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.
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.
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 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.
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.
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.
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.
In WinForms, which event is often used to trigger data binding updates?
- ControlChanged
- DataBindingComplete
- DataBindingUpdated
- DataSourceUpdated
In WinForms, the DataSourceUpdated event is often used to trigger data binding updates. This event occurs after the data source has been updated with the new value from the control, allowing for additional processing or validation to be performed.
You are developing an application that needs to retrieve data from an Oracle database and update it using a DataSet. Which type of DataAdapter would you use for this scenario?
- MySqlDataAdapter
- OleDbDataAdapter
- OracleDataAdapter
- SqlDataAdapter
The OracleDataAdapter is specifically designed to work with Oracle databases, making it the appropriate choice for retrieving and updating data from an Oracle database using a DataSet. It provides optimized performance and native support for Oracle databases.
In LINQ, what is the purpose of the select clause?
- To filter the results
- To join the results
- To project the results
- To sort the results
The purpose of the select clause in LINQ is to project the results. It allows you to define the shape of the result set by selecting specific fields or transforming the elements of the source sequence into a new form.
When optimizing LINQ queries, using the ___________ method can help in reducing the number of database round trips.
- FirstOrDefault()
- Include()
- Skip()
- ToList()
The correct answer is ToList(). When you use ToList() method, it retrieves all the data from the database at once and then performs operations on it in memory. This can reduce the number of database round trips by fetching all data needed in a single trip, potentially improving performance.
In LINQ, what is deferred execution, and why is it important?
- It executes queries asynchronously to prevent blocking.
- It executes queries in parallel to improve performance.
- It is the immediate execution of queries to retrieve data.
- It postpones the execution of queries until the results are needed.
Deferred execution in LINQ means that the query is not executed immediately when it is defined, but rather when the results are actually accessed. This is important because it allows for more efficient use of resources by delaying the execution until necessary, which can lead to better performance and reduced memory consumption, especially when dealing with large datasets or complex queries.