SQL Server: Common Interview Questions

1. What is the difference between Delete and Truncate in SQL Server?
2. What is trigger? Write syntax of trigger.
3. What is the difference between “char” and “varchar”?
4. What is function in Sql server? How many types of functions?
5. What is stored procedure? Write syntax of stored procedure?
6. How parameter is passed to sql function and how call a function?
7. What is input and output parameter in stored procedure? How it works?
8. Write syntax to create a table.
9. What is view? What is the difference between table and view?
10. What is constraint? Tell different type of constraint and its functionality.
11. Discuss different type of joining. How it works?
12. How left outer joining works?
13. How inner join works? Give an example.
14. How outer join works? Give an example.
15. How right outer join works? Give an example.
16. How full outer join works? Give an example?
17. How Cross Join works? Give an example?
18. Which one faster – Inner join or Cross Join?
19. How do you move all data to another table using query?
20. Find out the maximum salary from a salary table?
21. How do you find number of employee from employee table?
22. What is commit and rollback? How it works?
23. What do you know about transaction block? How it works?
24. How primary key constraints, foreign key constraints and default constraints works?
25. How not null constraints, check constraints, rules constraint and unique constraints works?
26. What are DDL and DML? Give example.
27. How distinct keyword works?
28. What do you know about sql wildcard? Give example.
29. How to select top 10 employees from employee table?
30. How “between” and “in” operator works?
31. Union / Union all, requirement and difference.
32. What is sub query? Give an example.
33. How “having” clause works?
34. How “group by” clause works?
35. Why “Where” clause is needed?

C# - Common interview questions

1. What is value type and reference type?
2.  What is the use of dispose method?
3. Give an example of method overloading and method overriding?
4. What is class? Give a real life example.
5. What is Object? Give a real life example.
6. What is abstract class?
7. Why partial class?
8. What is predefined data type and user defined data type? Discuss with example.
9. What is verbatim string? How it works?
10. What is the difference between string and string builder?
11. Why and how constant is used in C#?
12. What is enumeration type? How it works?
13. What do you know implicit and explicit conversion? Give an example.
14. How switch statement works? What is the function of default in switch case?
15. How break and continue keyword works? Give an example.
16. What is the difference in for loop, while loop and do while loop?
17. What is boxing and unboxing?
18. What do you know about namespace and nested namespace? Why namespace is used?
19. How parameter is passed by reference? Give an example.
20. What is constructor? What is constructor overloading?
21. Why constructor is used?
22. Why read only variable is used?
23. What is the difference between read only and constant variable?
24. What is static class? Why static class is used?
25. What is inheritance? Why is it necessary?
26. What is sealed class? Why sealed class is used?
27. What is abstract class?
28. What is the difference between abstract class and interface?
29. Is there any difference between “ ++I”  and “i++”? How it works?

Professional Email Writing Etiquette

We often fell in a problem to write professional email. Actually professional email is much more different than casual or instant messenger. You can easily manage your employer or boss by email. On the contrary, it might be the cause of annoyance of your employer or manager. Now email is very popular in Job process. So, you must think before sending the email. You should read the content again before clicking the send button of email. I firmly believe that it is very easy to rule out than rule in. Here is some email writing tips:

Mind your manner:

Don’t forget to use basic polite word – thank you and please.

·         Introduce yourself as like you mentioned in cover letter. Example -

Dear Mr./Ms.

Or Dear Sir/Madam,

Because you don’t exactly know the gender of your mail recipient. If you exactly know your recipient gender then you can write either one.

·         In the subject of the mail, choose suitable title – why you are writing. Example – “Application for the post of Software Engineer” or “Application for Software Engineer Post”

·         It is our nature that we always just copy and pest the same email to multiple recipients. If you do this, make sure that the contact information of your recipient is correct.  Suppose,

To,

HR Manager

LEADS Corporation Limited

·         If you are responding to an email, include the original message in the reply, so the receiver can put your email in the correct context.

·         Name you document like “your name_resume”. Employer receives lots of mail via email. You follow up your recruiters, If they received your mail. It is almost impossible to find out your CV from the hundreds email attachment.

