRIM(CAST(DATEPART(m,@Loop_Date) As char(2))),2) + ''', '''
SET @SQLSTR = @SQLSTR + DATENAME(m,@Loop_Date) + ''', '''
SET @SQLSTR = @SQLSTR + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + '-' + RIGHT('0'+RTRIM(CAST(DATEPART(m,@Loop_Date) As
char(2))),2) + '-01' + ''', '''
SET @SQLSTR = @SQLSTR + DATENAME(m,@Loop_Date) + ' ' + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + ''', '''
SET @SQLSTR = @SQLSTR + RIGHT('00'+RTRIM(CAST(DATEPART(DayOfYear,@Loop_Date) AS char(3))),3) + ''', '''
SET @SQLSTR = @SQLSTR + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + '-' + RIGHT('00'+RTRIM(CAST(DATEPART(DayOfYear,@Loop_Date)
AS char(3))),3) + ''', '''
SET @SQLSTR = @SQLSTR + RIGHT('0'+RTRIM(CAST(DATEPART(dd,@Loop_Date) AS CHAR(2))),2) + ''', '''
SET @SQLSTR = @SQLSTR + RIGHT('0'+RTRIM(CAST(DATEPART(wk,@Loop_Date) AS char(2))),2) + ''', '''
SET @SQLSTR = @SQLSTR + CAST(DATEPART(yyyy,@Loop_Date) AS CHAR(4)) + '-' + RIGHT('0'+RTRIM(CAST(DATEPART(Wk,@Loop_Date) AS
char(2))),2) + ''')‘
EXECUTE(@SQLSTR)
--Increment loop date and see if at end
SET @Loop_Date = DATEADD(Day,1,@Loop_Date)
END;
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13. • PowerPivot is a data analysis tool
• PowerPivot is a free download from Microsoft
• PowerPivot lets you process millions of rows of data
• PowerPivot uses as much memory as available & multi-cores
• PowerPivot lets you integrate data from multiple sources
• PowerPivot lets you explore, analyze and create analysis
• PowerPivot was originally called: Project ‘Gemini’
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14. • 32-or 64 bit Operating System
• 1 GB of RAM, 2 GB recommended (or more)
• Windows XP with SP3, Vista with SP1, Windows 7
• .NET Framework 3.5 SP1 or better
• Microsoft Office 2010
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15. • Fewer data requests since staff can slice and dice
their own data
• More control over data other people can access
• Users can generate their own reports
• PowerPivot gives SQL Server data access to the
masses
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16. • Use 1 and only 1 header row
• All data in column should be consistently
formatted
• No blank columns
• No blank rows
• Data columns must be 100% filled with data
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17. • Always load the main transaction table first
• This forces the fields to appear at the top of the PowerPivot Field
List.
• PowerPivot’s relationship detection expects the main table to be
first.
• Import lookup tables in their hierarchical order
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18. • Simple Calculations
• Calculated columns within table
• Calculated columns between tables
• Calculated columns to serve as links to other tables
• Calculated columns are calculated for every row in the table.
• Aggregate Calculations
• Calculate unique measures
• Aggregate measures are only calculated for the displayed data in
the Pivot table
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19. • Comprised of 135 functions
• 71 functions are similar to Excel functions
• 69 have the same name – 2 do not
• TEXT  FORMAT
• DATEDIF  YEARFRAC
• 64 functions are unique to DAX
• Aggregate data functions
• Date related functions
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20. • =DATE(<year>, <month>, <day>)
• =DATEVALUE(<date_text>)
• =DAY(<date>)
• =EDATE(<start_date>, <months>)
• =EOMONTH(<start_date>, <months>)
• =HOUR(<datetime>)
• =MINUTE(<datetime>)
• =MONTH(<datetime>)
• =NOW()
• =SECOND(<datetime>)
• =TIME(<hour>, <minute>, <second>)
• =TIMEVALUE(<time_text>)
• =TODAY()
• =WEEKDAY(<datetime>)
• =WEEKNUM(<date>, <return_type>)
• =YEAR(<date>)
• =YEARFRAC(<start_date>, <end_date>, <basis>)
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21. • Get the Year:
=YEAR(Patient_Vaccinations[VisitDate])
• Get Month Number:
=FORMAT(MONTH(Patient_Vaccinations[VisitDate]),"00"
)
• Get name of the month
=FORMAT(Patient_Vaccinations[VisitDate],"MMM")
• Get name of the week day
=FORMAT(WEEKDAY(Patient_Vaccinations[VisitDate]),
"dddd")
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22. • Calculating Quarter of Year
=INT((MONTH(Patient_Vaccinations[VisitDate])-
1)/3)+1
• Calculating Quarter of Year Name
="Qtr " &
INT((MONTH(Patient_Vaccinations[VisitDate])-
1)/3)+1
• Get week number of year
=WEEKNUM(Patient_Vaccinations[VisitDate])
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24. • Download PowerPivot at
• http://www.powerpivot.com/download.aspx
• PowerPivot Sample Data
• http://powerpivotsampledata.codeplex.com
• PowerPivot Tutorial Data
• http://technet.microsoft.com/en-us/library/ee835510.aspx
• DAX On-line Function Reference
• http://technet.microsoft.com/en-us/library/ff452127.aspx
• http://social.technet.microsoft.com/wiki/contents/articles/powerpivot
-dax-text-functions.aspx
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26. Don’t forget to fill out your
evaluations.
Mike@micmin.org
SharePoint Book Site:
http://sharepointmike.wordpress.com/
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