Intuit Most Frequently Asked Latest SSIS Interview Questions Answers
What is the SSIS package and what does it do?
SSIS (SQL Server Integration Services) is an upgrade of DTS (Data Transformation Services), which is a feature of the previous version of SQL Server. SSIS packages can be created in BIDS (Business Intelligence Development Studio). These can be used to merge data from heterogeneous data sources into SQL Server. They can also be used to populate data warehouses, to clean and standardize data, and to automate administrative tasks.
SQL Server Integration Services (SSIS) is a component of Microsoft SQL Server 2005. It replaces Data Transformation Services, which has been a feature of SQL Server since Version 7.0. Unlike DTS, which was included in all versions, SSIS is only available in the “Standard” and “Enterprise” editions.
Integration Services provides a platform to build data integration and workflow applications. The primary use for SSIS is data warehousing as the product features a fast and flexible tool for data extraction, transformation, and loading (ETL).). The tool may also be used to automate maintenance of SQL Server databases, update multidimensional cube data, and perform other functions.
Loop over a list of files & load each one
Tasks Required: Foreach Loop, Data Flow Task
Configure the Foreach Loop to loop over any particular directory of files. The loop should be configured to output
to a given variable. Map the given variable to a connection manager by using expressions.
Difference between Execute TSQL Task and Execute SQL Task
In SSIS there is one tasks Execute TSQL task which is similar to Execute SQL task. Will see what is the difference between two.
Execute TSQL Task:
Pros: Takes less memory, faster perfomance Cons: Output into variable not supported, Only supports ADO.net connection
Execute SQL Task:
Pros: Support output into variables and multiple types of connection, parameterized query possible. Cons: Takes more memory, slower performance compared to TSQL task.
Precedence Constraints?
A task will only execute if the condition that is set by the precedence constraint preceding the task is met. By using these constraints, it will choose different execution paths depending on the success or failure of other tasks.
Success – Workflow will proceed when the preceding containter executes successfully. Indicated in control flow by a solid green line. Failure – Workflow will proceed when the preceding container’s execution results in a failure. Indicated in control flow by a solid red line. Completion – Workflow will proceed when the preceding container’s execution completes, regardless of success or failure. Indicated in control flow by a solid blue line.
Expression/Constraint with logical AND – workflow will proceed when specified expression and constraints evaluate to true. Indicated in control flow by a solid color line along with a small ‘fx’ icon next to it. Color of line depends on logical constraint chosen (e.g. success = green, completion = blue).
What is the use of config file in SSIS?
Config file in SSIS is used to provide inputs to connection manager different properties which package use to assign values at runtime dynamically.
Using config file user need to make changes to the config file which package will take automatically at runtime because of using it you don’t need to every time make changes in the packages in case you are deploying package on multiple servers or locations. There are multiple ways in which configuration values can be stored.
XML configuration file: Store the config file as an XML file..
Environment variable Store the config in on of the environment variables.
Registry entry Store the confi in the registry
Parent package variable Store the config as a variable in the package that contains the tasks.
SQL Server Store the config in t a table in SQL Server
Different between Control Flow and Data Flow?
Control flow is for designing the flow of the package. Data flow is for ETL process. Data Flow is the subset of control flow There will be only one control flow while multiple dataflow can exists. Data flow cannot work without a control flow
All process base taks are part of control flow while ETL related tasks are the part of Dataflow which is again a subset of control flow.
What is Conditional Split transformation in SSIS?
This is just like IF condition which checks for the given condition and based on the condition evaluation, the output will be sent to the appropriate OUTPUT path. It has ONE input and MANY outputs. Conditional Split transformation is used to send paths to different outputs based on some conditions. For example, we can organize the transform for the students in a class who have marks greater than 40 to one path and the students who score less than 40 to another path.
How do you eliminate quotes from being uploaded from a flat file to SQL Server?
This can be done using TEXT QUALIFIER property. In the SSIS package on the Flat File Connection Manager Editor, enter quotes into the Text qualifier field then preview the data to ensure the quotes are not included.
Can you explain how to setup a checkpoint file in SSIS?
The following items need to be configured on the properties tab for SSIS package:
CheckpointFileName – Specify the full path to the Checkpoint file that the package uses to save the value of package variables and log completed tasks. Rather than using a hard-coded path as shown above, it’s a good idea to use an expression that concatenates a path defined in a package variable and the package name.