·         Attach your CV format as recruiter wants. You can attach your cv in (pdf, rtf, doc) format.

Be formal, be professional:

·         Never use all capital letter. It is always difficult to read.

·         Always think your employer is formal.

·         Stay away from using abbreviation.

·         Don’t use emoticons (Smily faces).

·         It is always seen that sender uses some unprofessional sounding name for email such as – sweetheart132@gmail.com, hatehim223@yahoo.com.  It will be a negative impact on the employer. Employer will get a negative idea about your interest from this mail address. Always avoid this type of email address.

·         Don’t use slang.

Be concise:

·         Email should be concise and short. Most of the time receiver don’t have patient to read a long email.  But keep in mind, to make it short, don’t leave any important details.

·         Before sending email – check your spelling and grammar. It’s better to review your email by others.

Sample Email

To: karim@xyzcompany.com       

From: tapu@yahoo.com 

Subject: Application for the post of Software Engineer 

Dear Sir/Madam, 

This email is in response to the ad posted in the bdjobs.com for the Software engineer position at xyz Company (Job Posting #123). Please accept the attached letter and resume as my application for thisposition. My skills and experience closely fit the posted job description, and I hope to hear from you soon. 

Thank you, 

Md. Tapu Rahman

Dhaka - 1204

tapu@yahoo.com

 This is a sample and simple email. You should not think it as standard. I think, you will write better than this.

How to find pen drive hidden folder

Sometimes due to virus attack, our pen drive data is hidden.  We think, all folders are deleted. So, check first before you format your Usb otherwise you will lose your data forever.  Sometimes hidden files are not displayed even if you "Show hidden files and folders" in the Folders Options. To find hidden folder in your pen drive. Just run the following command in your command window.

attrib -h -r -s /s /d g:\*.*

For accurate command just copy the above command and pest it. Here g: is considered your pen drive.  Replace g by your pen drive “drive letter”

Basic concepts of Business Intelligence (BI)

What is BI?

Business Intelligence (BI) is a computer based technique to identified, extracting (*1) and analyzing business data. For example senior management of an industry can inspect sales revenue by products and/or departments, or by associated costs and incomes. BI technologies provide historical, current and predictive views of business operations. So, management can take some strategic or operation decision easily.

Why BI?

BI is used for reporting, online analytical processing, data mining, process mining, complex event processing, business performance management, benchmarking, text mining and productive analysis .By using BI, management can monitor objectives from high level , understand what is happening, why is happening and can take necessary steps why the objectives are not full filled. Business intelligence aims to support better business decision-making. Thus a BI system can be called a decisions support system (DSS).

Before going to launch any product, company need to understand of market trend. Company uses BI to analyze market data and understand which product or which business is suitable for the current time in the market. In a word, BI gives you right information, right time in right format.

Suppose a software company wants to develop an ERP. Before going to develop an ERP, company’s business executive need to better understand of its development cost. Potentiality of it’s sells volume. Management need to understand that will it protect margins. To understand the above factors they have to have consolidated views of business. BI provides this visual and consolidates view. From this reports, company can take necessary action and can take decision whether they should develop an ERP or not.

Now suppose your ERP is developing and your management can see the current situation of the project. They have no time to see all the documents. They want to view the current status of the project from the top. This may be dashboard, BI provides this. So management can understand whether the product is developing cost effective way or not. BI can suggest corrective action against the data.

Sample sales Dashboard:

Prerequisites

Before implementing a BI solution, it is worth taking different factors into consideration before proceeding. According to Kimball et al., these are the three critical areas that you need to assess within your organization before getting ready to do a BI project.

1. The level of commitment and sponsorship of the project from senior management.

2. The level of business need for creating a BI implementation.

3. The amount and quality of business data available. Data can be gathered from Enterprise, department or individual.

How BI works?

BI uses technologies, processes, and applications to analyze mostly internal, structured data and business processes.

