Parameters in non-query commands help prevent ___________ attacks.
- Cross-Site Request Forgery (CSRF)
- Cross-Site Scripting (XSS)
- Denial of Service (DoS)
- SQL Injection
SQL Injection attacks occur when malicious SQL code is inserted into input fields of an application, potentially allowing an attacker to execute unauthorized SQL commands. By using parameters in non-query commands, such as prepared statements or parameterized queries, input values are treated as data rather than executable code, thereby reducing the risk of SQL Injection attacks.
Scenario: A user wants to delete a record from a dataset, but you want to ensure that the deletion is not permanent until the user confirms. What ADO.NET functionality can help you achieve this?
- Implementing a custom rollback mechanism
- Using DataAdapter's DeleteCommand property
- Using DataAdapter's Fill and Update methods
- Using DataTable's RejectChanges method
DataTable's RejectChanges method allows reverting changes made to a DataTable since it was loaded or since the last AcceptChanges call. By calling this method, you can undo deletion of records until changes are permanently saved to the database. This provides a safety net for users before committing irreversible changes.
You need to retrieve a list of customers from a database using LINQ to Entities. What LINQ operator would you use to filter customers whose last names start with "Smith"?
- Where
- StartsWith
- Contains
- Like
The correct option is "StartsWith." This operator is used in LINQ to Entities to filter records based on the beginning characters of a string. It's suitable for filtering last names that start with "Smith."
How can you define complex queries involving multiple tables in LINQ to Entities?
- By using navigation properties to traverse relationships between entities
- By using the "GroupBy" clause to group related entities
- By using the "OrderBy" clause to sort entities based on a specified key
- By using the "Select" clause to project specific properties from related entities
Complex queries involving multiple tables in LINQ to Entities can be defined by using navigation properties to traverse relationships between entities. Navigation properties allow you to navigate from one entity to related entities, enabling the construction of queries that involve multiple tables and their relationships.
How can you specify a connection string in a .NET application configuration file?
- By adding a
section and defining a element within it - By embedding the connection string directly into the code
- By using a predefined system variable
- By using a separate text file for storing connection strings
In .NET applications, connection strings are typically stored in the application configuration file (app.config or web.config). This can be done by adding a section within the configuration file and defining one or more elements, each containing the connection string details. This approach allows for easy maintenance and modification of connection strings without modifying the code.
When working with the Repeater and DataList controls, it's essential to consider _________ optimization for efficient rendering.
- Performance
- Memory
- Code
- Network
The correct option is "Performance." When using the Repeater and DataList controls, optimizing performance is crucial to ensure efficient rendering of data. Performance optimization techniques such as caching, data retrieval strategies, and minimizing server round trips can significantly enhance the responsiveness and scalability of web applications. Other options like "Memory," "Code," and "Network" are relevant factors but do not directly address the need for optimizing rendering performance in the context of these controls.
Two-way data binding in WinForms allows data to flow both from the data source to the control and from the control back to the ___________.
- Application Logic
- Data Source
- Database
- User Interface
Two-way data binding in WinForms enables synchronization between the data source and the control, allowing changes made in either the control or the data source to be reflected in the other. The data source can be a database, a collection, or any other data structure used in the application.
Scenario: You are developing a high-performance application using Entity Framework. What is one technique you can employ to reduce the number of database queries and improve query performance?
- Disabling lazy loading to prevent additional database trips
- Increasing the batch size for data retrieval
- Using eager loading to fetch related entities along with the main entity in a single query
- Utilizing stored procedures for complex data retrieval
Eager loading allows fetching related entities in a single query, minimizing the number of round trips to the database and enhancing performance. Increasing batch size might improve performance but doesn't directly address reducing the number of queries. Disabling lazy loading can lead to incomplete data retrieval. Stored procedures can enhance performance but may not necessarily reduce the number of queries.
The ___________ event in WinForms is commonly used to validate data before it is committed to the data source.
- ValidateData
- DataValidating
- ValidatingData
- Validating
The correct option is ValidatingData. This event is commonly used in WinForms applications to validate data before it is committed to the data source, providing an opportunity to ensure data integrity.
In LINQ to Entities, what does the "Include" method help achieve?
- Eager loading of related entities
- Filtering of query results
- Lazy loading of related entities
- Sorting of query results
The "Include" method in LINQ to Entities helps achieve eager loading of related entities. Eager loading fetches the related entities along with the main entity in a single query, reducing the need for subsequent database round-trips. This can improve performance by minimizing the number of database calls required to retrieve related data.