General Knowledge Question with Answer

 General Knowledge

Python Question with Solutions

Python Question with Solutions

 1. What is Python? What are the benefits of using Python? 

Ans. Python is a programming language with objects, modules, threads, exceptions and automatic memory management. The benefits of Python are that it is simple and easy, portable, extensible, built-in data structure and is open source. 

2. What is pickling and unpickling? 

Ans. Pickle module accepts any Python object and converts it into a string representation and dumps it into a file by using dump function. This process is called pickling. The process of retrieving original Python objects from the stored string representation is called unpickling. 

3. How is Python interpreted? 

Ans. Python language is an interpreted language. Python program runs directly from the source code. It converts the source code that is written by the programmer into an intermediate language, which is again translated into machine language that has to be executed. 

4. How is memory managed in Python? 

Ans. Python memory is managed by Python private heap space. All Python objects and data structures are located in a private heap. The programmer does not have access to this private heap and the interpreter takes care of this Python private heap. • The allocation of Python heap space for Python objects is done by Python memory manager. The core API gives access to some tools for the programmer to code. • Python also has an inbuilt garbage collector, which recycles all the unused memory, frees up memory, and makes it available to the heap space.

5. What is the difference between list and tuple? 

Ans. The difference between list and tuple is that list is mutable while tuple is not. Tuple can be further implemented as a key to dictionaries. 

6. What are the built-in types that Python provides? 

Ans. There are mutable and immutable types of Python built-in types. Mutable built-in types offered by Python are: • List • Sets • Dictionaries Immutable built-in types are: • Strings • Tuples • Numbers 

7. What is namespace in Python? 

Ans. In Python, every name introduced has a place where it lives and can be looked for. This is known as namespace. It is like a box where a variable name is mapped to the object placed. Whenever the variable is searched, this box will be searched to get the corresponding object. 

8. What is lambda in Python? 

Ans. It is a single expression, anonymous function often used as inline function.

9. What is pass in Python? 

Ans. Pass means no-operation Python statement or, in other words, it is a placeholder in compound statement, where there should be a blank left and nothing should be written there. 

10. What is slicing in Python? 

Ans. A mechanism to select a range of items from sequence types like list, tuple, strings, etc., is known as slicing. 

11. What is docstring in Python? 

Ans. A Python documentation string is known as docstring. It is a way of documenting Python functions, modules and classes.

12. What is negative index in Python? 

Ans. Python sequences can be indexed using both the positive and negative numbers. For positive index, 0 is the first index, 1 is the second index, so on and so forth. For negative index, (–1) is the last index and (–2) is the second last index and so on and so forth. 

13. How can you convert a number into a string? 

Ans. In order to convert a number into a string, use the inbuilt function str(). If you want an octal or hexadecimal representation, use the inbuilt function oct() or hex(). 

14. What do you understand by module and package in Python? 

Ans. In Python, module is the way to structure a program. Each Python program file is a module which imports other modules like objects and attributes. The folder of a Python program is a package of modules. A package can have modules or sub-folders. 

15. What are the rules for local and global variables in Python? 

Ans. Local variables: If a variable is assigned a new value anywhere within a function’s body, it is assumed to be local. Global variables: Those variables that are only referenced inside a function are implicitly global. 

16. Explain how to delete a file in Python. 

Ans. A file can be deleted by using a command os.remove (filename) or os.unlink(filename) 

17. Explain how you can generate random numbers in Python. 

Ans. To generate random numbers in Python, you need to import command as: import random random.random() This returns a random floating point number in the range [0,1) 

18. What is the use of // operator in Python? 

Ans. It is a Floor Division operator which is used for dividing two operands with the result as quotient showing only digits before the decimal point. For instance, 10//5 = 2 and 10.0//5.0 = 2.0. 

19. Mention five benefits of using Python. 

Ans. (a) Python comprises a huge standard library for most internet platforms like email, HTML, etc. (b) Python does not require explicit memory management as the interpreter itself allocates memory to new variables and frees them automatically. (c) Provides easy readability due to the use of square brackets. (d) Easy-to-learn for beginners. (e) Having the built-in data types saves programming time and effort from declaring variables. 

