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.
How can you create a filtered view of data from a DataSet using DataViews?
- Use the DataView.Filter method to apply a filter expression to the DataView.
- Use the DataView.RowFilter property to specify filter criteria based on column values.
- Use the DataView.RowStateFilter property to filter rows based on their state (e.g., Added, Modified, Deleted).
- Use the DataView.Select method to select specific rows from the DataView.
To create a filtered view of data from a DataSet using DataViews, you can use the RowFilter property of the DataView. This property allows you to specify filter criteria based on column values, thereby creating a filtered view of the data according to your requirements.
One of the advantages of data binding is that it helps in keeping the UI and ___________ in sync.
- Business logic
- Data manipulation
- Database
- Presentation
One of the advantages of data binding is that it helps in keeping the UI and presentation in sync with the underlying data, ensuring consistency between what is displayed and what is stored.
Scenario: Your application uses Entity Framework extensively, and you notice that some queries are slow. What steps can you take to identify and address performance bottlenecks in Entity Framework?
- Analyzing generated SQL queries for inefficiencies
- Ensuring proper indexing on database tables
- Implementing caching mechanisms to reduce database hits
- Using database profiling tools to identify slow queries
Analyzing generated SQL queries helps identify any inefficient queries that might be causing performance issues. Database profiling tools provide insights into query execution times and help pinpoint slow queries. Ensuring proper indexing on database tables can significantly improve query performance. Implementing caching mechanisms reduces the need for frequent database hits, enhancing overall performance.
What is the role of the CommandTimeout property in an ADO.NET command object?
- Specifies the maximum number of retries for the command execution
- Specifies the maximum time in seconds for the command to execute before throwing an exception
- Specifies the minimum time in milliseconds for the command to execute
- Specifies the wait time in milliseconds between command executions
The CommandTimeout property in an ADO.NET command object specifies the maximum time in seconds for the command to execute before throwing a timeout exception. It allows developers to control the duration of command execution, preventing long-running queries from causing performance issues or blocking the application. By setting an appropriate CommandTimeout value, developers can balance the need for timely responses with the complexity of database operations, ensuring optimal application responsiveness and user experience.
What is the role of the "AsNoTracking" method in Entity Framework, and when is it useful?
- Allows parallel tracking of entities, useful in multi-threaded applications
- Disables the tracking of entities retrieved from the database, useful when entities are read-only or won't be modified
- Enhances database query performance, useful in high-load environments
- Tracks entities retrieved from the database, useful when entities need to be modified
The "AsNoTracking" method in Entity Framework disables the tracking of entities, which means that any changes made to those entities won't be tracked by the context. This is useful when working with read-only data or when entities won't be modified, as it improves performance by avoiding the overhead of tracking changes.