Scenario: You have two collections of objects, orders and customers, and you need to retrieve a list of orders along with their corresponding customer information. Which LINQ operator would you use for this task?
- Join
- Select
- GroupJoin
- Concat
The correct option is Join. The Join operator is used to combine two collections based on a related key and select the result into a new collection. In this scenario, you would use Join to combine the orders and customers collections based on a common key, such as CustomerID, to retrieve a list of orders along with their corresponding customer information.
The ExecuteNonQuery method of a command object is typically used for executing _______ SQL commands.
- Insert
- Non-Query
- Select
- Update
The ExecuteNonQuery method is used to execute SQL commands that do not return data, such as INSERT, UPDATE, DELETE, or any SQL command that does not return a result set. It is commonly used for executing data manipulation language (DML) statements.
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.
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.