20. Mention the use of the split function in Python. 

Ans. The use of split function in Python is that it breaks a string into shorter strings using the defined separator. It gives a list of all words present in the string. 

21. What are literals in Python? 

Ans. Python literals can be defined as data which can be assigned to a variable or constant. There are 5 types of literals available in Python: • String literals • Numeric literals • Boolean literals • Special literals • Literal Collections 

22. Explain Python functions. 

Ans. A function is a set of instructions or a block of code that is written once and can be called and executed whenever required in the program. There are two categories of functions in Python: • Built-in functions • User-defined functions 

23. Name the different file processing modes supported by Python. 

Ans. Python provides three modes to work with files: • Read-only mode • Write-only mode • Read-Write mode 

24. What is an operator in Python? 

Ans. An operator is a particular symbol which is used on some values and produces an output as result. For example, 10 + 30 = 40 Here, “+” and “=” are operators. 

25. What are the different types of operators in Python?

Ans. Following is a list of operators in Python: • Arithmetic Operators • Relational Operators • Assignment Operators • Logical Operators • Membership Operators • Identity Operators • Bitwise Operators 

26. What is a Dictionary in Python? 

Ans. Dictionary is an important built-in data type in Python. It defines one-to-one relationship between keys and values. Dictionaries contain a pair of keys and their corresponding values. Dictionaries are indexed by keys. 

27. What is the use of HELP() and DIR() function in Python? 

Ans. Both Help() and dir() functions are accessible from the Python interpreter and used for viewing a consolidated collection of built-in functions. Help(): The help() function is used to display the documentation string and also facilitates you to see the help related to modules, keywords, attributes, etc. Dir(): The dir() function is used to display the defined symbols. 

28. How does Python do compile-time and run-time code checking? 

Ans. In Python, some amount of coding is done at compile-time, but most of the checking such as type, name, etc., is held up until the code execution. Consequently, if the Python code references a user-defined function that does not exist, the code will compile successfully. The Python code will fail only with an exception when the code execution path does not exist. 

29. Explain the use of TRY: EXCEPT: RAISE: and FINALLY:.

Ans. Try, except and finally blocks are used in Python error-handling mechanism. Code is executed in the try block until an error occurs. Except block is used to receive and handle all errors. Control is transferred to the appropriate except block. In all cases, the finally block is executed. Raise may be used to raise your own exceptions. 

30. What is the purpose of PYTHONPATH environment variable? 

Ans. PYTHONPATH has a role similar to PATH. This variable tells the Python interpreter where to locate the module files imported into a program. It should include the Python source library directory and the directories containing Python source code. 

31. What are the supported data types in Python? 

Ans. Python has five standard data types: • Numbers • String • List • Tuple • Dictionary 

32. What is the difference between lists and tuples? 

Ans. Lists Tuples Lists are mutable, i.e., they can be edited. Tuples are immutable (tuples are lists which can’t be edited). Lists are slower than tuples. Tuples are faster than lists. Syntax: list1 = [10, ‘Python’, 44.5] Syntax: tup1 = (10, ‘Python’ , 44.5) 

33. How will you reverse a list? 

Ans. list.reverse() − Reverses items of list in place. 

34. What is a string in Python? 

Ans. A string in Python is a sequence of alphanumeric characters. They are immutable objects. It means that they don’t allow modification once they are assigned a value. Python provides several methods such as join(), replace(), or split() to alter strings.

35. Why is the Return keyword used in Python? 

Ans. The purpose of a function is to receive the inputs and return some output. The return is a Python statement which we can use in a function for sending a value back to its calling function or the operating system. 

36. When should you use the “Break” in Python? 

Ans. Python provides a break statement to exit from a loop. Whenever the break hits in the code, the control of the program immediately exits from the body of the loop. The break statement in a nested loop causes the control to exit from the inner iterative block. 

37. What is a tuple in Python? 

Ans. A tuple is a collection of type data structure in Python which is immutable. Tuples are similar to sequences, just like the lists. However, there are some differences between a tuple and a list—the former doesn’t allow modifications, the latter does. Also, the tuples use parentheses for enclosing but the lists have square brackets in their syntax. 

38. How do you debug a program in Python? Is it possible to step through the Python code?

Ans. Yes, we can use the Python debugger (pdb) to debug any Python program. If we start a program using pdb, then it lets us even step through the code. 