- Data warehousing and BI

Often BI applications use data gathered from a data warehouse or data mart. However, not all data warehouses are used for business intelligence, nor do all business intelligence applications require a data warehouse. In order to distinguish between concepts of business intelligence and data warehouses, Forrester Research often defines business intelligence in one of two ways:

Boarder Definition: "Business Intelligence is a set of methodologies, processes, architectures, and technologies that transform raw data into meaningful and useful information used to enable more effective strategic, tactical, and operational insights and decision-making.” When using this definition, business intelligence also includes technologies such as data integration, data quality, data warehousing, master data management, text and content analytics, and many others that the market sometimes lumps into the Information Management segment. Therefore, Forrester refers to data preparation and data usage as two separate, but closely linked segments of the business intelligence architectural stack.

Forrester defines the latter, narrower business intelligence market as "referring to just the top layers of the BI architectural stack such as reporting, analytics and dashboards."

- Business intelligence and business analytics

Thomas Davenport has argued that business intelligence should be divided into querying, reporting, OLAP, an "alerts" tool, and business analytics. In this definition, business analytics is the subset of BI based on statistics, prediction, and optimization.

Business Intelligence can be applied to the following business purposes (MARCKM), in order to drive business value:

MARCKM means – Measurement, Analytics, Reporting/Enterprise Reporting, Collaboration/Collaboration Platform, and Knowledge Management.

In addition to above, Business Intelligence also can provide a pro-active approach, such as ALARM function to alert immediately to end-user. There are many types of alerts, for example if some business value exceeds the threshold value the color of that amount in the report will turn RED and the Business Analyst is alerted. Sometimes an alert mail will be sent to the user as well. This end to end process requires data governance, which should be handled by the expert.

Semi-structured or unstructured data

Businesses collect a huge amount of valuable information. These information included in the form of e-mails, memos, notes from call-centers, news, user groups, chats, reports, web-pages, presentations, image-files, video-files, and marketing material and news.

BI uses both structured and unstructured data, but the former is easy to search, and the latter contains a large quantity of the information needed for analysis and decision making. It is very difficult to identify which information is in unstructured data. Unstructured and semi-structured data have different meanings depending on their context. In the context of relational database systems, it refers to data that cannot be stored in columns and rows. It must be stored in a BLOB(binary large object), a catch-all data type available in most relational database management systems. Since it is difficult to search information from unstructured data so, what will organization do to extract information from unstructured data?

Metadata is only way to search information from unstructured data. Metadata is actually data about data. Metadata can include information such as author and time of creation. This metadata can be stored in a database. So, it is easy to search by this metadata. To solve problems with search ability and assessment of data, it is necessary to know something about the content. It is more useful would be metadata about the actual content – e.g. summaries, topics, people or companies mentioned.

There are many challenges to develop BI with semi-structured and structured data. Those are:

- Accessing unstructured data because it is stored in a variety of format.

- There is no standard terminology.

- Volume of data is so high

- Search ability of unstructured data is not easy.

Many BI tools are available now. The information delivery model is given below.

Data can be collected from different source.ETL (Extract, transform and load) is responsible to collect these data. Then these data are kept in data warehouse by ETL. Data warehouse can be sub divided into Data marts. OLAP provides these data to the BI tools users by OLAP Cubes. BI tools display these result to the users.

BI Tools:

Many BI tools are available now. Most of the organization follows-

• Spreadsheet
• Reporting and querying software: tools that extract, sort, summarize, and present selected data
• Dashboards
• Data mining
• Data warehousing
• Decision Engineering
• Process Mining
• Business Performance management
• Local Information System

Microsoft introduced a new BI tool name-Dashboard. Dashboard is a visual display of the most important information needed to achieve one or more objectives which fits in a single computer screen so it can be monitored at a glance - Stephen Few, Information Dashboard design.

Microsoft BI Solution – 2007 architecture.

Notes:

1. Data extraction is the act or process of retrieving data out of (usually unstructured or poorly structured) data source for further data processing or data storage. The import into the intermediate extracting system is thus usually followed by data transformation and possibly the addition of metadata prior to export to another stage in the data workflow. Usually, the term data extraction is applied when (experimental) data is first imported into a computer from primary sources, like measuring recording devices. Today's electronic devices will usually present a electrical connector (e.g. USB) through which 'raw data'' can be streamed into a personal computer.