ThoughtWorks Most Frequently Asked Latest SSIS Interview Questions Answers
Perform a conditional update & insert
Components Required: Data Flow Task, Conditional Split, Lookup Transform or Merge Join, OLE DB Command Transform
Use the lookup Transform or Merge Join to detemine if the row exists on the destination and ignore a failed match. If the row yields blank
on the key, then you know the row should be inserted into the target (by Conditional Split). Otherwise, the row is a duplicate or an update. Determine if the row
is an update by comparing the source value to the target value in the Conditional Split. The update can be done by an OLE DB Command Transform or by loading the data
into a staging table.
Perform an incremental load of data
Tasks Required: 2 Execute SQL Tasks, Data Flow Task
Have the 1st Execute SQL Task retrieve a date from a control table of when the target table was last loaded and place that into a variable.
In the Data Flow Task, create a date range on your query using the variable. Then, update the control table using a 2nd Execute SQL Task to specify when the table was
last updated.
What is data flow task in SSIS?
Data flow task is the pumping mechanism that moves data from source to destination. However, in the case of SSIS, you have much more control of what happens from start to finish. In fact, you have a set of out of the box transformation components that you snap together to clean and manipulate the data while it is in the data pipeline.
Just as the control flow handles the main workflow of the package, the Data Flow handles the transformation of data. Almost anything that manipulates data falls into the Data Flow Category.
What is data Profiling task?
Data profiling is the process of analyzing the source data to better understand what condition the data is in, in terms of cleanliness, patterns, numbers or nulls, and so on. data profiling task usually be used at the beginning of the development cycle to support the design of the destination database schema. Note that this task is not used when you develop the normal recurring ETL packages.
What is the multicast Transformation in SSIS?
The Multicast transform, as the name implies, can send single data input to multiple output paths easily. You may want to use this transformation to send a path to multiple destinations sliced in different ways. The multicast transformation is similar to the Split Transformation because both send data to multiple outputs. However, you can not specify the conditions for which part of the data will be in which output in the Multicast transformation.
Move and rename the file at the same time
Tasks Required:
File System Task
Set the File System task to rename the file and point to the directory you’d like to move the file to. This enables you to rename and move the file in the same step.
Loop over an array of data in a table & perform a set of tasks for each row
Tasks Required: Execute SQL Task, Foreach Loop
Use an Execute SQL Task to load the array and send the data into an object variable. Loop over the variable in a Foreach Loop by use an ADO Enumerator.
Difference between Merge and Union All?
The Merge transformation can merge data from two paths into a single output. The Transform is usefull when you wish to break out your Data Flow into a path that handles certain errors and then merge it back into the main Data Flow downstream after the errors have been handled. it’s also useful if you wish to merge data from two Data Sources.
Note that the data must be sorted before using the Merge Transformation. you can do this by using the sort transformation prior to the merge or by specifying an ORDER By clause in the source connection. Also, the metadata must be the same for both paths. For example, CustomerID column cannot be a numeric column in one path and a character column in the other path.
The Union All Transformation works much the same way as the Merge Transformation, but it does not require the data to be sorted. It takes the outputs from multiple sources or transforms and combines them into a single result set.
OLE DB Command Transform?
The OLE DB Command Transform is a component designed to execute a SQL Statement for each row in an input stream. This task is analogous to an ADO Command Object being created, prepared, and executed for each row of a result set. The input stream provides that data for parameters that can be set into the SQL Statement that is either an In – line statement or a stored procedure call.
Execute package task?
The Execute Package Task enables you to build SSIS solutions called parent packages that execute other packages called “Child Packages”. You’ll find this capability an indispensable part of your SSIS development as your packages begin to grow.
Separating packages into discrete functional workflows makes for shorter development and testing cycles and facilitates best development practices. in SSIS, the child package is aware of the parent package parameters and can reach out and access those parameters – level configuration values. The majority of the configurable properties are in the Package tab of the Executable package Task Editor.
The first option is to provide the location of the child package. The options here are either File system and SQL Server. You can deploy SSIS package in the FIle system task as an .dtsx file, or within the msdb database of a SQL Server instance. if you select file system, you must first create a new connection manager connection to the child package.
If the child package is located in a SQL Server, you’ll need to provide the OLE DB Connection Manager for the SQL Server that holds your packages. In either case, browse to and then select the child package within the connection to set the package to execute in the task.
What is Manifest file in SSIS?
Manifiest file is the utility which can be used to deploy the package using wizard on file system and SQL Server database.
