SQL Server Query Fundamentals: A Simple example of a Query that uses PIVOT:

Problem:

Convert the following source data into a schema shown below:

SQL SERVER TSQL PIVOTSolution:

Here’s the code that uses PIVOT function to get to the solution, please use this as a starting point.

Note the use of aggregation function avg – this will depend on the requirement. In the example, the Test_value need to be average if more than one tests were performed.


-- source data
SELECT [Product_ID],[Test_Desc],[Test_Val] FROM [dbo].[Address]
go

-- Destination data using PIVOT function
select * from [dbo].[Address]
pivot( avg(test_val) for test_Desc IN (Test1,Test2,Test3,Test4,Test5)) 
as Tests

SSIS: Using Data Profiling Task to check the candidate key profile of unknown data source(s)

As a part of Business Intelligence projects, we spend a significant amount in extracting, transforming and loading data from source systems. So it’s always helpful to know as much as you can about the data sources like NULLS, keys, statistics among other things. One of the things that I like to do if the data is unknown is to make sure that I get the candidate keys correct to make sure the key used can uniquely identify the rows in the data. It’s really helpful if you do this upfront because it would avoid a lot of duplicate value errors in your projects.

So here’s a quick tutorial on how you can check the candidate key profile using data profiling task in SSIS, You need to perform two main tasks:
1. Generate the xml file using the Data profiling task in SSIS
2. View the content of the xml file using the Data Profile Viewer Tool or using the Open Profile Viewer option in the Data Profiling task editor in SSIS.

Here are the steps:
1a. Open SQL Server Data Tools (Visual Studio/BIDS) and the SSIS project type
1b. Bring in Data Profiling Task on Control Flow
1c. Open the Data Profiler Task editor and configure the destination folder that the tasks uses to create the XML file. You can either create a new connection or use an existing one. If you use an existing connection, make sure that you are setting the OverwriteDestination property to True if you want the file to be overwritten at the destination.

1 SSIS Data Profiling Task Data Cleaning Candidate Key

1d. Click on Quick Profile to configure the data source for the data profiler task

2 SSIS Data Profiling Task Data Cleaning Candidate Key

1e. In the quick profile form, you’ll need to select the connection, table/view and also specify what you to need to computer. For candidate key profile, make sure that the candidate key profile box is checked.

3 SSIS Data Profiling Task Data Cleaning Candidate Key

1f. Run the Task and a XML file should be placed at the destination you specified in step 1C.

Now, It’s time to view what profiler captured.

2a. you can open “Data Profile Viewer” by searching for its name in the start button.

4 SSIS Data Profiling Task Data Cleaning Candidate Key

2b. once it opens up, click on open and browse to the xml file generated by the data profiling task.

5 SSIS Data Profiling Task Data Cleaning Candidate Key

2c. once the file opens up, you can the candidate key profiles.

6 SSIS Data Profiling Task Data Cleaning Candidate Key

2d. Alternatively, You can also open the data profile viewer from the “Data Profiling Task” in SSIS. Go to the Editor > Open Profile Viewer:

7 SSIS Data Profiling Task Data Cleaning Candidate Key

Conclusion:
In this post, you saw how to profile data using the Data Profiling Task in SSIS.

TSQL – Quick note about numeric data type to solve “Arithmetic overflow error”

Problem:

You are working on a query where you are trying to convert source data to numeric data type and you get an “Arithmetic overflow error”.

Solution:

Let’s understand this with an example:

Here’s the source data: 132.56000000 and you want to store just 132.56 so write a query that looks like:

cast( as numeric(3,2)) as destination_column_name

and after you run the query its throws an error “Arithmetic Overflow Error” – so what’s wrong?

The issue is that you incorrectly specified the precision and scale – by writing the query that says numeric(3,2) you are saying I want 3 data places with 2 on the right (after decimal point) which leaves just 1 place for left.

what you need to write is numeric(5,2) – and this will have 2 places on the right and leaves 3 places for left.

so after you run this, it shouldn’t complain about the arithmetic overflow error. you just need to make sure that the precision and scale of the numeric data type is correct.

Conclusion:

In this post, you saw an example of how to correctly use the precision and scale in the numeric data type and that should help you solve the arithmetic overflow errors.

SSIS – How to use Execute SQL Task to assign value to a variable?

Problem:

How to use Execute SQL Task in SSIS to assign value to a variable?

Solution:

This is a beginner level post so I’ll show you how you can use Execute SQL Task to assign a value to a variable. Note that variables can also be given full result set. With that said, here are the steps:

1. Create the query against the source system

Example: ((Note the column name, this will be handy later!)

