Scenario: Your project involves interacting with a SQL Server database. Which LINQ technology is the most appropriate choice for querying and manipulating data in the database?
- LINQ to Entities
- LINQ to Objects
- LINQ to SQL
- LINQ to XML
LINQ to SQL is specifically designed for querying and manipulating data in SQL Server databases. It allows developers to write LINQ queries directly against the database entities, providing a strongly-typed approach to database access and manipulation.
How does Entity Framework handle database schema changes in a Code-First approach?
- Entity Framework automatically updates the database schema without requiring any manual intervention from developers.
- Entity Framework generates a new database schema from scratch with each change, discarding existing data.
- Entity Framework generates migration files that represent incremental changes to the database schemDevelopers can apply these migrations to update the database schema without losing data.
- Entity Framework prompts developers to manually update the database schema by executing SQL scripts.
In a Code-First approach with Entity Framework, database schema changes are managed through migrations. When developers modify the application's data model, Entity Framework generates migration files that represent these changes. Developers can then apply these migrations to update the database schema incrementally. Entity Framework tracks the history of migrations applied to the database, allowing developers to roll back changes if needed. This approach enables developers to evolve the database schema alongside the application's data model while preserving existing data.
Data readers are typically used for which type of database operations?
- Creating new database objects
- Deleting database objects
- Reading data from the database
- Updating data in the database
Data readers in ADO.NET are primarily used for reading data from the database. They provide a lightweight and efficient way to sequentially retrieve query results, allowing applications to process large datasets without the overhead of loading the entire result set into memory. While data readers excel at data retrieval operations, they are not designed for updating or modifying data in the database, as they provide read-only access to query results.
The where clause in LINQ is used for ___________ elements based on specified criteria.
- Aggregating
- Filtering
- Grouping
- Sorting
The where clause in LINQ is primarily used for filtering elements based on specified criteria, allowing developers to select only those that meet certain conditions.
Your application requires calling a stored procedure that retrieves a single value from the database. What steps would you follow to execute the stored procedure and retrieve the result?
- Execute the stored procedure using SqlCommand.ExecuteNonQuery method, then retrieve the single value using SqlCommand.Parameters collection.
- Execute the stored procedure using SqlCommand.ExecuteScalar method to directly retrieve the single value.
- Use SqlCommand.ExecuteReader method to execute the stored procedure and retrieve the single value from SqlDataReader.
- Use SqlDataAdapter to execute the stored procedure and retrieve the single value from DataSet.
SqlCommand.ExecuteScalar method is the correct option. It executes the query and returns the first column of the first row in the result set returned by the query. This method is typically used for executing commands such as SELECT statements that return a single value.
What is the advantage of using LINQ to SQL for CRUD operations compared to traditional SQL queries?
- LINQ to SQL allows for better integration with other .NET languages
- LINQ to SQL provides better performance
- LINQ to SQL queries are easier to write and understand
- LINQ to SQL supports only SQL Server databases
One advantage of using LINQ to SQL for CRUD operations is that LINQ queries are more expressive and easier to write and understand compared to traditional SQL queries. LINQ to SQL provides a higher level of abstraction, allowing developers to focus on querying data rather than dealing with low-level SQL syntax.
Scenario: You are working on an application where multiple users can update customer information stored in a dataset simultaneously. What approach would you use to handle data conflicts and ensure data integrity?
- Implementing manual locking mechanisms
- Using automatic conflict resolution mechanisms
- Using optimistic concurrency control
- Using pessimistic concurrency control
Optimistic concurrency control involves assuming that conflicts between multiple users are rare, allowing each user to work with the data independently. It checks for conflicts only at the time of saving changes, reducing the likelihood of blocking user actions. This approach ensures better scalability and user responsiveness.
Which ADO.NET data provider is commonly used for Microsoft SQL Server databases?
- MySQL Data Provider
- OLE DB Data Provider
- Oracle Data Provider for .NET
- SQL Server Data Provider
The SQL Server Data Provider is specifically designed for interacting with Microsoft SQL Server databases in ADO.NET applications. It offers optimized performance and features tailored for SQL Server, making it the preferred choice when working with SQL Server databases within the .NET framework.
Which part of Entity Framework is responsible for translating LINQ queries into SQL queries?
- Entity Client
- Entity Data Model
- Object Services
- Query Provider
The Query Provider is the part of Entity Framework responsible for translating LINQ queries written in .NET languages (such as C# or VB.NET) into equivalent SQL queries that can be executed against the underlying database. This translation process is crucial for enabling developers to use LINQ to query databases without having to write SQL queries explicitly.
The CommandType property of a command object can be set to _______ when executing a stored procedure.
- StoredProcedure
- TableDirect
- Text
- View
The CommandType property of a command object is set to StoredProcedure when executing a stored procedure. This tells the command object that the CommandText property contains the name of a stored procedure to execute.