39. List down some of the PDB commands for debugging Python programs. 

Ans. Here are a few PDB commands to start debugging Python code: • Add breakpoint (b) • Resume execution (c) • Step-by-step debugging (s) • Move to the next line (n) • List source code (l) • Print an expression (p) 

40. Explain the use of “with” statement.

Ans. In Python, generally “with” statement is used to open a file, process the data present in the file, and also to close the file without calling a close() method. “with” statement makes the exception handling simpler by providing cleanup activities. General form of with: with open(“filename”, “mode”) as file-var: processing statements 

41. How can we display the contents of text file in reverse order? 

Ans. (a) Convert the given file into a list. (b) Reverse the list by using reversed() (c) Eg: for line in reversed(list(open(“file-name”,”r”))) (d) print(line) 

42. Differentiate between append() and extend() methods. Ans. Both append() and extend() methods are methods of list. These methods are used to add elements at the end of the list. • append(element) – adds the given element at the end of the list which has called this method. • extend(another-list) – adds the elements of another list at the end of the list which is called the extend method. 

43. What are the advantages of Python recursion? 

Ans. Implementing something using Python recursion requires less effort. The code we write using recursion will be comparatively smaller than the code that is implemented by loops. Again, codes that are written using recursion are easier to understand also. 

44. What do you understand by Python modules? 

Ans. A file containing Python definitions and statements is called a Python module. So naturally, the filename is the module name which is appended with the suffix .py. 

45. What do you understand by Python package? 

Ans. Python package is a collection of modules in directories that gives a package hierarchy. More elaborately, Python packages are a way of structuring Python’s module by using “dotted module names”. So A.B actually indicates that B is a sub-module which is under a package named A. 

46. How can we get current directory using Python? 

Ans. To get current directory in Python, we need to use os module. Then, we can get the location of the current directory by using getcwd() function. 

47. What is the difference between del keyword and clear() function? 

Ans. The difference between del keyword and clear() function is that while del keyword removes one element at a time, clear function removes all the elements. 

48. What is primary key? 

Ans. Primary key is a combination of columns that uniquely identifies a row in a relational table. 

49. What is candidate key? 

Ans. All possible combinations of columns that can possibly serve as the primary key are called candidate keys. 

50. What is foreign key? 

Ans. A combination of columns where values are derived from primary key of some other table is called the foreign key of the table in which it is contained. 

51. What is alternate key? 

Ans. A candidate key that is not serving as a primary key is called an alternate key. 

52. What is MYSQL? 

Ans. MYSQL is an open source RDBMS that relies on SQL for processing the data in the database. The database is available for free under the terms of General Public License (GPL). 

53. What is RDBMS? 

Ans. Relational Database Management System (RDBMS) facilitates access, security and integrity of data and eliminates data redundancy. For example, MYSQL, Oracle, Microsoft Sql Server, etc.

54. What is the use of drop command? 

Ans. Drop command is used to delete tables. For example, Drop Table Orders. Delete commands are used to delete rows of a table. 

55. What do you understand by NOT NULL constraint? 

Ans. This constraint ensures that the null values are not permitted on a specified column. This constraint can be defined at the column level and not at the table level. 

56. What is the significance of COUNT? 

Ans. It is used to count the number of values in a given column or number of rows in a table. For example, Select count (Roll No.) from students. 

57. How can we delete a table in MYSQL? 

Ans. We can delete a table in MYSQL using the drop command. 

58. How can we delete a record in MYSQL? 

Ans. We can delete a record in MYSQL using the delete command. 

59. How can we add a record and add a column in a table? 

Ans. We can add a record by using insert command and we can add a column through the alter table command. 

60. Give any two differences between GET and POST submission methods of HTML form. 

Ans. GET Method POST Method All form data is encoded into the URL appended to the action URL as query string parameters. Form data appears within the message body of the HTTP request. Parameters remain in browser history, hence cannot be used to send password like sensitive information. Parameters are not saved in browser history, hence can be used to send sensitive information. Can be bookmarked. Cannot be bookmarked. Easier to hack for script kiddies. More difficult to hack. Can be cached. Cannot be cached. 