1 Execute SQL Task SSIS Query

2. Open SSIS Project > Create the variable

Example

Variable SSIS Create Steps3. Now, drag a Execute SQL Task to Control Flow. Rename it. And go to Edit. Configure SQL Statement Section

Execute SQL Statement SSIS4. Now, since we want to store a value to the variable, change the Result Set property to Single Row

Single ROW SQL Statement Server SSIS5. One last step, go to result set section and map Result Name (remember the column name from #1?!) with Variable Name:

Result Set SSIS Execute SQL TaskThat’s it! Related article: How to see value of variable during Run Time?

Conclusion:

In this post, you saw how to use Execute SQL Task in SQL server integration services to assign a value to a variable.

SQL Server Analysis services – How to set the order by attribute sort key?

Problem:

How to sort the dimension attribute by something other than the key and name column? How do you set the “OrderBy” property?

Example: You have created an Inventory age buckets 1-50,51-100,101-150 and so if a business user uses this dimension attribute then the sorting won’t be logical. It would be 1-50, 101-150,51-100 – so how to show the buckets in the logical order?

Solution:

1. make sure that the table/view that you are bringing in has the sort key.

Example:

1 SSAS Attribute order by sort key2. Now, switch to SSAS and open your dimension. I am assuming that you’ve already configured your data source views and you are already bringing in these columns in the dimension:

Dim Inventory SSAS SSIS VIEW Data source VIEW

3. Let’s start with hiding Aging Bucket Sort key so that it’s not visible to user. Change the AttributeHierarchyVisible to False

4. Now, switch to Attribute Relationships – Right Click on Aging Bucket and click on New Attribute Relationship. And set the attribute relanship between Aging bucket and Aging Bucket Sort Key

Attribute Relationships SSAS

And you should see something like this in your attribute relationship section:

SSAS Attribute Relationship Sort Key

5. Now, one more thing to configure. Go back to dimension structure section. Open the properties section for the Aging Bucket Attribute and change the OrderBy property to AttributeKey. Also, change the orderByAttribute property to Aging Bucket Sort Key (in your case, choose the sort key that you have)

SSAS Order Sort by attribute property

That’s it, after you process the model then you should see the attribute being sorted based on the sort key that you had.

Conclusion:

In this post, you saw how to configure sort/order property of a dimension attribute.

Design pattern for making staging table loads incremental in SSIS:

Summary:

This is a beginner level post targeted at Developers who are new to SSIS and may not have worked on making a SSIS staging load package incremental. In this post, I’ll share a design pattern that I’ve used to make staging loads incremental which pulls in just new or changed rows from source system.

Tutorial:

Before we begin, why would you want to make a staging load incremental when pulling data from source systems? Two main reasons: 1) the source system may not keep historical data but your Business Intelligence system needs to have it 2) it is also faster and puts less strain on source system while doing data pull.

since this is a beginner’s level, I am going to show you a design pattern when you have a column in the source system that can identify New or Changed Rows. If you do not have a column in the source system that identifies new or changed rows then this topic becomes an advanced level and is out of scope for now.

with that said, let’s see the steps involved.

1) I’ve this kill and fill (a.k.a Full Load) package in my SSIS dev environment:

1 Full Load Source Table Destination SSIS2) now, let’s make this incremental. so I’ll go ahead and delete the Execute SQL Task that truncates the data.

3) Now, we need a way to be able to pass in the query in our DFT that gets only the new or changed rows. The source system that I am using has a field called modified date and that’s what I’ll be using to pull in new or changed data.

4) Let’s create the query using the help of variables, execute sql task and script task. (Later, we’ll store in the query in a variable and use that variable in the Data Flow Task)

4a) create ModfiedDate and Query variables

4b) create an Execute SQL Task to run the query to get the max ModifiedDate and write it in the ModifiedDate variable that you created.

Related Post: How to use Execute SQL Task to assign value to a variable?

4c) create a Script Task to get the query using the ModifiedDate variable. This query will extract only new or changed rows from your source system


Dim ModifiedDate As String
Dim sQuery As String
ModifiedDate = Dts.Variables("ModifiedDate").Value.ToString
sQuery = String.Concat("SELECT [SalesOrderID],[SalesOrderDetailID],[CarrierTrackingNumber],[OrderQty],[ProductID],[SpecialOfferID],[UnitPrice],[ModifiedDate] FROM [sales].[SalesOrderDetail] where [ModifiedDate] >= '", String.Concat(ModifiedDate, "'"))
MsgBox(String.Concat("   ", sQuery))
Dts.Variables("Query").Value = sQuery

5) Now, go to variables section and give a default value to user::Query variable because if you do not do this you won’t be able to go to next steps.

6) Go to Data Flow and change the OLEDB source to use the SQL Command from variable and use the user::Query variable

7) Switch to Control flow and Make sure your precedence constraints are set to run Execute SQL Task > Script Task > Data Flow Task

8) Run the package and you should see the dynamic query that gets generated.
Tip: sometimes it’s helpful to run this query that’s generated against the source system for troubleshooting purpose.