CheckpointUsage – Determines if/how checkpoints are used. Choose from these options: Never(default), IfExists, or Always. Never indicates that you are not using Checkpoints. IfExists is the typical setting and implements the restart at the point of failure behavior. If a Checkpoint file is found it is used to restore package variable values and restart at the point of failure. If a Checkpoint file is not found the package starts execution with the first task. The Always choice raises an error if the Checkpoint file does not exist.
SaveCheckpoints – Choose from these options: True or False (default). You must select True to implement the Checkpoint behavior.
What are the different values you can set for CheckpointUsage property ?
There are three values, which describe how a checkpoint file is used during package execution:
1) Never: The package will not use a checkpoint file and therefore will never restart.
2) If Exists: If a checkpoint file exists in the place you specified for the CheckpointFilename property, then it will be used, and the package will restart according to the checkpoints written.
3) Always: The package will always use a checkpoint file to restart, and if one does not exist, the package will fail.
What do we mean by dataflow in SSIS?
Data flow is nothing but the flow of data from the corresponding sources to the referred destinations. In this process, the data transformations make changes to the data to make it ready for the data warehouse.
What is a breakpoint in SSIS? How is it setup? How do you disable it?
A breakpoint is a stopping point in the code. The breakpoint can give the Developer\DBA an
opportunity to review the status of the data, variables and the overall status of the SSIS package.
10 unique conditions exist for each breakpoint.
Breakpoints are setup in BIDS. In BIDS, navigate to the control flow interface. Right click on the
object where you want to set the breakpoint and select the ‘Edit Breakpoints…’ option.
Can you name 5 or more of the native SSIS connection managers?
1) OLEDB connection – Used to connect to any data source requiring an OLEDB connection (i.e.,
SQL Server 2000)
2) Flat file connection – Used to make a connection to a single file in the File System. Required for reading information from a File System flat file
3) ADO.Net connection – Uses the .Net Provider to make a connection to SQL Server 2005 or other
connection exposed through managed code (like C#) in a custom task
4) Analysis Services connection – Used to make a connection to an Analysis Services database or project. Required for the Analysis Services DDL Task and Analysis Services Processing Task
5) File connection – Used to reference a file or folder. The options are to either use or create a file or folder
6) Excel
What is the use of Bulk Insert Task in SSIS?
Bulk Insert Task is used to upload large amount of data from flat files into Sql Server. It supports only OLE DB connections for destination database.
What is the ONLY Property you need to set on TASKS in order to configure CHECKPOINTS to RESTART package from failure?
The one property you have to set on the task is FailPackageOnFailure. This must be set for each task or container that you want to be the point for a checkpoint and restart. If you do not set this property to true and the task fails, no file will be written, and the next time you invoke the package, it will start from the beginning again.
Where can we set the CHECKPOINTS, in DataFlow or ControlFlow ?
Checkpoints only happen at the Control Flow; it is not possible to checkpoint transformations or restart inside a Data Flow. The Data Flow Task can be a checkpoint, but it is treated as any other task.
Can you explain different options for dynamic configurations in SSIS?
1) XML file
2) custom variables
3) Database per environment with the variables
4) Use a centralized database with all variables
What is the use of Percentage Sampling transformation in SSIS?
Percentage Sampling transformation is generally used for data mining. This transformation builds a random sample of set of output rows by choosing specified percentage of input rows. For example if the input has 1000 rows and if I specify 10 as percentage sample then the transformation returns 10% of the RANDOM records from the input data.
What are the different types of Data flow components in SSIS?
There are 3 data flow components in SSIS.
1. Sources
2. Transformations
3. Destinations
What are the different types of data sources available in SSIS?
There are 7 types of data sources provided by SSIS: a.) Data Reader source b.) Excel source c.) Flat file source d.) OLEDB source e.) Raw file source f.) XML source g.) Script component
What is SSIS Designer?
It is a graphical tool for creating packages. It has 4 tabs: Control Flow, Data Flow, Event Handlers and Package Explorer.
What is Control Flow tab?
It is the tab in SSIS designer where various Tasks can be arranged and configured. This is the tab where we provide and control the program flow of the project.