61. Give the necessary command to incorporate SQL interface within Python. 

Ans. import MySQLdb 

62. What is Django? 

Ans. Django is a high-level Python web framework that encourages rapid development and clean, pragmatic design. Developed by a fast-moving online news operation, Django was designed to handle two challenges: the intensive deadlines of a newsroom and the stringent requirements of the experienced web developers who wrote it. It lets you build high-performing, elegant web applications quickly.

What Are the Benefits of Power BI?

 Key Benefits of Power BI

Running a company requires constant decision-making. The company's leader lacks the necessary control over a decision and does it as best as they can, or even by mistake.

The benefits of Power BI are numerous, and it aids management teams in making fast decisions without jeopardizing the company's profitability. Data visualization is made simple with Power BI. It has a full summary of company data in visual form, with display choices such as tables, charts, gauges, and maps. This makes it easier for teams to use.

Power BI helps companies be more efficient, agile, and flexible by making it easy to see results. Power BI is a powerful business intelligence and data visualization tool developed by Microsoft. It offers a range of benefits that make it popular for data analysis and reporting:

1. Data Visualization: Power BI enables you to create compelling visualizations, charts, graphs, and dashboards from your data. These visuals are interactive and provide insights that are easy to understand, making it simpler to communicate complex information.
2. Data Connectivity: Power BI allows you to connect to a wide variety of data sources, including databases, cloud services, spreadsheets, and APIs. This flexibility enables you to bring together data from different sources for comprehensive analysis.
3. Real-Time Dashboards: With Power BI's real-time capabilities, you can create live dashboards that display data updates as they happen. This is especially valuable for tracking key performance indicators and making data-driven decisions in real time.
4. Data Transformation: Power Query, a component of Power BI, offers data transformation capabilities, allowing you to clean, reshape, and combine data from multiple sources before analysis. This helps ensure data accuracy and quality.
5. Natural Language Queries: Power BI supports natural language queries, allowing users to ask questions about their data using everyday language. This feature makes data exploration more intuitive and accessible to users who may not have technical expertise.
6. Data Modeling: The Power BI data modeling engine lets you create relationships between different data tables, define calculations, and create measures. This enables you to perform advanced calculations and build complex data models for in-depth analysis.
7. Collaboration and Sharing: Power BI facilitates collaboration by allowing users to share reports and dashboards with colleagues and stakeholders. Reports can be published to the Power BI service or embedded in other applications, promoting information sharing.
8. Mobile Accessibility: Power BI offers mobile apps for various platforms, allowing users to access reports and dashboards on smartphones and tablets. This ensures that decision-makers can stay informed even while on the go.
9. Security and Compliance: Power BI provides robust security features, including role-based access control, data encryption, and integration with Azure Active Directory. This helps ensure that data remains secure and compliant with organizational policies.
10. Scalability: Power BI is designed to handle large datasets and can scale to accommodate growing data needs. It can also integrate with other Microsoft services like Azure for enhanced scalability.
11. Customization and Extensions: Power BI allows developers to create custom visuals, extensions, and custom connectors, enabling organizations to tailor the platform to their specific needs.
12. Cost-Effectiveness: Power BI offers various pricing tiers, including a free version with limited features. This makes it accessible to a wide range of users and organizations, including small businesses.

Overall, Power BI's capabilities in data visualization, analysis, and sharing contribute to better decision-making, improved data insights, and enhanced business performance.

POWER BI QUESTIONS PART 4

 

Power BI Interview Questions For Experienced

1. What are the types of visualizations in Power BI?

Visualization is a graphical representation of data. We can use visualizations to create reports and dashboards. The kinds of visualizations available in Power BI are Bar charts, Column charts, Line chart, Area chart, Stacked area chart, Ribbon chart, Waterfall chart, Scatter chart, Pie chart, Donut chart, Treemap chart, Map, Funnel chart, Gauge chart, Cards, KPI, Slicer, Table, Matrix, R script visual, Python visual, etc.

2. What do we understand by Power BI services?

Power BI provides services for its cloud-based business analytics. With these services, you can view and share reports via the Power BI website. Power BI is a web-based service for sharing reports. Power BI service can be best referred to as PowerBI.com, PowerBI workspace, PowerBI site, or PowerBI portal.

