20 SSAS Tabular Interview Questions and Answers

During a technical interview, you may encounter some questions about SSAS Tabular. This business application helps organizations manage its enterprise resource planning, customer relationship management and supply chain processes. Reviewing common questions ahead of time can help you prepare your responses and feel confident on the day of your interview. In this article, we review some questions you may have during your job interview.

SSAS Tabular Interview Questions and Answers

Here are 20 commonly asked SSAS Tabular interview questions and answers to prepare you for your interview:

1. What is SSAS?

SSAS is short for SQL Server Analysis Services, and it is a tool that allows for the creation of OLAP (online analytical processing) cubes. These cubes can be used to provide quick and easy access to data for reporting and analysis purposes.

2. What are the main components of an SSAS solution?

The main components of an SSAS solution are the data source, the data source view, the dimensions, the cubes, and the roles. The data source is where the data for the solution will be coming from, and the data source view is used to define how that data will be accessed and used. The dimensions are used to organize the data, and the cubes are used to store the data. The roles are used to control access to the data.

3. How do you create a cube in SSAS?

The first step is to create a data source view. This will allow you to select the tables and views from the data source that you want to include in your cube. Next, you will create dimensions, which are the structures that will be used to organize the data in the cube. Finally, you will create measures, which are the numeric values that will be used in the cube.

4. Can you explain what OLAP and MOLAP mean in context with SSAS?

OLAP stands for online analytical processing, and it is a type of database that is optimized for data analysis and reporting. MOLAP stands for multidimensional online analytical processing, and it is a type of OLAP database that stores data in a multidimensional structure. SSAS is a server-based software that allows you to create and manage OLAP and MOLAP databases.

5. What do you understand about data sources, data source views, and cubes?

A data source is the location of the data that will be used in the analysis, such as a SQL Server database. A data source view is a logical representation of the data source that includes only the tables and columns needed for the analysis. A cube is a multidimensional data structure that contains measures and dimensions, which are used to analyze the data.

6. When should you use one measure group over another in SSAS?

The answer to this question depends on a few factors, including the size of your data set, the complexity of your measures, and the performance requirements of your application. In general, though, you should use a measure group when you have a large data set that needs to be aggregated in multiple ways, or when you have measures that are complex or need to be highly optimized for performance.

7. What is the purpose of using “partitions” in SSAS?

The purpose of partitions in SSAS is to improve query performance by allowing the query processor to access only the data that is relevant to the current query. Partitions also make it possible to process data incrementally, which can be useful when working with large data sets.

8. Why is it necessary to pre-aggregate data when designing ETL jobs for SSAS?

When you are working with data in SSAS, it is important to remember that the data will be aggregated in order to be displayed in the final report or visualization. This means that if your data is not aggregated properly beforehand, it could lead to inaccurate results. Pre-aggregating data ensures that the data is properly aggregated from the start, which leads to more accurate results in the end.

9. What is your understanding of hierarchies, dimensions, and measures in SSAS?

A hierarchy is a way of organizing data in a logical fashion, often in a tree-like structure. A dimension is a way of categorizing data, and a measure is a value that can be aggregated.

10. How can you define a time dimension, and how does it differ from other dimensions?

A time dimension is a type of dimension that is used to track time data in a data warehouse. Time dimensions are typically used to track historical data, such as sales data over time. Time dimensions can be used to track data at different granularities, such as by year, by quarter, by month, by day, or by hour.

11. What are some typical ways that people use an SSAS model?

People use an SSAS model for a variety of reasons. Some people use it to simply explore data and look for trends. Others use it to generate reports or create dashboards. Still others use it to perform complex analysis, such as predictive modeling or data mining.

12. Can you give me an example of a real-world business scenario where an SSAS model might be used?

A common business scenario where an SSAS model might be used is in data warehousing. In this scenario, data from multiple sources is gathered and stored in a central location (usually a data warehouse) so that it can be analyzed. The SSAS model can be used to help analyze this data and provide insights that can help improve business operations.

13. What types of relationships are supported by SSAS?

There are three types of relationships supported by SSAS: one-to-one, one-to-many, and many-to-many. One-to-one relationships are the most straightforward, and simply mean that each row in one table is linked to one row in another table. One-to-many relationships are a bit more complex, and mean that each row in the first table can be linked to multiple rows in the second table. Many-to-many relationships are the most complex, and mean that each row in the first table can be linked to multiple rows in the second table, and vice versa.

14. Can you explain what drillthrough actions are in SSAS?

Drillthrough actions are a type of action that can be defined in SSAS Tabular that allows the user to click on a value in a report and be taken to a new report that contains more detailed information about that value.

15. What are the differences between JIT compilation and AOT compilation?

AOT compilation is a process that compiles the entire SSAS Tabular model at once, while JIT compilation only compiles the parts of the model that are needed at runtime. JIT compilation is generally faster and more efficient, but AOT compilation can be helpful in some cases where the entire model needs to be compiled ahead of time.

16. How do you configure permissions on an SSAS database or cube?

You can configure permissions on an SSAS database or cube by using role-based security. You can create roles and then assign users or groups to those roles. The roles will determine what level of access the users or groups will have to the database or cube.

17. Are there any known limitations with SSAS? If yes, then what do you know about them?

Yes, there are some known limitations with SSAS. One such limitation is that it does not support all data types that are available in SQL Server. Additionally, it can be difficult to work with large data sets due to the amount of memory required.

18. What’s the difference between a role and a user in SSAS?

A role is a collection of users who all have the same permissions. A user is a single person who has access to a SSAS database.

19. What are some common errors that you may encounter while working with SSAS?

Some common errors that you may encounter while working with SSAS include:

• “The connection either timed out or was lost” – This error can occur if the connection to the data source is lost or if the query is taking too long to execute.

• “A connection cannot be made. Ensure that the server is running” – This error can occur if the connection to the data source is lost or if the data source is unavailable.

• “The operation has been cancelled” – This error can occur if the query is taking too long to execute or if the user cancels the operation.

20. What is the best way to build an efficient SSAS cube?

The best way to build an efficient SSAS cube is to use a star schema. A star schema is a type of database schema that is designed to optimize query performance by organizing data into a series of dimensions and fact tables. By using a star schema, you can minimize the number of joins that are required to retrieve data, which can greatly improve query performance.