To optimize LINQ to Entities queries, consider using the ___________ method to specify what data to include in the result set.
- FirstOrDefault()
- Include()
- Skip()
- ToList()
The correct answer is Include(). The Include() method is used to specify related entities to include in the query result set. This can help optimize LINQ to Entities queries by fetching related data in a single round trip to the database, reducing the number of subsequent database calls for related data.
In LINQ to SQL, how can you retrieve a single record based on specific criteria?
- ExecuteQuery method
- ExecuteScalar method
- FirstOrDefault method
- Single method
When using LINQ to SQL, the FirstOrDefault method is used to retrieve a single record based on specific criteria. This method returns the first element of a sequence that satisfies a specified condition or a default value if no such element is found.
You have a LINQ query that performs multiple joins and retrieves a large dataset. What steps can you take to optimize the query's performance?
- Filtering Data
- Paging Results
- Proper Indexing
- Using IQueryable instead of IEnumerable
Proper Indexing: Indexing plays a crucial role in optimizing query performance, especially in scenarios involving multiple joins and large datasets. By ensuring that appropriate indexes are created on the columns used in joins and filtering conditions, you can significantly enhance query execution speed by allowing the database engine to quickly locate the required data. This optimization reduces the need for full table scans and improves overall query efficiency.
Which ADO.NET class represents a single table of in-memory data?
- DataTable
- SqlCommand
- SqlConnection
- SqlDataAdapter
The DataTable class in ADO.NET represents a single table of in-memory data. It provides methods and properties to manipulate and interact with the data stored in the table, such as adding rows, deleting rows, or performing queries. It is commonly used for data manipulation and caching within applications.
Scenario: You want to optimize a LINQ to Entities query to minimize the number of database round-trips. What technique or method can you use for this purpose?
- Eager Loading
- Lazy Loading
- Explicit Loading
- AsNoTracking
The correct option is 1. Eager Loading is a technique used in LINQ to Entities to optimize queries by retrieving related data along with the main query results in a single database round-trip. It preloads related entities in advance, reducing subsequent database calls and improving performance.
In Entity Framework, you can improve performance by using ___________ for executing raw SQL queries.
- DbSet
- LINQ
- Stored Procedures
- Entity Framework Core
The correct option is "Stored Procedures." Entity Framework allows developers to execute raw SQL queries for performance optimization. Utilizing stored procedures can offer several benefits, including reduced network traffic, precompiled execution plans, and enhanced security through parameterized queries.
What is the significance of the "Connection Lifetime" property in connection string settings?
- It defines the minimum time a connection must remain open before being reused, It controls the encryption level used for securing the connection, It specifies the maximum duration a connection can remain idle in the pool before being discarded, It determines the maximum number of connections allowed in the pool
- It determines the maximum number of connections allowed in the pool, It defines the minimum time a connection must remain open before being reused, It controls the encryption level used for securing the connection, It specifies the maximum duration a connection can remain idle in the pool before being discarded
- It determines the maximum number of connections allowed in the pool, It defines the minimum time a connection must remain open before being reused, It specifies the maximum duration a connection can remain idle in the pool before being discarded, It controls the encryption level used for securing the connection
- It specifies the maximum duration a connection can remain idle in the pool before being discarded, It determines the maximum number of connections allowed in the pool, It defines the minimum time a connection must remain open before being reused, It controls the encryption level used for securing the connection
The "Connection Lifetime" property in connection string settings specifies the maximum duration a connection can remain idle in the pool before being discarded, helping to manage resource usage and prevent stale connections.
Data binding in ADO.NET allows you to connect what to a user interface?
- Database records
- SQL queries
- Stored procedures
- User interface controls
Data binding in ADO.NET enables the connection of user interface controls, such as textboxes, labels, and datagrids, to database records. This linkage allows for automatic synchronization of data between the database and the user interface, simplifying data presentation and manipulation tasks within the application.
What is the primary purpose of a DataTable in ADO.NET?
- Represents a connection to the database
- Represents a query to be executed on the database
- Represents a single table of in-memory data
- Stores a collection of records from a database
A DataTable in ADO.NET represents an in-memory representation of a single table from a database. It allows manipulation of data locally without directly interacting with the database. This can be useful for caching data, performing calculations, or preparing data for display.
Scenario: You are designing a data-driven application, and you need to work with multiple related tables. Which ADO.NET feature will help you manage these relationships effectively?
- DataAdapter
- DataReader
- DataRelation
- DataSet
Detailed A DataRelation in ADO.NET helps in managing relationships between multiple related tables effectively. It allows defining parent-child relationships between DataTables, which facilitates operations like navigation, constraint enforcement, and maintaining data integrity. Utilizing DataRelations enables efficient querying and manipulation of data across related tables.