In LINQ to DataSet, what is the primary purpose of the from clause?

  • Filters elements based on a condition
  • Orders the elements of a sequence
  • Projects each element of a sequence into a new form
  • Specifies the data source
In LINQ to DataSet, the from clause is used to specify the data source from which the query will retrieve data. It establishes the initial dataset on which subsequent operations like filtering, projection, and ordering can be performed.

You want to retrieve a single value (e.g., the total number of records) from a SELECT statement. Which ADO.NET method would you use for this purpose?

  • ExecuteScalar
  • ExecuteNonQuery
  • ExecuteReader
  • ExecuteXmlReader
The correct option is ExecuteScalar. This method is used to execute a query that returns a single value, such as a count, sum, or average. It is commonly used when you need to retrieve aggregate information from the database without fetching a full result set.

What is the primary benefit of using LINQ in C#?

  • Higher performance compared to traditional SQL queries
  • Improved code readability and maintainability
  • Limited support for complex data structures
  • Reduced flexibility in querying data
LINQ improves code readability and maintainability by allowing developers to write queries using familiar syntax directly in their C# code. This makes it easier to express complex data manipulations and query operations in a more natural and intuitive way.

What is a database transaction in the context of ADO.NET?

  • A database connection
  • A database operation
  • A database query
  • A unit of work performed on a database
A database transaction in the context of ADO.NET refers to a unit of work performed on a database that is treated as a single operation. It either completes entirely or fails entirely, ensuring data integrity. Transactions are crucial for maintaining consistency and reliability in database operations.

What SQL statement is used to retrieve data from a database in ADO.NET?

  • FETCH
  • QUERY
  • SEARCH
  • SELECT
In ADO.NET, the SQL statement used to retrieve data from a database is "SELECT". This statement is used to specify which columns to retrieve from one or more tables in the database.

How does Entity Framework facilitate LINQ queries against the database?

  • By automatically converting LINQ queries into stored procedures.
  • By directly querying in-memory collections without involving the database.
  • By providing a built-in SQL query editor within Visual Studio.
  • By translating LINQ queries into SQL queries that can be executed by the database.
Entity Framework facilitates LINQ queries against the database by translating LINQ queries written in C# syntax into SQL queries that can be executed against the underlying database. This allows developers to use familiar LINQ syntax to interact with data in the database without needing to write SQL directly.

The "Find" method in Entity Framework is used to retrieve an entity by its ___________.

  • Foreign Key
  • Identity Column
  • Index
  • Primary Key
The "Find" method in Entity Framework is specifically designed to retrieve an entity by its primary key. It's a convenient way to fetch an entity based on its unique identifier without needing to write explicit LINQ queries. This method provides efficient retrieval of entities when you know the primary key value.

Parameterized queries help mitigate the risk of ________ attacks.

  • Cross-site request forgery
  • Cross-site scripting
  • Denial-of-Service
  • SQL injection
Parameterized queries play a crucial role in mitigating the risk of SQL injection attacks. SQL injection attacks occur when malicious SQL statements are inserted into input fields, potentially allowing attackers to execute unauthorized queries or manipulate data. By using parameterized queries, user input is treated as data rather than executable code, effectively preventing SQL injection by separating SQL logic from user input.

What is the primary purpose of connection pooling in ADO.NET?

  • To increase security of database connections
  • To minimize the overhead of opening and closing database connections
  • To optimize query execution in the database server
  • To reduce memory consumption in the application
Connection pooling in ADO.NET primarily aims to minimize the overhead of opening and closing database connections. When connection pooling is enabled, instead of completely closing a connection, it is returned to a pool where it can be reused by subsequent requests, thus reducing the overhead of establishing new connections. This optimization enhances the performance of applications that frequently interact with the database.

Exception handling in non-query command execution involves using ___________ to catch and handle errors.

  • if-else statements
  • switch-case statements
  • try-catch blocks
  • while loops
Exception handling in programming involves anticipating and handling errors or exceptional situations that may occur during the execution of code. In many programming languages, including JavaScript and Java, try-catch blocks are commonly used for exception handling. Within a try-catch block, you place the code that you expect might cause an error, and then use catch to handle any resulting exceptions.