Hiring guide for Transact-SQL Function (TSQL Function) Engineers

Transact-SQL Function (TSQL Function) Developer Hiring Guide

Transact-SQL Function, also known as TSQL Function, is a proprietary procedural language developed by Microsoft for interacting with relational databases. Introduced in 1987, it was initially created to augment the capabilities of SQL, adding procedural programming and local variable functions. The TSQL Function is primarily used in SQL Server, Microsoft's flagship database management system. This language is integral in executing a wide range of tasks such as querying data, modifying data, and implementing error handling. Its robust functionality and versatility have made it an indispensable tool in the field of database management.

Ask the right questions secure the right Transact-SQL Function (TSQL Function) talent among an increasingly shrinking pool of talent.

First 20 minutes

General Transact-SQL Function (TSQL Function) app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Transact-SQL Function (TSQL Function) application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

What are the different types of TSQL functions?
There are three types of TSQL functions: scalar functions, inline table-valued functions, and multi-statement table-valued functions.
How would you use a scalar function in TSQL?
A scalar function in TSQL can be used by calling the function by its name and passing the required parameters. The function then returns a single value.
Describe the difference between a stored procedure and a function in TSQL.
The main difference is that a function must return a value, but a stored procedure doesn't have to. Also, functions can be used in a SELECT statement, while stored procedures cannot.
What is the purpose of the RETURN statement in a TSQL function?
The RETURN statement is used to end the execution of the function and return the result to the caller.
How would you handle errors in a TSQL function?
Errors in a TSQL function can be handled using the TRY...CATCH construct. The code that might cause an error is placed in the TRY block, and the error handling code is placed in the CATCH block.
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What you’re looking for early on

Does the candidate demonstrate a strong understanding of TSQL Function?
Can the candidate communicate effectively about technical concepts?
Has the candidate shown problem-solving skills during the interview?
Does the candidate have experience with database design and data modeling?

Next 20 minutes

Specific Transact-SQL Function (TSQL Function) development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

What are the limitations of using a function in TSQL?
Functions in TSQL cannot modify database state, cannot include dynamic SQL or temporary tables, and cannot call a procedure.
How would you use a table-valued function in a SELECT statement?
A table-valued function can be used in the FROM clause of a SELECT statement, just like a regular table.
What is the difference between an inline table-valued function and a multi-statement table-valued function?
An inline table-valued function returns the result of a single SELECT statement, while a multi-statement table-valued function can contain multiple statements and returns a table variable.
How would you optimize a TSQL function for performance?
Performance can be optimized by reducing the amount of data processed, using set-based operations instead of cursors or loops, and by using indexes effectively.
What is the impact of a function on the execution plan in TSQL?
A function can affect the execution plan by adding additional operations, which can potentially slow down the query. The impact depends on the complexity of the function.
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The ideal back-end app developer

What you’re looking to see on the Transact-SQL Function (TSQL Function) engineer at this point.

At this point, a skilled Transact-SQL Function (TSQL Function) engineer should demonstrate strong problem-solving abilities, proficiency in Transact-SQL Function (TSQL Function) programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Transact-SQL Function (TSQL Function).

What does the following T-SQL function do?
CREATE FUNCTION dbo.GetEmployeeCount() RETURNS INT AS BEGIN RETURN (SELECT COUNT(*) FROM Employee) END
This function returns the total number of records in the Employee table.
What will be the output of the following T-SQL function?
CREATE FUNCTION dbo.GetEmployeeName(@EmpId INT) RETURNS VARCHAR(100) AS BEGIN RETURN (SELECT Name FROM Employee WHERE Id = @EmpId) END
This function returns the name of the employee whose Id is passed as a parameter to the function.
What does the following T-SQL function do?
CREATE FUNCTION dbo.GetEmployeeNames(@DeptId INT) RETURNS TABLE AS RETURN (SELECT Name FROM Employee WHERE DeptId = @DeptId)
This function returns a table containing the names of all employees in the department whose Id is passed as a parameter to the function.
What will be the output of the following T-SQL function?
CREATE FUNCTION dbo.GetEmployeeSalary(@EmpId INT) RETURNS MONEY WITH SCHEMABINDING AS BEGIN RETURN (SELECT Salary FROM Employee WHERE Id = @EmpId) END
This function returns the salary of the employee whose Id is passed as a parameter to the function. The SCHEMABINDING option ensures that the underlying table structure cannot be modified while this function exists.

Wrap-up questions

Final candidate for Transact-SQL Function (TSQL Function) Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Transact-SQL Function (TSQL Function) application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you debug a TSQL function?
You can debug a TSQL function using the SQL Server Management Studio debugger. You can set breakpoints, step through the code, and inspect variables.
What is the difference between deterministic and non-deterministic functions in TSQL?
A deterministic function always returns the same result for the same input, while a non-deterministic function can return different results each time it is called with the same input.
How would you use a function in a CHECK constraint in TSQL?
A function can be used in a CHECK constraint to validate the data before it is inserted or updated. The function should return a boolean value indicating whether the data is valid.

Transact-SQL Function (TSQL Function) application related

Product Perfect's Transact-SQL Function (TSQL Function) development capabilities

Beyond hiring for your Transact-SQL Function (TSQL Function) engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Transact-SQL Function (TSQL Function) projects, and can engage in multiple capacities.