Introduction to ADO.NET Interview Questions and Answers
ADO.NET is a module or set of classes which provides data access services from managed languages to Microsoft .NET framework. ADO.NET provides a complete set of libraries for data access and its strength is that it allows applications to collect or access different forms of data using the same methodology. Suppose if we know how to access Oracle from ADO.NET, we can use the same methodology to access data from SQL, MySQL and other databases using a set of libraries and classes provided by ADO.NET. It is an internal part of Microsoft .NET framework which allows access to XML, relational, different types of applications data. It acts as a bridge between applications and databases to access and manage data. ADO.NET is widely used for data accessing, selecting, deleting, saving and other data management operations. ADO.NET is an active database object, which has inbuilt automatic driver detection technique provides to a connected environment which may decrease the efficiency. As ADO.NET is extensively used with a .NET framework for data management, cracking the interview requires basic skills and experience.
Now, if you are looking for a job which is related to ADO.NET then you need to prepare for the 2019 ADO.NET Interview Questions. It is true that every interview is different as per the different job profiles but still to clear the interview you need to have a good and clear knowledge of ADO.NET. Here, we have prepared the important ADO.NET Interview Questions and Answers which will help you get success in your interview.
In this 2019 ADO.NET Interview Questions article, we shall present 10 most important and frequently used ADO.NET interview questions. These questions will help students build their concepts around ADO.NET and help them ace the interview.
Part 1 – ADO.NET Interview Questions (Basic)
This first part covers basic ADO.NET Interview Questions and Answers
Q1. In which namespace .NET has data functionality class?
ADO.NET has provided the following namespaces for data management as below:
- Data.OleDB – It has the object need to connect to a data source via OLE-DB which will inherit from common base classes which will have the same properties, methods, and events.
- Data.SqlClient – It has the object need to connect to the data source via TDS which is an interface of Microsoft SQL Server and it provides better performance than OLE_DB as SqlClient removes some intermediate layers required by the OLE-DB connection.
- Data – It has the objects need to use for accessing, storing relational data from Dataset, Data tables, and Relations which are independent of data source type and method to connect to data source.
- XML – It has objects needed to create, read, write, store, and manipulate XML documents according to W3C.
- Data.OracleClient – It contains objects/classes such as Oracle command, OracleConnection which are required to connect to Oracle Database.
Q2. What is the difference between Dataset and DataReader?
This is the basic ADO.NET Interview Questions asked in an interview. The difference between Dataset and DataReader as below:
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- DataSet – Dataset is an object which is a disconnected architecture which can persist the contents of a table and can hold more than one table from the same data source.
- DataReader – DataReader is an object which is a connected architecture which can’t persist content of a table as it provides forward-only and read-only access to data.
Q3. What is the use of connection object?
The use of the connection object is to connect data to a command object. Different connection objects are used to different providers such as an OleDbConnection object for OLE-DB provider and SqlConnection object for Microsoft SQL server.
Let us move to the next ADO.NET Interview Questions.
Q4. What is the Difference between Data Grid and Data Repeater?
The difference between Data Grid and Data Repeater is as below:
- Data Grid – Data Grid provides many features and functionality to users to perform paging, sort the data in table easily. It can hold the text object data but it can’t hold embedded or linked objects data.
- Data Repeater – Data Repeater has offered so many features which are not offered by Data Grid such as – It can hold the control of embedded and linked objects data and it can embed Data Grid in it but vice-versa is not possible. It doesn’t have support for Paging functionality but can be achieved by programming it.
Q5. What are the important features of ADO.NET 2.0 version?
The important features of ADO.NET 2.0 version as below:
- Batch Update: Batch update means it will update n number of rows of a table in a single call from a program.
- Data Paging: Data paging provides an easy way to read data from a given index from the database table.
- Bulk Copy Operation: It provides the facility of a bulk copy of data from one data source to another data source easily.
- Connection details: It provides details about connections like the cursor, buffer, and storage object etc. information.
- DataTable’s Load and Save methods: It is used for XML data interactions, storing, writing, and manipulating XML data based on W3C standards and it provides dataset serialization in binary using dataset removing format Property.
Part 2 – ADO.NET Interview Questions (Advanced)
Let us now have a look at the advanced ADO.NET Interview Questions.
Q6. What is connection pooling in ADO.NET?
Connection pooling is the ability to re-use connections to the database i.e. if we mention/enable connection pooling in the connection object it means we enabled re-use of that connection to more than one user. It reduces the cost of repeatedly connection opening and closing which uses the connection manager which maintains the list of connections, pool, and available connections.
Following are some of the pooling attributes of SQL Server connection as below:
- Connection Lifetime: It describes the lifetime of the connection from a time of the creation to the closing time of the connection.
- Load balance timeout: It describes that how much time can a connection remain idle in the connection pool.
- Max pool size, Min Pool size etc.
Q7. What is the difference between classic ADO and new ADO.NET?
This is the advanced ADO.NET Interview Questions asked in an interview. The major differences between classic ADO and ADO.NET as below:
- ADO has Recordset whereas ADO.NET has DataSet
- In Recordset if we want to have more table data we need to perform inner join whereas DataSet can have multiple table data.
Q8. What is the use of the Data Adapter?
Data Adapter objects connect one or more command objects to the DataSet object. Data Adapter objects provide logic for getting data, storing it and populates the tables in the dataset object.
Let us move to the next ADO.NET Interview Questions.
Q9.What is the SqlCommandBuilder?
SqlCommandBuilder helps users to generate an update, insert, and delete commands on a single table for a data adapter. Each Data adapter object has a command builder class. Some of the examples of CommandBuilder classes as below:
An OleDbCommandBuilder, SqlCommoandBuilder, and OdbcCommandBuilder class represents OleDb, SQL, and ODBC data providers.
Q10. Explain the ExecuteScalar method in ADO.NET?
The ExecuteScalar Method in SqlCommand Object returns the first column of the first row after executing the query against a data source. If the result set is empty, it will ignore the result set. If the result set having more than one column or one row it will take the only first column of the first row only, remaining values are ignored.
This has been a guide to list Of ADO.NET Interview Questions and Answers so that the candidate can crackdown these ADO.NET Interview Questions easily. Here in this post, we have studied top ADO.NET Interview Questions which are often asked in interviews. You may also look at the following articles to learn more –