SSIS Incremental Load Staging Table

9) On the successful run of the package verify that only new rows got added to the staging table. Also, if there are duplicate rows in the staging table, this might need to handled during the dimension load or fact load. you can also consider having the logic in place here to avoid duplicate records in your staging table.

That’s it!

SSIS Incremental Load Staging Table 2

Conclusion:

In this post, you saw how to make a staging load package incremental.

Similar Blog:

SQL Server Integration services: How to write a package that does Set based updates?

SQL server Integration services: How to solve “The value violated the integrity constraints for the column” error?

problem:

you are working on an SSIS package to load a table from a source system and you get an error “The value violated the integrity constraints for the column error” – how do you solve it?

solution:

one the things that the error message should also tell you would be column name. What you want to do is check the table definition of the destination table for any integrity constraints like NOT NULL or PRIMARY KEY. Now once you have that information, go back to your source and figure out if it’s trying to add NULL values in a column that has NOT NULL integrity constraint. Or may be ETL logic is trying to insert duplicate value to the column that has primary key constraint.

Also, the don’t alter the destination table to accept NULL’s or remove integrity constraint. You want to put a logic in your ETL OR fix the data integrity at source. You can use TSQL functions like NULLIF to handle NULL values while querying source systems.

Conclusion:
In this post, we saw how to solve the “The value violated the integrity constraints for the column” error in SSIS.

SQL Server Integration services: How to write a package that does Set based updates?

Problem:

if you’ve a sizable number of rows that need update in SSIS, then you don’t want to do a row based update commands because it won’t be efficient. if you’ve good number of rows that need to be updated then you can use the SET Based updates. it’s a common design pattern for loading dimensions in a data warehouse.

Find the steps below:

Solution:

There are two main steps to achieve this:

1) Populate the “update” table with rows that have been changed. Note that a new table needs to be created.

2) Run the SQL command to do a SET based update

1. SSIS Set based Updates Integration ServicesLet’s see each step in detail:

1)  Populate the “update” table with rows that have changed.

For this step, first make sure that you have a table that can hold the rows that have been updated.

Then create a Data Flow that take the source data and lookups the data that has changed and puts it in an update/staging table:

2 SSIS Populate the Table with Rows that changed

Note: I’ve used a small table for demo purpose but you won’t use this method if you don’t have a more rows to update because as you can see this method adds an overhead of putting the data in the update table first.

2) Run the SQL command to do a SET based update

Here’s the sample query:

-- run the update command
Update Dim
Set
    [Column1]=Upd.[Column1]
    [Column2]=Upd.[Column2]
--  [Column3]=Upd.[Column3]	
--  ... 
From dbo.DimDestination Dim
Inner Join dbo.Destination_update Upd
on Dim.Destination_sk=Upd.Destination_sk
  
--Truncate update table
Truncate table dbo.Destination_update

Conclusion:

In this post, we saw how to write a package in SSIS that does SET based updates.

SQL server Analysis Services: How to import cube meta data to SQL server Data Tools?

Problem:

Someone on your team deployed a cube and gave you access to it. Now, as an IT developer on the team you want to know the calculation that was used for some of the measures. How do get it? You can email the contact person, right? Sure, but let me show you how you can decrease email back and forth using the following steps.

Note: it’s applicable to both multidimensional model as well as tabular model.

Solution:

1. Open SSDT

2. File > Project > New

3. Installed Templates > Business Intelligence > Analysis services > Import from Server

SQL Server Analysis Services Business Intelligence Import

4. You’ll get a dialog box, enter server name and the cube/model metadata that you want to import

Import Microsoft Business Intelligence analysis cube

5. In the solution explorer, you should be able to see the cube meta data! Now, you can go look at the measure calculation that you wanted to see, or may be the KPI rule? or something else in the cube that you needed to know.

Conclusion:

In this post, I described how you can import SQL server analysis services cube/model from the server.

SQL Server reporting services: How to use the Split function in the SSRS expressions to get sub-string?

Problem Statement:
How do you use SQL Server Reporting Services (SSRS) expression to get sub-string from the inputted text?

Solution:
I am going to show you few SSRS expressions that you can use in your SSRS reports:

SSRS SQL Server Reporting Services Expression SPLIT

Here’s the same in a text:

Input: SSRS Expression used: Output:
[Date].[Fiscal Year].&[2008] Split(Parameters!DateFiscalYear.Value,”&”)(1) [2008]
[Date].[Fiscal Year].&[2008] Split(Parameters!DateFiscalYear.Value, “.”)(2) &[2008]
[Date].[Fiscal Year].&[2008] Split(Split(Split(Parameters!DateFiscalYear.Value, “&”)(1),”[")(1),"]“)(0) 2008
[Date].[Fiscal Year].&[2008] Parameters!DateFiscalYear.Value.Split(“&”)(1) [2008]

Conclusion:
In this post, you saw how to use the split function in SQL Server Reporting Services (SSRS) expressions to get a sub-string.