3. What is the comprehensive working system of Power BI?

Power BI’s working system mainly comprises three steps:

• Data Integration: The first step is to extract and integrate the data from heterogeneous data sources. After integration, the data is converted into a standard format and stored in a common area called the staging area.
• Data Processing: Once the data is assembled and integrated, it requires some cleaning up. Raw data is not so useful therefore, a few transformation and cleaning operations are performed on the data to remove redundant values, etc. After the data is transformed, it is stored in data warehouses.
• Data Presentation: Now that the data is transformed and cleaned, it is visually presented on the Power BI desktop as reports, dashboards, or scorecards. These reports can be shared via mobile apps or web to various business users.

4. What are custom visuals in Power BI?

Using Power BI visualizations, you can apply customized visualizations like charts, KPIs, etc. from the rich library of PowerBI’s custom visuals. It refrains the developers from creating it from scratch using JQuery or Javascript SDK. Once the custom visual is ready, it is tested thoroughly. Post testing, they are packaged in .pbiviz file format and shared within the organization.

Types of visuals available in Power BI are:

• Custom visual files.
• Organizational files.
• Marketplace files.

5. What are the various type of users who can use Power BI?

Anyone and everyone can use PowerBI to their advantage. But even then a specific set of users are more likely to use it viz:

• Business Users: Business users are the ones who constantly keep an eye on the reports to make important business decisions based on the insights.
• Business Analysts: Analysts are the ones who create dashboards, reports, and visual representations of data to study the dataset properly. Studying data needs an analytical eye to capture important trends within the reports.
• Developers: Developers are involved while creating custom visuals to create Power BI, integrating Power BI with other applications, etc. 
  Professionals: They use Power BI to check the data scalability, security, and availability of data.

POWER BI Questions Part 3

Power BI Intermediate Questions

1. What is a dashboard?

The dashboard is like a single-page canvas on which you have various elements to create and visualize reports created by analyzing data. It comprises only the most important data from the reports to create a story.

The visual elements present on the dashboard are called Tiles. You can pin these tiles from the reports to the dashboard. Clicking any element on the dashboard takes you to the report of a particular data set.

2. What are the building blocks of Power BI?

The major building blocks of Power BI are:

• Datasets: Dataset is a collection of data gathered from various sources like SQL Server, Azure, Text, Oracle, XML, JSON, and many more. With the GetData feature in Power BI, we can easily fetch data from any data source.
• Visualizations: Visualization is the visual aesthetic representation of data in the form of maps, charts, or tables.
• Reports: Reports are a structured representation of datasets that consists of multiple pages. Reports help to extract important information and insights from datasets to take major business decisions.
• Dashboards: A dashboard is a single-page representation of reports made of various datasets. Each element is termed a tile. 
  Tiles: Tiles are single-block containing visualizations of a report. Tiles help to differentiate each report.

3. What are content packs in Power BI?

Content packs are packages comprising different Power BI objects such as reports, dashboards, datasets, etc. The two types of content packs are:

Service provider content packs: Service providers such as Google Analytics, Salesforce, etc. provide pre-built content packages

User-created content packs: Users can create their content packages and share them within the organization.

4. What are the various Power BI versions?

The three major versions of Power BI are as follows:

• Power BI Desktop: The free interactive tool that connects multiple data sources, transforms data, and creates visualized reports.
• Power BI Premium: The premium version is used for larger organizations with a dedicated storage capacity for each user. With premium, data sets up to 50GB storage capacity can be hosted along with 100TB storage on the cloud as a whole. It costs $4995 per month.
• Power BI Pro:  With the pro version, you get full access to the Power BI dashboard, creation of reports, along with unlimited sharing and viewing of reports. You also have a storage limit of 10GB per user.

5. What is DAX?

Data Analysis Expression (DAX) is a library of formulas used for calculations and data analysis. This library comprises functions, constants, and operators to perform calculations and give results. DAX lets you use the data sets to their full potential and provide insightful reports.

DAX is a functional language containing conditional statements, nested functions, value references, and much more. The formulas are either numeric (integers, decimals, etc.) or non-numeric (string, binary). A DAX formula always starts with an equal sign.