What is the SSIS package and what does it do?
SSIS (SQL Server Integration Services) is an upgrade of DTS (Data Transformation Services), which is a feature of the previous version of SQL Server. SSIS packages can be created in BIDS (Business Intelligence Development Studio). These can be used to merge data from heterogeneous data sources into SQL Server. They can also be used to populate data warehouses, to clean and standardize data, and to automate administrative tasks.
SQL Server Integration Services (SSIS) is a component of Microsoft SQL Server 2005. It replaces Data Transformation Services, which has been a feature of SQL Server since Version 7.0. Unlike DTS, which was included in all versions, SSIS is only available in the “Standard” and “Enterprise” editions.
Integration Services provides a platform to build data integration and workflow applications. The primary use for SSIS is data warehousing as the product features a fast and flexible tool for data extraction, transformation, and loading (ETL).). The tool may also be used to automate maintenance of SQL Server databases, update multidimensional cube data, and perform other functions.
Loop over a list of files & load each one
Tasks Required: Foreach Loop, Data Flow Task
Configure the Foreach Loop to loop over any particular directory of files. The loop should be configured to output
to a given variable. Map the given variable to a connection manager by using expressions.
Difference between Execute TSQL Task and Execute SQL Task
In SSIS there is one tasks Execute TSQL task which is similar to Execute SQL task. Will see what is the difference between two.
Execute TSQL Task:
Pros: Takes less memory, faster perfomance Cons: Output into variable not supported, Only supports ADO.net connection
Execute SQL Task:
Pros: Support output into variables and multiple types of connection, parameterized query possible. Cons: Takes more memory, slower performance compared to TSQL task.
 |
| Intuit Most Frequently Asked Latest SSIS Interview Questions Answers |
Precedence Constraints?
A task will only execute if the condition that is set by the precedence constraint preceding the task is met. By using these constraints, it will choose different execution paths depending on the success or failure of other tasks.
Success – Workflow will proceed when the preceding containter executes successfully. Indicated in control flow by a solid green line. Failure – Workflow will proceed when the preceding container’s execution results in a failure. Indicated in control flow by a solid red line. Completion – Workflow will proceed when the preceding container’s execution completes, regardless of success or failure. Indicated in control flow by a solid blue line.
Expression/Constraint with logical AND – workflow will proceed when specified expression and constraints evaluate to true. Indicated in control flow by a solid color line along with a small ‘fx’ icon next to it. Color of line depends on logical constraint chosen (e.g. success = green, completion = blue).
What is the use of config file in SSIS?
Config file in SSIS is used to provide inputs to connection manager different properties which package use to assign values at runtime dynamically.
Using config file user need to make changes to the config file which package will take automatically at runtime because of using it you don’t need to every time make changes in the packages in case you are deploying package on multiple servers or locations. There are multiple ways in which configuration values can be stored.
XML configuration file: Store the config file as an XML file..
Environment variable Store the config in on of the environment variables.
Registry entry Store the confi in the registry
Parent package variable Store the config as a variable in the package that contains the tasks.
SQL Server Store the config in t a table in SQL Server
Different between Control Flow and Data Flow?
Control flow is for designing the flow of the package. Data flow is for ETL process. Data Flow is the subset of control flow There will be only one control flow while multiple dataflow can exists. Data flow cannot work without a control flow
All process base taks are part of control flow while ETL related tasks are the part of Dataflow which is again a subset of control flow.
What is Conditional Split transformation in SSIS?
This is just like IF condition which checks for the given condition and based on the condition evaluation, the output will be sent to the appropriate OUTPUT path. It has ONE input and MANY outputs. Conditional Split transformation is used to send paths to different outputs based on some conditions. For example, we can organize the transform for the students in a class who have marks greater than 40 to one path and the students who score less than 40 to another path.
How do you eliminate quotes from being uploaded from a flat file to SQL Server?
This can be done using TEXT QUALIFIER property. In the SSIS package on the Flat File Connection Manager Editor, enter quotes into the Text qualifier field then preview the data to ensure the quotes are not included.
Can you explain how to setup a checkpoint file in SSIS?
The following items need to be configured on the properties tab for SSIS package:
CheckpointFileName – Specify the full path to the Checkpoint file that the package uses to save the value of package variables and log completed tasks. Rather than using a hard-coded path as shown above, it’s a good idea to use an expression that concatenates a path defined in a package variable and the package name.
