Performance optimization in hierarchical data involves techniques like ___________ to reduce data retrieval overhead.
- Aggressive loading
- Deferred loading
- Eager loading
- Lazy loading
In hierarchical data, deferred loading techniques are employed to optimize performance by loading related data only when necessary, minimizing the amount of data retrieved from the database at once.
Scenario: You need to implement a custom conflict resolution strategy in your ADO.NET application. What event should you handle to achieve this?
- RowChanged
- RowChanging
- RowUpdated
- RowUpdating
To implement a custom conflict resolution strategy in an ADO.NET application, you should handle the RowUpdating event. This event occurs before changes are sent to the database during an Update operation. By handling this event, you can examine the changes being made and implement your custom logic to resolve conflicts before they are applied to the database.
In LINQ to DataSet, what is the purpose of the join clause?
- To combine data from two or more data sources based on a related column between them
- To filter data based on a specified condition
- To group data based on a common attribute
- To sort data in ascending or descending order
In LINQ to DataSet, the join clause is used to combine data from two or more data sources based on a related column between them. It allows you to perform operations similar to SQL joins, such as inner joins, outer joins, and cross joins, to retrieve and process data from multiple tables or collections simultaneously. Understanding how to use the join clause effectively is essential for querying and manipulating data using LINQ to DataSet.
Scenario: You are tasked with calculating the total revenue for each product category from a DataSet containing sales data. How would you achieve this using LINQ to DataSet?
- Aggregate
- GroupBy
- Select
- Sum
In LINQ to DataSet, the GroupBy clause is used to group records based on a specified key. By grouping sales data by product category, you can then calculate the total revenue for each category. Thus, using GroupBy followed by an aggregation function like Sum allows you to achieve the task of calculating total revenue for each product category.
When working with the Oracle database, you would use the ___________ data reader.
- MySqlDataReader
- OleDbDataReader
- OracleDataReader
- SQLDataReader
When interacting with an Oracle database in .NET applications, the appropriate data reader to use is the OracleDataReader. This specialized data reader is designed specifically for working with Oracle databases, providing efficient access to query results and handling Oracle-specific data types and features. Using the correct data reader ensures compatibility and optimal performance when retrieving data from an Oracle database.
How can you improve the performance of a LINQ query that involves multiple joins and filtering conditions?
- Add more filtering conditions to refine the result set
- Increase the number of data retrieval operations
- Remove joins to simplify the query
- Use appropriate indexes on columns involved in joins and filters
Improving the performance of LINQ queries with multiple joins and filtering conditions involves using appropriate indexes on columns involved in joins and filters. This helps in optimizing data retrieval and processing, resulting in better query performance.
Migrations in Entity Framework Code-First are used to keep the database schema _________ with the application's data model.
- Consistent
- Independent
- Isolated
- Synchronized
Migrations in Entity Framework Code-First ensure that the database schema remains consistent with the application's data model as it evolves over time. They allow you to update the database schema automatically based on changes to your entity classes.
Master-detail data binding is commonly used when displaying ___________ relationships from a database.
- One-to-One
- One-to-Many
- Many-to-One
- Many-to-Many
Master-detail data binding in ADO.NET is typically used to display one-to-many relationships from a database, making the correct option "One-to-Many".
Scenario: You are building a database-driven application, and you need to add new records to a database table. Which ADO.NET command would you use for this task?
- SqlCommand.ExecuteNonQuery()
- SqlCommand.ExecuteQuery()
- SqlCommand.ExecuteScalar()
- SqlCommand.ExecuteXmlReader()
SqlCommand.ExecuteNonQuery() is the appropriate ADO.NET command for executing data manipulation language (DML) queries such as INSERT, UPDATE, DELETE, and MERGE. This command is used specifically for executing queries that do not return any result set, making it suitable for tasks like adding new records to a database table.
In Entity Framework, the concept of ___________ allows you to customize how properties in an entity map to columns in a database table.
- Code-First Migrations
- Data Annotations
- Entity Framework Code-First
- Entity Framework Core
In Entity Framework, the concept of "Data Annotations" allows you to customize how properties in an entity map to columns in a database table. Data Annotations provide a way to override the default mapping behavior by specifying attributes directly on your entity classes. Examples include [Key] to define a primary key, [Column] to specify column names, and [MaxLength] to set column length constraints.