Scenario: In a LINQ to DataSet query, you encounter the concept of deferred execution. Explain what deferred execution means and provide an example of when it might be advantageous.
- Execution of query happens after modifying the underlying data.
- Execution of query happens in parallel with other operations.
- Execution of query is immediate and results are generated as soon as the query is executed.
- Execution of query is postponed until the results are actually requested or iterated over.
Deferred execution means that the execution of the LINQ query is delayed until the results are actually needed. This postponement allows for better performance optimization, especially when dealing with large datasets, as it avoids unnecessary computations until the results are required. For example, when dealing with complex queries or when the query result is not immediately needed, deferred execution can be advantageous in terms of resource utilization.
Scenario: You are developing a Windows Forms application that needs to display and edit data from a database. Which ADO.NET component would you use to store and manage the data in a tabular format?
- DataSet
- SqlConnection
- SqlDataAdapter
- SqlDataReader
The DataSet class in ADO.NET is designed to store and manage data in a tabular format, making it suitable for use in Windows Forms applications where data needs to be displayed and edited. It provides a disconnected architecture, allowing data to be manipulated independently of the database.
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.
To optimize LINQ queries for performance, you can use the ___________ method to reduce the number of database calls.
- Aggregate
- AsQueryable
- Join
- Select
To optimize LINQ queries for performance, you can use the AsQueryable method to reduce the number of database calls. This method converts an IEnumerable collection to an IQueryable collection, allowing the query to be executed on the database server instead of in-memory. This can lead to significant performance improvements, especially when dealing with large datasets or complex queries.
To improve LINQ query performance, you can use the DataLoadOptions class to specify ___________ loading.
- Eager
- Lazy
- Deferred
- Immediate
Eager loading retrieves all related data at once, which can enhance performance by reducing the number of database calls. This is done using the LoadWith method of DataLoadOptions.
When executing an INSERT command, you can use ___________ to specify the values to be inserted.
- INTO clause
- SELECT clause
- VALUES clause
- WHERE clause
In an INSERT command in SQL, the VALUES clause is used to specify the values to be inserted into the specified columns of a table. It allows you to define the data that will be added to the table.