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.
What does "EF" stand for in the context of ADO.NET?
- Entity Facade
- Entity Factory
- Entity Flow
- Entity Framework
Entity Framework (EF) stands for Entity Framework. It is an Object-Relational Mapping (ORM) tool provided by ADO.NET, facilitating developers to work with relational data as domain-specific objects, eliminating the need for most of the data access plumbing code.
In ADO.NET Entity Framework, the [Key] attribute is often used to specify the ___________ property of an entity.
- Foreign
- Identity
- Navigation
- Primary
The [Key] attribute in Entity Framework is commonly applied to specify the identity property of an entity, indicating the property that uniquely identifies each instance of the entity.
When multiple users are modifying the same data concurrently, ___________ can help ensure data integrity.
- Constraints
- Isolation
- Locking
- Transactions
In scenarios where multiple users are modifying the same data concurrently, concurrency control mechanisms such as locking can help ensure data integrity by preventing conflicting modifications from occurring simultaneously.
Scenario: Your ADO.NET application is experiencing performance issues, and you suspect that connection pooling might be the cause. How can you investigate and optimize the connection pool settings?
- Adjust the "Min Pool Size" setting in the connection string
- Check the "Max Pool Size" setting in the connection string
- Evaluate the "Connection Lifetime" setting in the connection string
- Monitor the number of connections in use and the connection wait time
Monitoring the number of connections in use and the connection wait time is essential to understand the current utilization of the connection pool and identify any potential bottlenecks. By adjusting the pool size settings, such as "Max Pool Size" and "Min Pool Size," and evaluating parameters like "Connection Lifetime," you can optimize the connection pool for better performance.
Scenario: You want to find all the products that are in stock and have a price greater than $50. Which LINQ operators would you combine to achieve this in a single query?
- Where and Select
- Where and OrderBy
- Where and GroupBy
- Where and Any
The correct option is Where and Select. You would use the Where operator to filter the products that are in stock and have a price greater than $50, and then use the Select operator to project the results into a new collection containing only the required product information. This combination allows you to filter and select the desired products in a single query.
A SELECT statement is used to retrieve data from one or more ___________ in a database.
- Columns
- Databases
- Rows
- Tables
In SQL, the SELECT statement retrieves data from one or more tables in a database. It allows you to specify which columns to retrieve and may include conditions to filter rows. The fundamental purpose of the SELECT statement is to fetch data from the database tables.
Avoid using ___________ queries in LINQ as they can lead to performance issues when working with large datasets.
- Complex
- Long
- Nested
- Recursive
Recursive queries in LINQ can cause performance degradation, especially with large datasets, due to the iterative nature of their execution. It's recommended to avoid them for better performance.
What is the primary role of DbSet in Entity Framework?
- Executes raw SQL queries against the database.
- Handles database connections and transactions.
- Manages database migrations and schema changes.
- Represents a collection of entities of a specified type in the context.
DbSet in Entity Framework represents a collection of entities of a specified type in the context. It allows developers to perform CRUD operations (Create, Read, Update, Delete) on entities of that type within the context, providing a high-level abstraction over database tables.