6. What are the purpose and benefits of using the DAX function?

DAX is much more than Power BI. If you learn DAX as a functional language, you become better as a data professional. DAX is based on different nested filters which magnificently improves the performance of data merging, modeling, and filtering tables.

7. What is Power Pivot?

Power Pivot enables you to import millions of rows from heterogeneous sources of data into a single excel sheet. It lets us create relationships between the various tables, create columns, calculate using formulas, and create PivotCharts and PivotTables.

At a time there can be only one active relationship between the tables which is represented by a continuous line.

8. What is Power Query?

Power query is a function that filters transforms, and combines the data extracted from various sources. It helps to import data from databases, files, etc and append data

9. Difference between Power BI and Tableau?

The major differences between Power BI and Tableau are:

• While Power BI uses DAX for calculating columns of a table, Tableau uses MDX (Multidimensional Expressions).
• Tableau is more efficient as it can handle a large chunk of data while Power BI can handle only a limited amount. 
• Tableau is more challenging to use than Power BI.

10. What is GetData in Power BI?

GetData offers data connectivity to various data sources. Connect data files on your local system. The supported data sources are:

• File: Excel, Text/CSV, XML, PDF, JSON, Folder, SharePoint.
• Database: SQL Server database, Access database, Oracle database, SAP HANA database, IBM, MySQL, Teradata, Impala, Amazon Redshift, Google BigQuery, etc.
• Power BI: Power BI datasets, Power BI dataflows.
• Azure: Azure SQL, Azure SQL Data Warehouse, Azure Analysis Services, Azure Data Lake, Azure Cosmos DB, etc.
• Online Services: Salesforce, Azure DevOps, Google Analytics, Adobe Analytics, Dynamics 365, Facebook, GitHub, etc.
• Others: Python script, R script, Web, Spark, Hadoop File (HDFS), ODBC, OLE DB, Active Directory, etc.

11. What are filters in Power BI?

Filters sort data based on the condition applied to it. Filters enable us to select particular fields and extract information in a page/visualization/report level. For example, filters can provide sales reports from the year 2019 for the Indian region.  Power BI can make changes based on the filters and create graphs or visuals accordingly. Types of filters are:

• Page-level filters: These are applied on a particular page from various pages available within a report.
• Visualization-level filters: These are applied to both data and calculation conditions for particular visualizations.
• Report-level filters: These are applied to the entire report.

POWER BI Questions Part 2

 

What is Power BI?

Power BI was introduced by Microsoft to combine the multiple data visualization features into one. Power BI is the new term for the data-driven industry and thus carries a lot of opportunities on its shoulders.  It comes as a package of three major components:

• Power BI services
• Power BI Desktop
• Power BI mobile app

With these three components, Power BI lets you create a data-driven insight into your business. Based on various roles, you can leverage Power BI to your benefits like creating reports, monitor progress, integrate APIs, and many more.

Why Power BI?

Power BI has simplified the workaround of getting data from various sources and collating them into one tool for proper management. We can share these interactive reports for different industries like retail, for free.

Power BI is the new flash word in the data-driven tech industry today. The power BI opportunities are umpteen and spread across versions. With proper knowledge of the tool you can easily grab opportunities as a:

• Power BI data analyst
• Power BI developer
• Power BI software engineer
• Power BI project manager
• SQL Server Power BI developer
• Power BI consultant

With good compensation, you get to work with a product’s data and learn about its insights to make important decisions. Not just this, with the latest Gartner’s BI and Analytics report, Power BI has emerged as the winner. With so much hype, learning Power BI is worth it.

In today's article, we will be looking at the interview questions on Power BI from basic, intermediate, to advanced levels.

Power BI Interview Questions For Freshers

1. How would you define Power BI as an effective solution?

Power BI is a strong business analytical tool that creates useful insights and reports by collating data from unrelated sources. This data can be extracted from any source like Microsoft Excel or hybrid data warehouses. Power BI drives an extreme level of utility and purpose using interactive graphical interface and visualizations. You can create reports using the Excel BI toolkit and share them on-cloud with your colleagues.