CheckpointUsage – Determines if/how checkpoints are used. Choose from these options: Never(default), IfExists, or Always. Never indicates that you are not using Checkpoints. IfExists is the typical setting and implements the restart at the point of failure behavior. If a Checkpoint file is found it is used to restore package variable values and restart at the point of failure. If a Checkpoint file is not found the package starts execution with the first task. The Always choice raises an error if the Checkpoint file does not exist.
SaveCheckpoints – Choose from these options: True or False (default). You must select True to implement the Checkpoint behavior.
What are the different values you can set for CheckpointUsage property ?
There are three values, which describe how a checkpoint file is used during package execution:
1) Never: The package will not use a checkpoint file and therefore will never restart.
2) If Exists: If a checkpoint file exists in the place you specified for the CheckpointFilename property, then it will be used, and the package will restart according to the checkpoints written.
3) Always: The package will always use a checkpoint file to restart, and if one does not exist, the package will fail.
What do we mean by dataflow in SSIS?
Data flow is nothing but the flow of data from the corresponding sources to the referred destinations. In this process, the data transformations make changes to the data to make it ready for the data warehouse.
What is a breakpoint in SSIS? How is it setup? How do you disable it?
A breakpoint is a stopping point in the code. The breakpoint can give the Developer\DBA an
opportunity to review the status of the data, variables and the overall status of the SSIS package.
10 unique conditions exist for each breakpoint.
Breakpoints are setup in BIDS. In BIDS, navigate to the control flow interface. Right click on the
object where you want to set the breakpoint and select the ‘Edit Breakpoints…’ option.
Can you name 5 or more of the native SSIS connection managers?
1) OLEDB connection – Used to connect to any data source requiring an OLEDB connection (i.e.,
SQL Server 2000)
2) Flat file connection – Used to make a connection to a single file in the File System. Required for reading information from a File System flat file
3) ADO.Net connection – Uses the .Net Provider to make a connection to SQL Server 2005 or other
connection exposed through managed code (like C#) in a custom task
4) Analysis Services connection – Used to make a connection to an Analysis Services database or project. Required for the Analysis Services DDL Task and Analysis Services Processing Task
5) File connection – Used to reference a file or folder. The options are to either use or create a file or folder
6) Excel
What is the use of Bulk Insert Task in SSIS?
Bulk Insert Task is used to upload large amount of data from flat files into Sql Server. It supports only OLE DB connections for destination database.
What is the ONLY Property you need to set on TASKS in order to configure CHECKPOINTS to RESTART package from failure?
The one property you have to set on the task is FailPackageOnFailure. This must be set for each task or container that you want to be the point for a checkpoint and restart. If you do not set this property to true and the task fails, no file will be written, and the next time you invoke the package, it will start from the beginning again.
Where can we set the CHECKPOINTS, in DataFlow or ControlFlow ?
Checkpoints only happen at the Control Flow; it is not possible to checkpoint transformations or restart inside a Data Flow. The Data Flow Task can be a checkpoint, but it is treated as any other task.
Can you explain different options for dynamic configurations in SSIS?
1) XML file
2) custom variables
3) Database per environment with the variables
4) Use a centralized database with all variables
What is the use of Percentage Sampling transformation in SSIS?
Percentage Sampling transformation is generally used for data mining. This transformation builds a random sample of set of output rows by choosing specified percentage of input rows. For example if the input has 1000 rows and if I specify 10 as percentage sample then the transformation returns 10% of the RANDOM records from the input data.
What are the different types of Data flow components in SSIS?
There are 3 data flow components in SSIS.
1. Sources
2. Transformations
3. Destinations
What are the different types of data sources available in SSIS?
There are 7 types of data sources provided by SSIS: a.) Data Reader source b.) Excel source c.) Flat file source d.) OLEDB source e.) Raw file source f.) XML source g.) Script component
What is SSIS Designer?
It is a graphical tool for creating packages. It has 4 tabs: Control Flow, Data Flow, Event Handlers and Package Explorer.
What is Control Flow tab?
It is the tab in SSIS designer where various Tasks can be arranged and configured. This is the tab where we provide and control the program flow of the project.
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