Are you looking for a job as a SQL Developer? Or are you thinking of leaving your current position for a new job in SQL development environment with a new company?
If you answered “Yes” to either of those questions, then this article is a must read for you. Any of the described technologies and questions might be asked of you during the interview!
The demand for SQL developers is continuously growing because of the rapid increase in the number of websites and software applications with integrated data warehouses. A candidate having high-end SQL development skills with advanced technical education and excellent communication is always in demand of top companies.
An Introduction with SQL Developer Roles and Responsibilities
SQL developers are responsible for developing, analyzing, and support applications that integrate with the SQL (aka “sequel”) database computer language. An SQL developer’s job also involves creating tables, progressive reporting and other functions, such as stored procedures, clustering and recover/update a database. They are also responsible for code documentation, reports generation and report review.
The SQL Developer responsibilities:
Development and optimization of SQL database and applications (that interface with SQL databases)
Code testing (of designing tables, storing procedures, views and functions, etc.)
Care Database integrity, security, availability and performance
Creation of SQL database prototypes (to validate system requirements)
Report development services
Quality checks on progressive reporting
Recovery, backup, and updating of SQL databases
Electronic data interfaces (EDI) management with various vendors
Monitor query execution and transfer queues to ensure proper functionality
Provide business data required for metrics and analysis
Development of new SSIS/SSRS packages and migration of existing Access reports to SSIS/SSRS packages
Creation and maintenance of project documentations
Managing multiple projects with deadlines
My Best Questions for an Interview of an SQL Developer: All of the questions below are very common and must be well prepared for before facing any interview for the developer position in SQL environment. Be honest and confident while answering.
Most of interviews for SQL Developer positions start with following common questions such as:
“Tell me something about yourself.”
“Questions related to current/previous job roles.”
“What are your major strengths and weaknesses?”
“How do you find your qualification and experience as a SQL developer?”
“Share some of your achievements as a database professional?”
“What is your salary expectation for this position?”
While answering about your current/previous job role, don’t forget to mention your responsibilities with recent activities and achievements. Apart from above HR/ Personal questions, let’s discuss some important technical questions as well.
Q. How do you define the term “database”?
A. Database provides a single-point mechanism for storing and retrieving information with the help of tables. These tables are made up of columns and rows, where each column stores specific attribute and each row displays a value for the corresponding attribute.
Q. What is the purpose of cluster in a database?
A. Cluster is used for storing table data. It contains group of tables that share the same data blocks. Clusters can’t be used for the frequently fetched tables.
Q. Define RAID and its different levels?
A. RAID (redundant array of inexpensive/independent disks) is a data storage virtualization technology. Using RAID, multiple physical disk drives act as a single logical unit to improve data redundancy and performance. RAID levels are referred to data distribution across the multi-drives. To know more about RAID levels visit the following link https://en.wikipedia.org/wiki/Standard_RAID_levels.
Q. What is the role of candidate key in a database?
A. A candidate key is a column or set of columns in a table that can uniquely identify any database record. A table can have one or more candidate keys, and one of the candidate keys is also considered as the primary key. To know more about the functional behavior of a candidate key visit this link:
Q. When do we use HAVING and WHERE clause?
A. This is one of the most common questions asked during the database development positions and must be prepared for before facing the interview. Here’s how you can describe the difference between the WHERE and HAVING clauses: the WHERE clause can be applied only on a stati,c non-aggregated column whereas we have to use HAVING with aggregated columns. Let’s analyze more differences:
The WHERE clause can be implemented without the GROUP BY clause; but, while implementing the HAVING clause, the GROUP BY clause is mandatory.
The WHERE clause selects rows before grouping and the HAVING clause selects after grouping.
Q. What is the significance of the “UPDATE_STATISTICS” command?
A. UPDATE_STATISTICS command is essential when a large processing of data has occurred; this command is used to update query optimization statistics on a table or indexed view.
