What does LINQ stand for?
- Language Integrated Query
- Linked Interaction Query
- Local Interconnected Query
- Longitudinal Inequality Query
LINQ stands for Language Integrated Query. It is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages. It allows developers to query different types of data sources in a uniform way.
Scenario: You are building a high-performance application that requires reading a large dataset from a database. How can you efficiently achieve this using a data reader?
- Use SqlDataReader's ExecuteReaderAsync method
- Use SqlDataReader's Forward-Only Cursor
- Use SqlDataReader's Scrollable Cursor
- Use SqlDataReader's UpdateBatchSize property
Utilizing SqlDataReader's Forward-Only Cursor mode provides the most efficient way to read a large dataset from a database. This mode allows for a single-pass read-through of the data, reducing the overhead associated with maintaining a scrollable cursor or performing asynchronous operations. Scrollable cursors, UpdateBatchSize property, and ExecuteReaderAsync method might introduce unnecessary overhead or complexity in scenarios where a simple, efficient read-through is sufficient.
What is the purpose of the SaveChanges method in Entity Framework when updating data?
- It creates a backup of the current state of entity objects in the context before applying any modifications.
- It discards any changes made to entities in the context without affecting the underlying database.
- It persists all pending changes made to entities in the context to the underlying database.
- It retrieves the latest version of data from the database and updates the entity objects in the context.
The SaveChanges method in Entity Framework is used to persist all pending changes made to entity objects in the context to the underlying database. This includes inserting new records, updating existing ones, and deleting entities as necessary. By calling SaveChanges, the framework ensures that any modifications made within the context are correctly synchronized with the database, maintaining data consistency. This method is essential when updating data as it commits the changes made by the application, making them permanent in the database.
When working with LINQ to Entities, the "Include" method is used to specify ___________ properties to be eagerly loaded.
- Associated
- Joined
- Navigation
- Related
In LINQ to Entities, the "Include" method is used to specify navigation properties to be eagerly loaded. Navigation properties are properties on an entity that allow you to navigate to related entities.
LINQ allows developers to query and manipulate which types of data sources?
- Arrays
- Collections
- Databases
- XML
LINQ (Language Integrated Query) enables developers to query and manipulate collections, databases, XML documents, and any data source that can be queried with LINQ. It's a versatile tool for working with different types of data sources, making it easier to write expressive and powerful queries in C# and other .NET languages.
You are developing an application that needs to retrieve data from an Oracle database and update it using a DataSet. Which type of DataAdapter would you use for this scenario?
- MySqlDataAdapter
- OleDbDataAdapter
- OracleDataAdapter
- SqlDataAdapter
The OracleDataAdapter is specifically designed to work with Oracle databases, making it the appropriate choice for retrieving and updating data from an Oracle database using a DataSet. It provides optimized performance and native support for Oracle databases.
In WinForms, which event is often used to trigger data binding updates?
- ControlChanged
- DataBindingComplete
- DataBindingUpdated
- DataSourceUpdated
In WinForms, the DataSourceUpdated event is often used to trigger data binding updates. This event occurs after the data source has been updated with the new value from the control, allowing for additional processing or validation to be performed.
When optimizing LINQ queries, using the ___________ method can help in reducing the number of database round trips.
- FirstOrDefault()
- Include()
- Skip()
- ToList()
The correct answer is ToList(). When you use ToList() method, it retrieves all the data from the database at once and then performs operations on it in memory. This can reduce the number of database round trips by fetching all data needed in a single trip, potentially improving performance.
In LINQ, what is the purpose of the select clause?
- To filter the results
- To join the results
- To project the results
- To sort the results
The purpose of the select clause in LINQ is to project the results. It allows you to define the shape of the result set by selecting specific fields or transforming the elements of the source sequence into a new form.
What does LINQ to SQL provide when working with relational databases?
- Asynchronous Queries
- Data Encryption
- Direct Access to SQL Server
- Object-Relational Mapping
LINQ to SQL provides object-relational mapping (ORM), allowing developers to work with relational databases using familiar object-oriented programming concepts. It facilitates the translation of relational data into objects, simplifying database operations in .NET applications.