SSIS (SQL Server Integration Services) Interview questions Part - 1

SSIS Interview Questions

 

Q: What is SSIS? How it related with SQL Server.
SQL Server Integration Services (SSIS) is a component of SQL Server which can be used to perform a wide range of Data Migration and ETL operations. SSIS is a component in MSBI process of SQL Server.
This is a platform for Integration and Workflow applications. It is known for a fast and flexible OLTP and OLAP extensions used for data extraction, transformation, and loading (ETL). The tool may also be used to automate maintenance of SQL Server databases and multidimensional data sets.

Q: What are the tools associated with SSIS?
We use Business Intelligence Development Studio (BIDS) and SQL Server Management Studio (SSMS) to work with Development of SSIS Projects.
We use SSMS to manage the SSIS Packages and Projects.

Q: What are the differences between DTS and SSIS

Data Transformation Services	SQL Server Integration Services
Limited Error Handling	Complex and powerful Error Handling
Message Boxes in ActiveX Scripts	Message Boxes in .NET Scripting
No Deployment Wizard	Interactive Deployment Wizard
Limited Set of Transformation	Good number of Transformations
NO BI functionality	Complete BI Integration

Q: What is a workflow in SSIS ?
Workflow is a set of instructions on to specify the Program Executor on how to execute tasks and containers within SSIS Packages.
 
Q: What is the control flow?

A control flow consists of one or more tasks and containers that execute when the package runs. To control order or define the conditions for running the next task or container in the package control flow, we use precedence constraints to connect the tasks and containers in a package. A subset of tasks and containers can also be grouped and run repeatedly as a unit within the package control flow. SQL Server 2005 Integration Services (SSIS) provides three different types of control flow elements: Containers that provide structures in packages, Tasks that provide functionality, and Precedence Constraints that connect the executables, containers, and tasks into an ordered control flow.

Q: What is a data flow?
A data flow consists of the sources and destinations that extract and load data, the transformations that modify and extend data, and the paths that link sources, transformations, and destinations The Data Flow task is the executable within the SSIS package that creates, orders, and runs the data flow. A separate instance of the data flow engine is opened for each Data Flow task in a package. Data Sources, Transformations, and Data Destinations are the three important categories in the Data Flow.

Q: How does Error-Handling work in SSIS
When a data flow component applies a transformation to column data, extracts data from sources, or loads data into destinations, errors can occur. Errors frequently occur because of unexpected data values.

Type of typical Errors in SSIS:
-Data Connection Errors, which occur incase the connection manager cannot be initialized with the connection string. This applies to both Data Sources and Data Destinations along with Control Flows that use the Connection Strings.
-Data Transformation Errors, which occur while data is being transformed over a Data Pipeline from Source to Destination.
-Expression Evaluation errors, which occur if expressions that are evaluated at run time perform invalid

Q: What is environment variable in SSIS?
An environment variable configuration sets a package property equal to the value in an environment variable.
Environmental configurations are useful for configuring properties that are dependent on the computer that is executing the package.