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."
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.
Can you perform data editing and updates directly within a DataGrid or DataGridView control?
- No, DataGrid and DataGridView controls are primarily for display purposes and do not support data editing or updates.
- Yes, DataGrid and DataGridView controls allow users to perform data editing and updates directly within the grid interface.
- Yes, but it requires additional plugins or extensions to enable data editing and updates within the grid.
- Yes, but only through complex coding and custom implementations.
Yes, DataGrid and DataGridView controls provide built-in support for data editing and updates directly within the grid interface, offering a convenient way for users to interact with the data without requiring additional forms or dialog boxes. This feature streamlines data manipulation tasks and improves user productivity.
The DELETE command in ADO.NET is used to ___________ data from a database.
- Delete
- Insert
- Select
- Update
In ADO.NET, the DELETE command is specifically designed to remove data from a database table. It's commonly used to delete one or more rows from a table based on specified criteria.
In ADO.NET, the two-phase commit protocol is used to ensure consistency in ___________ transactions.
- distributed
- isolated
- nested
- parallel
In ADO.NET, the two-phase commit protocol is used to ensure consistency in distributed transactions. The two-phase commit protocol coordinates transactions that involve multiple resources (such as databases) distributed across different systems, ensuring that either all transactions commit or all transactions rollback, thus maintaining data integrity and consistency.