The use of ___________ can help in caching query results and improving query performance.
- AsNoTracking()
- FirstOrDefault()
- Include()
- ToList()
The correct answer is AsNoTracking(). By using AsNoTracking(), Entity Framework Core does not keep track of the entities retrieved from the database, which can help in caching query results and improving query performance, especially in read-only scenarios where entities are not modified.
What is the primary purpose of the DbContext class in Entity Framework?
- To define the mapping between entity classes and database tables
- To define the structure of the database and manage migrations
- To handle database transactions and concurrency
- To represent a session with the database and provide APIs for querying and saving data
The DbContext class in Entity Framework serves as the primary entry point for interacting with the database. It represents a session with the database and provides APIs for querying and saving data. DbContext also manages the connection to the database, tracks changes to entities, and facilitates change tracking, which is essential for implementing features like lazy loading and change tracking.
In ADO.NET, what is the primary role of the DataAdapter?
- Executes SQL commands and returns a result set
- Provides a forward-only, read-only cursor for accessing data
- Represents a connected architecture for interacting with a database
- Retrieves data from the database and populates a DataSet
The primary role of the DataAdapter in ADO.NET is to retrieve data from the database and populate a DataSet. It acts as a bridge between the database and the DataSet, facilitating communication and data transfer.
The Entity Framework enables developers to work with data using a ___________-first approach.
- Code
- Data
- Database
- Model
The Entity Framework enables developers to work with data using a code-first approach. In this approach, you define your model classes first, and then the database schema is generated based on those classes.
Data binding to list controls like ListBox and DropDownList is often used to present data to users in a ___________ format.
- Tabular
- Hierarchical
- Linear
- Sequential
The correct answer is "Linear." Data binding to list controls like ListBox and DropDownList usually presents data to users in a linear format, where each data item is displayed one after the other, typically in a single column. This format is suitable for displaying lists of options or items.
When using the UPDATE command, you typically specify a ___________ clause to identify the rows to be updated.
- FROM
- JOIN
- SET
- WHERE
In SQL, the UPDATE command is used to modify existing records in a table. The WHERE clause is used to specify which rows should be updated based on certain conditions. For example, you might use WHERE to update only the rows where a certain column equals a specific value.
Scenario: You have a DataSet containing sales data, and you need to retrieve all sales records for a specific product category using LINQ to DataSet. Which LINQ clause would you use for filtering the data?
- From
- OrderBy
- Select
- Where
In LINQ to DataSet, the Where clause is used for filtering data based on specified criteria. It allows you to specify conditions to filter the data and retrieve only the records that match those conditions. For this scenario, using the Where clause enables you to filter sales records based on the product category, thus achieving the desired result.
Why are stored procedures commonly used in database applications?
- Stored procedures enhance security by controlling access to database objects and enforcing data integrity.
- Stored procedures facilitate collaboration among developers by providing a centralized code repository.
- Stored procedures improve performance by reducing network traffic and promoting code reuse.
- Stored procedures simplify application development by encapsulating complex business logic.
Stored procedures are commonly used in database applications for several reasons. They improve performance by reducing network traffic, as only the name of the stored procedure and any parameters need to be transmitted instead of the full SQL statements. They promote code reuse by encapsulating frequently used logic, reducing redundancy and making maintenance easier. Stored procedures also enhance security by controlling access to database objects and enforcing data integrity rules. Additionally, they can simplify application development by providing a standardized interface to complex business logic.
The Repeater control allows developers to create ________ HTML or other markup for each item in a dataset.
- Conditional
- Custom
- Dynamic
- Static
The Repeater control in ADO.NET allows developers to dynamically generate HTML or other markup for each item in a dataset. This means that the markup can be generated based on the data retrieved from the dataset, providing flexibility in the presentation of the data.
In ADO.NET, the ___________ property of a command object specifies the maximum amount of time a command can run before being terminated.
- CommandTimeout
- CommandDuration
- TimeoutDuration
- ExecutionTimeLimit
The correct option is CommandTimeout. In ADO.NET, the CommandTimeout property of a command object allows you to specify the maximum amount of time (in seconds) that a command can execute before it is terminated. This property is useful in scenarios where you want to control the execution time of commands, preventing long-running queries from affecting application performance or causing timeouts.