What are some common list controls used in ADO.NET for data binding purposes?

  • ListBox
  • DropDownList
  • ComboBox
  • RadioButtonList
In ADO.NET, common list controls used for data binding include ListBox, DropDownList, ComboBox, and RadioButtonList. These controls facilitate displaying data retrieved from a data source, providing users with options to select or interact with the data displayed. DropDownList, specifically, is commonly used for displaying a list of items where users can select one option.

Your application involves updating records across different databases. How would you implement distributed transaction management in ADO.NET?

  • Data Reader
  • OleDbConnection
  • SqlCommand
  • TransactionScope
Distributed transaction management in ADO.NET can be implemented using TransactionScope. TransactionScope provides a simple and efficient way to manage distributed transactions across multiple databases or resource managers. It automatically handles enlisting connections in the transaction and ensures that either all operations across different databases succeed or fail together, maintaining data integrity and consistency.

Scenario: You are developing a WinForms application that needs to display a list of products from a database. Which control and data binding method would you use to achieve this?

  • DataGridView with DataSource property
  • ListBox with DataBinding event
  • ComboBox with DisplayMember property
  • DataGrid with Bind method
The correct option is DataGridView with DataSource property. DataGridView is a versatile control for displaying tabular data and supports data binding through its DataSource property, which allows you to easily bind it to a data source such as a DataTable or a list of objects. This control provides rich functionality for displaying and editing data in a grid format, making it suitable for displaying a list of products from a database.

Which event is triggered when a user selects a row in a DataGrid or DataGridView control?

  • CellValueChanged
  • RowEnter
  • RowHeaderMouseClick
  • RowSelected
The "RowEnter" event is triggered when a user selects a row in a DataGrid or DataGridView control. This event occurs when the focus moves to a new row, indicating that the user has selected that row. It provides an opportunity to perform actions based on the selected row, such as retrieving data or updating other controls.

What happens to the data reader when you close the associated database connection?

  • The data reader becomes null
  • The data reader is disposed automatically
  • The data reader remains open
  • The data reader throws an exception
When you close the associated database connection, the data reader throws an exception. This is because the data reader relies on the connection to fetch data from the database. Closing the connection while the data reader is still in use results in an exception being thrown to indicate the invalid operation. It's essential to close the data reader before closing the connection to avoid this issue.

You have a complex inheritance hierarchy in your entity model. How can Entity Framework help you map these entities to the appropriate database tables?

  • Entity Splitting
  • Table-per-Concrete-Type (TPC)
  • Table-per-Hierarchy (TPH)
  • Table-per-Type (TPT)
Entity Framework provides support for mapping complex inheritance hierarchies to database tables using Table-per-Hierarchy (TPH) strategy. In TPH mapping, all classes in the inheritance hierarchy are mapped to a single database table, with a discriminator column used to differentiate between different types of entities. This approach simplifies the database schema by reducing the number of tables required to represent the inheritance hierarchy, making it easier to manage and query related entities.

To navigate through hierarchical data, you can use the ___________ property of a DataRow.

  • ChildRows
  • GetChildRows()
  • GetParentRow()
  • ParentRow
The ChildRows property of a DataRow allows you to access all the child rows related to the current DataRow through the specified DataRelation. This is particularly useful when working with hierarchical data structures in ADO.NET.

In a SELECT statement, what keyword is used to specify which columns to retrieve from a table?

  • FROM
  • INTO
  • SELECT
  • WHERE
In a SELECT statement, the "SELECT" keyword is used to specify which columns to retrieve from a table. It is followed by the column names or expressions that you want to retrieve data from.

When should you use parameterized queries instead of plain SQL statements?

  • When dealing with static data retrieval
  • When executing complex joins
  • When handling database schema modifications
  • When performing queries involving user input
Parameterized queries should be used when performing queries involving user input to prevent SQL injection attacks. By using parameterized queries, input values are treated as data rather than executable code, making it much harder for attackers to inject malicious SQL code into the query. This helps enhance security and protect the database from unauthorized access.

The _________ property of a SqlParameter determines whether a parameter is an input or output parameter.

  • Direction
  • Name
  • Type
  • Value
In ADO.NET, the Direction property of a SqlParameter object determines whether the parameter is an input parameter, an output parameter, or both. This property is crucial for specifying the role of the parameter in the stored procedure.