9 Common ADO.NET Interview Questions (With Example Answers)

Updated 30 September 2022

ADO.NET is a piece of software that stores, protects and regulates access to pools of digital data. This system makes it possible to transfer data between relational and non-relational databases, modifying it to suit the structures of each database. If you are planning a career in software engineering, you can benefit from knowing more about some common questions interviewers ask about ADO.NET. In this article, we explain the purpose of ADO.NET interview questions, discuss how to answer them and share nine examples of questions and their answers.

Purpose Of ADO.NET Interview Questions

Interviewers can ask you ADO.NET interview questions to test your knowledge of this piece of software. If you are applying for a job as a data analyst, it is advisable that you prepare your answers for these types of questions. In an interview, you might initially answer more basic questions, covering simple facts and terms related to this software. These queries can become more complex as the interview continues, shifting focus to how you could use ADO.NET to complete practical tasks.

9 examples Of ADO.NET Interview Questions

If you are invited to an interview to discuss ADO.NET, you could find it useful to revise your knowledge of the software beforehand. In the discussion, interviewers can ask both practical and technical questions, designed to test your overall knowledge of the software. These questions may discuss varied topics, such as definitions or more niche practical tasks. Here are nine examples of interview questions on ADO.NET:

1. How do relational and non-relational databases differ?

At the beginning of an interview, the interviewer might first test your knowledge of basic concepts that relate to this software. By specifically asking about differences between relational and non-relational databases, the interviewer can determine whether you can use the software effectively in a professional context. In your response, clearly state the differences between these types of databases before relating them to ADO.NET.

Example: 'Relational databases are more traditionally formatted, storing data in rows and columns similar to a traditional spreadsheet. Non-relational databases are more customisable, using the storage system best suited to the type of data involved. They can also store unlimited quantities of data, whereas relational systems are well-suited to handling data related to a specific project. By using ADO.NET, you could transfer data from one system to the other, altering its format to suit your organisation's purposes.'

2. What are DataSets?

By asking this type of question, the interviewer hopes to test your knowledge of basic concepts related to the ADO.NET software. In response, it is useful to clearly define the term 'DataSets' before briefly detailing their practical uses.

Example: 'In ADO.NET, DataSets are groups of rows and columns that contain information. By using this tool, you could access data without interacting with the data source itself. Each DataSet includes a DataTable, made up of a selection of rows and columns. The pieces of data contained within these rows and columns often relate to each other in some way. DataSets usually include one or several examples of a DataRelation. These elements connect one DataTable to another through shared or related data, making it easier to navigate between data sets.'

3. What elements make up the ADO.NET system?

Like the previous question, this question might test your technical understanding of ADO.NET to judge if you could effectively source data in a professional context. In response, you can outline the three elements that make up this system, alongside their respective functions.

Example: 'ADO.NET is made up of three distinct modes, referred to as the disconnected, shared and .NET data provider modes. When combined, you can use these modes to transfer important data between different databases. The disconnected mode provides the digital structures that you use to perform the data transfer. In contrast, the shared mode provides the base classes for grouping data, from which any related sub-classes stem. The .NET data provider regulates data access services, such as programming commands or sourcing data from its original location.'

4. How do the shared and connected modes differ?

Like the previous question, this question might test your technical understanding of ADO.NET, to judge if you could effectively source data in a professional context. In response, you could outline the comparative use of the shared and connected modes for data transference.

Example: "Depending on your purposes, you can benefit from using either the shared or connected mode to transfer data. By using the former mode, you can transfer data more quickly, as it allows you to read data, rather than annotate it. This mode also offers faster transfer speeds, as it can only manage data from a single table. In contrast, by using the disconnected mode, you could transfer large quantities of data and edit it later, though ADO.NET may take longer to transfer data as a result."

5. What elements make up the data provider?

Like the previous question, this question might test your technical understanding of ADO.NET, to judge if you could use the software for work purposes. In response, you may outline the four distinct elements that form the data provider, before detailing their respective purposes.

Example: "Four elements make up a data provider: the Connection, Command, DataReader and DataAdapter. The first element connects to the initial data source so that you may transfer data from its location to a new place of storage. The Command element submits a SQL query to ask for permission to transfer data to this location. The DataReader then links to the Connection, aiding data transference by building a connection between it and the data set. After transferring data, you can use the DataAdaptor to view, change or remove data in its new location."

6. What are the advantages of using ADO.NET to transfer data?

By asking this question, the interviewer aims to test whether you recognise the productivity benefits of using ADO.NET to source data. In response, it is advisable to detail at least two benefits of this software, preferably by relating them to work activities.

Example: "There are many advantages of using ADO.NET to source or transfer data. For example, you can scale up this system to suit your organisation's requirements. You may use this system to work with various associates at the same time, without facing reduced speed or performance. ADO.NET can also boost general productivity, as you can use the vast quantities of data sourced to develop high-quality and intuitive digital products, such as software or mobile apps."

7. How does Connection Pooling work?

In the latter stages of an interview, the interviewer could ask questions about more niche technical aspects of ADO.NET. By discussing Connection Pooling, the interviewer intends to assess if you recognise the productivity benefits of this process. In response, you may briefly define this concept before explaining how it works in practice.

Example: "Connection Pooling involves sharing your connection with others so that multiple users may access the data pool. This process reuses active connections with an identical connection string to reduce the time that you might spend opening or closing new connections. By using Connection Pooling, you can avoid creating a new connection each time that colleagues request access to a data set. A Connection Manager monitors existing connections by keeping a list of links, permitting access to data sets on request. By using this system, you can then share data with colleagues more easily, boosting general productivity."

8. What is the significance of a SqlCommand Object?

By asking this question, the interviewer hopes to learn whether you know how to locate, alter or extract data from a database via ADO.NET. In response, you could define SQLCommand Object, before detailing three ways of using this process to access a database.

Example: "The SQLCommand Object performs the command that you might issue via a SQL query or carry out a stored procedure. You can use several methods to acquire data using a SQLCommand Object. For example, you can use the ExecuteNonQuery command to carry out DML Statements. You can then manipulate the data in varied ways, such as by adding, deleting or merging rows. Conversely, you can use the ExecuteReader command, through which you can source specific rows or columns of information. A third option is the ExecuteScalar command, which you can use to source specific values from a database."

9. How do Parameters work in ADO.NET?

By asking this question, the interviewer hopes to learn whether you fully understand more niche elements of ADO.NET. In response, you can briefly explain what parameters are, before outlining several properties that influence the scope of this function.

Example: "Parameters are rules for carrying out an SQL query or a stored procedure, using specific values to source the correct data each time. Parameters often have varying properties, each defining a specific aspect or function. For example, the ParameterName property details the rule's title, providing a basic description of its purpose. The Value property reflects the numerical value of this rule. The Precision property reflects the numbers within the value, whereas the Scale reflects the number of decimal places within this figure."