20 Stored Procedure Interview Questions and Answers

Stored procedures are an important part of any database-driven application. They can help improve performance by reducing the amount of data that needs to be retrieved from the database. When interviewing for a position that involves working with stored procedures, it is important to be prepared to answer questions about your experience and knowledge. In this article, we will review some common stored procedure interview questions and provide some tips on how to answer them.

Stored Procedure Interview Questions and Answers

Here are 20 commonly asked Stored Procedure interview questions and answers to prepare you for your interview:

1. What are Stored Procedures?

A stored procedure is a set of SQL commands that are stored in a database. They are typically used to perform a specific task or function. Stored procedures can be used to improve performance by reducing the amount of SQL code that needs to be executed. They can also be used to enforce security by controlling who has access to the stored procedure and what they are allowed to do with it.

2. Can you explain the benefits of using stored procedures in a database?

There are several benefits to using stored procedures in a database, including:

1. Increased security: Stored procedures can help to increase security by restricting access to sensitive data and by providing a layer of abstraction between the data and the users.

2. Increased performance: Stored procedures can improve performance by reducing the amount of data that needs to be transferred between the database and the application.

3. Reduced development time: Stored procedures can save development time by allowing developers to reuse code.

4. Improved maintainability: Stored procedures can improve maintainability by allowing changes to be made in one place and propagated to all applications that use the stored procedure.

3. How do you create a stored procedure in SQL Server?

There are a few different ways to create a stored procedure in SQL Server. One way is to use the “CREATE PROCEDURE” statement. Another way is to use the “sp_create_procedure” system stored procedure.

4. How can you update information in a table using a stored procedure?

You can update information in a table using a stored procedure by using the UPDATE statement. The UPDATE statement will allow you to modify the data in a table and then save those changes back to the table.

5. What’s the difference between executing a query and calling a stored procedure?

When you execute a query, the database engine looks for the best way to execute the query based on the available resources and optimizes the query accordingly. A stored procedure is a set of pre-compiled SQL statements that are stored in the database. When you call a stored procedure, the database engine executes the stored procedure directly.

6. Is it possible to have multiple statements inside a stored procedure? If yes, then how?

Yes, it is possible to have multiple statements inside a stored procedure. You can do this by using the BEGIN and END keywords to enclose the multiple statements inside the stored procedure.

7. What is an input parameter for a stored procedure and how do you specify one?

An input parameter is a value that is passed into a stored procedure when it is executed. You specify an input parameter by including it in the list of parameters when you create the stored procedure.

8. Can you explain what an output parameter is used for in a stored procedure?

An output parameter is a parameter that is used to return a value from a stored procedure back to the caller. Output parameters are declared by using the OUTPUT keyword when the parameter is created. When the stored procedure is executed, the output parameter will contain the value that was assigned to it by the stored procedure.

9. In case of stored procedures with input parameters, is there a way to assign default values to them if they’re not passed while execution?

Yes, there is a way to assign default values to input parameters in stored procedures. This can be done by using the DEFAULT keyword when defining the parameters. For example:

CREATE PROCEDURE myproc (IN param1 INT DEFAULT 0, IN param2 VARCHAR(255) DEFAULT ‘abc’)

If param1 and param2 are not passed in when the stored procedure is executed, then they will take on the default values of 0 and ‘abc’, respectively.

10. Can you give me some examples of real-world use cases where stored procedures would be useful?

Stored procedures can be used for a number of different things, but they are most commonly used for tasks that need to be performed regularly, or tasks that need to be performed by multiple people. For example, if you have a task that needs to be performed every day, you can create a stored procedure to automate it. Or, if you have a task that needs to be performed by multiple people, you can create a stored procedure and give each person their own copy. This way, everyone has the same instructions and can perform the task correctly.

11. What happens when you try to execute a nested stored procedure (one that executes another)?

When you try to execute a nested stored procedure, the inner stored procedure will be executed first. This can cause problems if the inner stored procedure is not designed to be executed on its own.

12. How do you call a stored procedure from within another stored procedure?

You can call a stored procedure from within another stored procedure by using the sp_executesql system stored procedure.

13. What is the best way to return data from a stored procedure?

The best way to return data from a stored procedure is to use a result set. This will allow you to return multiple rows of data from the stored procedure.

14. Can you explain what cursors are and why should we avoid using them in stored procedures?

Cursors are basically pointers that allow you to iterate through a result set one row at a time. They can be useful in some situations, but in general they are best avoided in stored procedures because they can be quite slow and can cause performance issues.

15. Why do you think stored procedures don’t support exception handling like other programming languages?

The main reason why stored procedures don’t support exception handling is because they are designed to be executed as a unit, and not as individual statements. This means that if one statement in a stored procedure fails, then the entire procedure will fail. This can be seen as a disadvantage, but it also ensures that all of the statements in a stored procedure are executed in the correct order.

16. What does the “CREATE PROCEDURE” statement mean in context of stored procedures?

The CREATE PROCEDURE statement is used to create a new stored procedure. This statement defines the name and parameters of the stored procedure, as well as the code that will be executed when the procedure is called.

17. Can you explain what a stored procedure template is?

A stored procedure template is a type of stored procedure that can be used as a starting point for creating new stored procedures. A stored procedure template can contain placeholder values that can be replaced with actual values when the stored procedure is created. This can be helpful in creating stored procedures that are similar to each other, but with different values.

18. Can you tell me some system functions available in SQL Server?

There are a number of system functions available in SQL Server, including:

– LEN: Returns the length of a given string
– DATENAME: Returns the name of a given date
– GETDATE: Returns the current date and time
– ISNULL: Checks whether a given value is NULL
– CASE: Evaluates a list of conditions and returns one of multiple possible results

19. What does @name stand for in the context of stored procedures in SQL Server?

@name is a parameter in a stored procedure. It is used to pass a value into the stored procedure.

20. Are there any limitations on using stored procedures? If yes, then please elaborate.

Yes, there are some limitations on using stored procedures. One such limitation is that they can be difficult to debug because they are not written in a high-level language like most other code. Additionally, stored procedures can be difficult to maintain because they are often tightly coupled to the database schema.