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.
The let keyword in LINQ is used to define ___________ that can be reused within the query.
- Constants
- Functions
- Objects
- Variables
In LINQ, the let keyword is used to define variables that can be reused within the query. These variables allow for cleaner and more readable code by providing a way to store intermediate results or calculations for later use within the query.
When using LINQ to DataSet, the let keyword is used to define ___________ variables within a query.
- Temporary
- Global
- Static
- Local
The correct option is 'Temporary'. In LINQ to DataSet, the let keyword is used to define temporary variables within a query. These variables can hold intermediate results or calculated values that are used within the query itself. They are scoped to the query in which they are defined and are not accessible outside of it.
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.
Which data provider is used for connecting to MySQL databases in ADO.NET?
- MySqlClient
- OleDb
- OracleClient
- SqlClient
The MySqlClient data provider is specifically designed for connecting to MySQL databases in ADO.NET applications. It offers optimized performance, support for MySQL-specific features, and seamless integration with ADO.NET, enabling developers to interact with MySQL databases efficiently and effectively. Using the MySqlClient data provider ensures reliable connectivity and compatibility with MySQL database functionalities within ADO.NET applications.