2. What are the major components of Power BI?

Power BI is an amalgamation of these major components:

Components of Power BI

• Power Query (for data mash-up and transformation): You can use this to extract data from various databases (like SQL Server, MySql, and many others ) and to delete a chunk of data from various sources.
• Power Pivot (for tabular data modeling): It is a data modeling engine that uses a functional language called Data Analysis Expression (DAX) to perform the calculations. Also, creates a relationship between various tables to be viewed as pivot tables.
• Power View (for viewing data visualizations): The view provides an interactive display of various data sources to extract metadata for proper data analysis.
• Power BI Desktop (a companion development tool): Power Desktop is an aggregated tool of Power Query, Power View, and Power Pivot. Create advanced queries, models, and reports using the desktop tool.
• Power BI Mobile (for Android, iOS, Windows phones): It gives an interactive display of the dashboards from the site onto these OS, effortlessly.
• Power Map (3D geo-spatial data visualization).
• Power Q&A (for natural language Q&A).

3. What are the various refresh options available?

Four main refresh options are available in Power BI:

• Package/OneDrive refresh: This synchronizes Power BI desktop or Excel file between the Power BI service and OneDrive
• Data/Model refresh: This means scheduling the data import from all the sources based on either refresh schedule or on-demand. 
• Tile refresh: Refresh the tiles’ cache on the dashboard every time the data changes.
• Visual container refresh: Update the reports’ visuals and visual container once the data changes.

4. What are the different connectivity modes in Power BI?

The three major connectivity modes in Power BI are:

Direct Query: The method allows direct connection to the Power BI model. The data doesn’t get stored in Power BI. Interestingly, Power BI will only store the metadata of the data tables involved and not the actual data. The supported sources of data query are:

• Amazon Redshift
• Azure HDInsight Spark (Beta)
• Azure SQL Database
• Azure SQL Data Warehouse
• IBM Netezza (Beta)
• Impala (version 2.x)
• Oracle Database (version 12 and above)
• SAP Business Warehouse (Beta)
• SAP HANA
• Snowflake
• Spark (Beta) (version 0.9 and above)
• SQL Server
• Teradata Database

Live Connection: Live connection is analogous to the direct query method as it doesn’t store any data in Power BI either. But opposed to the direct query method, it is a direct connection to the analysis services model. Also, the supported data sources with live connection method are limited:

• SQL Server Analysis Services (SSAS) Tabular
• SQL Server Analysis Services (SSAS) Multi-Dimensional
• Power BI Service

Import Data (Scheduled Refresh): By choosing this method, you upload the data into Power BI. Uploading data on Power BI means consuming the memory space of your Power BI desktop. If it is on the website, it consumes the space of the Power BI cloud machine. Even though it is the fastest method, the maximum size of the file to be uploaded cannot exceed 1 GB until and unless you have Power BI premium (then you have 50 GB at the expense). 

But which model to choose when depends on your use and purpose.

5. What is a Power BI desktop?

To access the Power BI features, visualize data, or model them to create reports, you can simply download a desktop version of Power BI. With the desktop version, you can extract data from various data sources, transform them, create visuals or reports, and share them using Power BI services.

6. Where is the data stored in Power BI?

Primarily, Power BI has two sources to store data:

Azure Blob Storage: When users upload the data, it gets stored here.
Azure SQL Database: All the metadata and system artifacts are stored here.

They are stored as either fact tables or dimensional tables.

7. What are the available views?

In power BI, you have various kinds of views viz:

• Data View: Curating, exploring, and viewing data tables in the data set. Unlike, Power Query editor, with data view, you are looking at the data after it has been fed to the model.
• Model View: This view shows you all the tables along with their complex relationships. With this, you can break these complex models into simplified diagrams or set properties for them at once.
• Report View: The report view displays the tables in an interactive format to simplify data analysis. You can create n number of reports, provide visualizations, merge them, or apply any such functionality.

8. What are the available formats?

Power BI is available in various formats:

• Power BI desktop: For the desktop version
• Power BI mobile app: For using the visualizations on mobile OS and share it
• Power BI services: For online SaaS

9. Power BI can connect to which data sources?

The data source is the point from which the data has been retrieved. It can be anything like files in various formats (.xlsx, .csv, .pbix, .xml, .txt etc), databases (SQL database, SQL Data Warehouse, Spark on Azure HDInsight), or form content packets like Google Analytics or Twilio.