Q. What do you mean by normalization? Explain the functionalities of normalization.
A. “Normalization” is used to minimize redundancy and dependency of a relational database by organizing the fields and tables that saves storage space and ensures consistency of our data.
There are six different normal forms
• First Normal Form – If all underlying domains contain atomic values only.
• Second Normal Form – If it is in first normal form and every non-key attribute is fully functionally dependent on primary key.
• Third Normal Form – If it is in second normal form and every non-key attribute is non-transitively dependent on the primary key.
• Boyce Codd Normal Form – A relation R is in BCNF if and only if every determinant is a candidate key.
• Fourth Normal Form – Multivalued dependency.
• Fifth Normal Form – Join dependency.
Q. What is the difference between primary-key and unique-key?
A. A Primary key is used for unique identification of records in a relational database and a table must have only one primary key. A primary key column never allows NULL values, and modification or delete values cannot be performed. A unique key prevents duplicate values in a column; a table can have multiple unique keys. A unique key column can have null value and its entries can be edited or removed.
Q. What do you mean by stored procedures and is it possible for a stored procedure to call itself?
A. A stored procedure is a group of SQL statements with an assigned name that’s stored in the compiled form so it can be reused over and over again. Yes, a stored procedure can call itself and this recursive behavior is known as stored procedure nesting.
Q. What are the advantages of creating a view in SQL database?
A. A view can be described as virtual table or a stored query, and defining views in a database can improve performance by hiding the complexity of data and providing better space utilization; since views do not consume large amounts of space, it joins multiple tables into a single virtual table. The following link will provide further details on it: https://en.wikipedia.org/wiki/View_(SQL).
Q. What will happen if we execute the DELETE and TRUNCATE commands?
A. The delete command is used to delete data from a table, whereas the truncate command is extremely risky and must be used carefully, as it deletes every single row from a table. The syntax of this command is as follows:
TRUNCATE TABLE “table_name”
Q. Name some of reporting mechanism. Explain the difference between drill-down and drill-through reporting?
A. There are various reporting services that enable you to create the following types of reports:
•Ad hoc reports
A drill-down reporting service hides complexity and provides conditional report items to regulate how much data detail you want to see, while a drill-through reporting service provides a separate report that has its own layout, data sources, parameters and datasets. Refer to the following link to learn more about drill-through reporting services: https://msdn.microsoft.com/en-us/library/dd207031.aspx.
Q. Why do we use an execution plan? Explain the advantages of using one.
A. The execution plan feature is used for the explicit display of data retrieval techniques preferred by the SQL Server query optimizer and it uses icons to represent the execution of specific statements and queries in SQL Server rather than the tabular representation produced by the T-SQL SET statement or the XML for representation produced by SET SHOWPLAN_XML. To know more about execution plans, use the following link:
The questions above are very collective and important from the standpoint of clearing an interview of SQL developer positions. I have tried to explain most of my best possible set of questions. You can also get more frequently asked interview questions for SQL developer’s jobs from the download link posted here. If you find any difficulty in answering any of question, then you can write me @ Comment section.
Before facing any Interview, a candidate should take care of following points;
A quick recap of relevant technologies.
Read your resume through and make sure you have detailed your strength/weaknesses, achievements and prior job roles and responsibilities.
Professional certifications allow the interviewer to understand your knowledge level, so point your certifications (if you have any).
An updated LinkedIn profile helps you a lot to get job recommendations and referrals for your desired job roles.
This article is the output of my extensive research and work experience, and my team, corporate clients, and colleagues helped me a lot to develop this article. With this article I am trying to help/guide candidates about interview preparation for getting SQL developer or management position in the field of SQL environment.
I hope this article will be appreciated so that I will be able to offer more in this segment. You can write me @comment section below to provide any query/feedback; I will do my best to resolve your queries at the earliest. And don’t forget to spread the link of this article on your Facebook, Twitter, and LinkedIn accounts so the maximum number of people can get this exclusive piece of information. Keep reading @ Intensechool.com and consider joining our Facebook group, http://www.facebook.com/intenseschool, to get updates on new posts and technologies.