Perform a conditional update & insert
Components Required: Data Flow Task, Conditional Split, Lookup Transform or Merge Join, OLE DB Command Transform
Use the lookup Transform or Merge Join to detemine if the row exists on the destination and ignore a failed match. If the row yields blank
on the key, then you know the row should be inserted into the target (by Conditional Split). Otherwise, the row is a duplicate or an update. Determine if the row
is an update by comparing the source value to the target value in the Conditional Split. The update can be done by an OLE DB Command Transform or by loading the data
into a staging table.
Perform an incremental load of data
Tasks Required: 2 Execute SQL Tasks, Data Flow Task
Have the 1st Execute SQL Task retrieve a date from a control table of when the target table was last loaded and place that into a variable.
In the Data Flow Task, create a date range on your query using the variable. Then, update the control table using a 2nd Execute SQL Task to specify when the table was
last updated.
Data flow task is the pumping mechanism that moves data from source to destination. However, in the case of SSIS, you have much more control of what happens from start to finish. In fact, you have a set of out of the box transformation components that you snap together to clean and manipulate the data while it is in the data pipeline.
Just as the control flow handles the main workflow of the package, the Data Flow handles the transformation of data. Almost anything that manipulates data falls into the Data Flow Category.
 |
| ThoughtWorks Most Frequently Asked Latest SSIS Interview Questions Answers |
What is data Profiling task?
Data profiling is the process of analyzing the source data to better understand what condition the data is in, in terms of cleanliness, patterns, numbers or nulls, and so on. data profiling task usually be used at the beginning of the development cycle to support the design of the destination database schema. Note that this task is not used when you develop the normal recurring ETL packages.
What is the multicast Transformation in SSIS?
The Multicast transform, as the name implies, can send single data input to multiple output paths easily. You may want to use this transformation to send a path to multiple destinations sliced in different ways. The multicast transformation is similar to the Split Transformation because both send data to multiple outputs. However, you can not specify the conditions for which part of the data will be in which output in the Multicast transformation.
Move and rename the file at the same time
Tasks Required:
File System Task
Set the File System task to rename the file and point to the directory you’d like to move the file to. This enables you to rename and move the file in the same step.
Loop over an array of data in a table & perform a set of tasks for each row
Tasks Required: Execute SQL Task, Foreach Loop
Use an Execute SQL Task to load the array and send the data into an object variable. Loop over the variable in a Foreach Loop by use an ADO Enumerator.
Difference between Merge and Union All?
The Merge transformation can merge data from two paths into a single output. The Transform is usefull when you wish to break out your Data Flow into a path that handles certain errors and then merge it back into the main Data Flow downstream after the errors have been handled. it’s also useful if you wish to merge data from two Data Sources.
Note that the data must be sorted before using the Merge Transformation. you can do this by using the sort transformation prior to the merge or by specifying an ORDER By clause in the source connection. Also, the metadata must be the same for both paths. For example, CustomerID column cannot be a numeric column in one path and a character column in the other path.
The Union All Transformation works much the same way as the Merge Transformation, but it does not require the data to be sorted. It takes the outputs from multiple sources or transforms and combines them into a single result set.
OLE DB Command Transform?
The OLE DB Command Transform is a component designed to execute a SQL Statement for each row in an input stream. This task is analogous to an ADO Command Object being created, prepared, and executed for each row of a result set. The input stream provides that data for parameters that can be set into the SQL Statement that is either an In – line statement or a stored procedure call.
Execute package task?
The Execute Package Task enables you to build SSIS solutions called parent packages that execute other packages called “Child Packages”. You’ll find this capability an indispensable part of your SSIS development as your packages begin to grow.
Separating packages into discrete functional workflows makes for shorter development and testing cycles and facilitates best development practices. in SSIS, the child package is aware of the parent package parameters and can reach out and access those parameters – level configuration values. The majority of the configurable properties are in the Package tab of the Executable package Task Editor.
The first option is to provide the location of the child package. The options here are either File system and SQL Server. You can deploy SSIS package in the FIle system task as an .dtsx file, or within the msdb database of a SQL Server instance. if you select file system, you must first create a new connection manager connection to the child package.
If the child package is located in a SQL Server, you’ll need to provide the OLE DB Connection Manager for the SQL Server that holds your packages. In either case, browse to and then select the child package within the connection to set the package to execute in the task.
What is Manifest file in SSIS?
Manifiest file is the utility which can be used to deploy the package using wizard on file system and SQL Server database.
Post a Comment