Power BI Interview Questions Part -1

 

 

POWER BI INTERVIEW QUESTIONS

1.      What is Difference between PowerBI and Tableau?

 Tableau is primarily a data visualization Tool, PowerBI is both ETL and Data Visualization Tool ,it  also has lot of data modelling options Power BI is a tool use for easy visualization and is freely available for desktop version and can be use standalone. It has ETL tools which are similar to Excel Power Query which make it easy and comfortable It also can add external visuals to make the report attractive and interactive, Tableau is a Similar Visualization Tool but is paid version although no additional visual is needed to be added but to create the visual in tableau, it requires good skill and understanding of charts and tableau tools.

2.  Which are the other Data Visualization Tools in Market ?

        Google Data Studio, Excel Power Pivot, Power Map, SAP Business Objects BI Suite, TIBCO Spotfire, Looker, Tableau, QlikView, Plotly, IBM Whatson.

 

3.       What is ETL ?

ETL Stands for Extract Transform Load, ETL tools are used to convert raw data into structured tabular format, and which records the steps performed which can be applied automatically on future loaded files.

 

4.       Which is the ETL Component of POWERBI ?

Power Query is the ETL part of PowerBI additionally the same tool is available in excel as well.

 

5.       Describe the different components of PowerBI ?

PowerBI Desktop - PowerQuery – PowerPivot – PowerView – PowerBI Service – PowerBI MobileApps, Power BI Data Flow, Power Map, Power Q&A.

 

6.       Which are the other ETL Tools in Market ?

Informatica PowerCenter, Abinitio, Alteryx, SSIS, Spotfire, IBM DataStage, Oracle Data Integrator, SAS Data Management, Talend Open Studio, Pentaho Data Integration, Singer, Hadoop, etc.

 

7.       What are the different data sources connectivity available in PowerBI ?

PowerBI offers more than 300 different data sources support . Excel ,CSV,JSON,Folder,Web,PDF,SQL Server,MYSQL,Azure SQL Database,SAP HANA,Amazon RedShift,Teradata are some of the common data sources

 

8.       What is PowerBI, why is it used for ?

Power BI is a Business Intelligence Tool, It is collection of software services, apps, and connectors that work together to turn your unrelated sources of data into coherent, visually immersive, and interactive insights

 

9.       What is the difference between Direct Query mode and Import Mode ?

A Direct Query connection will run queries directly to your source at run time/Realtime. In the Import method, Power BI captures a snapshot of your data and caches it in Power BI Desktop.

 

10.   What is the advantage of Import Mode over Direct Query Mode ?

As the data is cached in Import Mode,Refresh time is faster in Import Mode compared to Direct query mode ,Although many transformations in PowerQuery and some DAX functions wont work in Direct Query Mode

 

11.   What is the advantage of Direct Query Mode over Import Mode?

Since the Data is stored at the Source in Direct Query Mode not in POWERBI Cache, we can overcome the POWERBI Size limitations for data and we get Live data as we can set timer of refresh as low as 5 sec

 

12.   What is dual mode in Power BI?

 The dual storage mode is between Import and Direct Query. it is a hybrid approach, Like importing data, the dual storage mode caches the data in the table

 

13.   What Language does Power Query use ?

M Language or Mash up Language

 

14.   What are the different formats in which PowerBI is available ?

PowerBI Desktop,PowerBI Service,PowerBI Mobile App

 

15.   Where is the data stored in PowerBI ?

Azure Blob Storage, Azure SQL Database and other cloud base storage depends on Microsoft Tieups.

 

16.    What are the available views ?

Report View,Data View,Modelling View

 

17.   What is PowerQuery ?

PowerQuery is the ETL Component of PowerBI Which is used to connect multiple data sources and do some transformations also referred as data cleaning or data massaging

 

18.   Describe Merge Query from Transform tab in PowerQuery ?

Merge Query is used to combine data from different tables based on common column, It is similar to joins in SQL and VLOOKUP from Excel.

19.   What are the different types of Joins there in Merge Query?

Inner Join,Left Join,Right Join,Full Join,Left Anti,Right Anti

 

20.   What is Inner Join in Merge Query ?

 Inner join returns all Matching Rows from both Tables