The correct option is 'Deletion or Removal'. The DeleteOnSubmit method in LINQ to SQL is used to mark an entity for deletion. It does not immediately delete the entity from the database but rather flags it for deletion. The actual deletion occurs when the SubmitChanges method is called on the DataContext. This method is commonly used to prepare objects for deletion before committing changes to the database.

When optimizing database table mappings in Entity Framework for better performance, it's essential to avoid over-fetching data by projecting only the required columns in queries. This reduces network overhead and improves query execution time. Additionally, using eager loading instead of lazy loading can help fetch related entities upfront, reducing the number of subsequent database calls. Implementing proper indexing on frequently queried columns enhances query performance by facilitating faster data retrieval. Minimizing round trips to the database by batching multiple operations into a single transaction reduces latency and improves overall throughput. These considerations help optimize the performance of Entity Framework applications by efficiently managing database interactions.

When dealing with Entity Framework performance, it's important to consider the "SQL Queries" of database queries generated by the mappings. Entity Framework translates LINQ queries into SQL queries to interact with the database. Understanding and optimizing the SQL queries generated by Entity Framework can significantly improve the performance of your application.

In Entity Framework, the ApplyCurrentValues method allows you to specify custom logic to resolve concurrency conflicts. This method is typically used when you need to apply changes from a detached entity to the context.

To retrieve order details for a specific customer's orders using DataRelations, you would use the GetChildRows method to obtain the child rows related to the customer's orders. This method allows accessing the related child rows based on the specified parent row. The GetParentRow method is used to retrieve the parent row from a child row. Setting the Nested property to true enables navigating through hierarchical data. Setting the RelationName property to "OrderDetails" specifies the relation to use for retrieving order details. This approach leverages the hierarchical structure defined by DataRelations to efficiently access related data.

In ADO.NET, parameters are passed to a stored procedure using SqlParameter objects. These objects allow for type-safe and secure parameter passing, helping prevent SQL injection attacks and ensuring correct data types.

The SqlConnection class in ADO.NET is responsible for managing database connections efficiently. It represents a connection to a SQL Server database and provides methods for opening, closing, and managing transactions on the connection. SqlConnection is essential for establishing a connection to a database server and executing commands against it. It also handles connection pooling internally, which helps in optimizing connection usage and improving performance by reusing existing connections instead of creating new ones for each database operation. Understanding how to effectively work with SqlConnection is fundamental for building scalable and efficient database-driven applications in .NET.

GridView control is commonly used for displaying and editing tabular data in ASP.NET applications. It offers powerful data-binding capabilities, allowing developers to easily bind data from various data sources and display it in a tabular format. It also supports features like sorting, paging, and editing, making it a preferred choice for working with tabular data.

The correct option is OracleCommand. When working with Oracle databases in .NET applications, the OracleCommand class is specifically designed to execute commands against an Oracle database. It provides methods and properties to facilitate database interactions, making it the appropriate choice as a command object for Oracle databases.

Query optimization in LINQ involves techniques such as using appropriate indexes, selecting only necessary columns, and minimizing data transfer between the database and application to improve performance. It aims to eliminate unnecessary data retrieval and processing, thus enhancing query efficiency.