Scenario: You want to update an existing order's shipping address in a SQL Server database using LINQ to SQL. Which LINQ to SQL method or operation is appropriate for this situation?
- Attach
- InsertOnSubmit
- SubmitChanges
- Update
SubmitChanges method is appropriate for updating existing records in a LINQ to SQL data context. After making changes to the object properties, calling SubmitChanges persists those changes to the database. Attach is used to attach existing objects to a data context, not for updates. Update is not a direct method in LINQ to SQL for updating records. InsertOnSubmit is used for inserting new records, not for updating existing ones.
In data binding, what is the role of the data source?
- Displaying data in a user-friendly format
- Executing SQL commands
- Formatting data for display
- Providing access to data
The data source in data binding acts as the provider of data to be bound to controls. It could be a database, XML file, or any other source containing the required data. The data source serves as the bridge between the application and the underlying data, facilitating seamless interaction between them.
What role does the AcceptChanges method play in data concurrency management in ADO.NET?
- It applies any pending changes to the DataRow and resets its state to unchanged.
- It discards any pending changes made to the DataRow and keeps its state as unchanged.
- It marks the DataRow for deletion and removes it from the DataTable.
- It rolls back any pending changes made to the DataRow and keeps its state as modified.
In ADO.NET, the AcceptChanges method is used in data concurrency management to apply any pending changes to the DataRow and reset its state to unchanged. This method is typically called after updating a DataRow to commit the changes to the underlying database and ensure data integrity.
How does data binding work with the Repeater and DataList controls, and how does it differ from other data controls?
- It binds directly to a data source by setting its DataSource property to a valid data source object such as a DataTable or DataSet.
- It requires explicit binding in the code-behind file by calling the DataBind() method.
- It retrieves data from the data source and binds it to the control by iterating over the data and generating the appropriate HTML for each item.
- It retrieves data from the data source and stores it in view state for future use.
Data binding in the Repeater and DataList controls differs from other data controls in that it does not have built-in support for automatically generating its content based on the data source. Instead, it provides greater flexibility by allowing developers to customize the HTML markup for each item. This approach gives more control over the presentation of data but requires more manual coding compared to controls like GridView or DataGrid.
Which approach allows you to define entity classes and then generate a database schema from those classes in Entity Framework?
- Code First
- Database First
- Model First
- Schema First
Code First approach in Entity Framework allows developers to define entity classes in code and then generate a database schema from those classes. This approach is particularly useful when starting a new project or when the database schema can be derived from the application's domain model.
When working with complex hierarchical data, DataRelations help maintain ___________ between related tables.
- Associations
- Connections
- Links
- Relationships
DataRelations in ADO.NET maintain relationships between related tables, facilitating navigation and querying of hierarchical data structures such as parent-child relationships.
A DataAdapter acts as a bridge between a DataSet and a ___________.
- Connection
- DataReader
- Database
- Table
A DataAdapter serves as a bridge between a DataSet and a database connection. It helps in transferring data between the DataSet and the data source, facilitating data retrieval and manipulation.
What does LINQ stand for in the context of ADO.NET Entity Framework?
- Language-Integrated Query
- Lightweight Integration Query
- Linked-Index Query
- Localized-Integration Query
Language-Integrated Query (LINQ) is a set of features introduced in .NET Framework that allows for querying data from different data sources using a unified syntax. In the context of ADO.NET Entity Framework, LINQ provides a way to query entities using familiar C# or VB.NET syntax, making it easier to work with database data in an object-oriented manner.
To improve performance, you can use ___________ in LINQ to Entities to reduce the amount of data retrieved from the database.
- Lazy Loading
- Eager Loading
- Deferred Execution
- Query Optimization
The correct option is "Eager Loading". In LINQ to Entities, eager loading is used to fetch related data along with the main query to reduce the number of database round-trips. It retrieves the main entity as well as its related entities in a single query, which can improve performance by reducing the amount of data retrieved from the database. Eager loading helps in optimizing queries and reducing the overhead of lazy loading or multiple round-trips to the database.
The LINQ to Entities query syntax resembles ___________ SQL.
- Declarative
- Imperative
- Object-oriented
- Procedural
The LINQ to Entities query syntax resembles Declarative SQL. It allows developers to write queries in a way that is similar to SQL, focusing on what data should be retrieved rather than how.