Scenario: You are working on an application where multiple users can update the same database record simultaneously. Which concurrency model would you recommend to handle potential conflicts in this scenario?
- Dirty Read Concurrency
- Optimistic Concurrency
- Pessimistic Concurrency
- Snapshot Concurrency
Optimistic concurrency is the preferred model for handling potential conflicts when multiple users can update the same record simultaneously. It assumes that conflicts are rare, allowing multiple users to access and modify the data concurrently. When a user attempts to commit changes, the system checks whether the data has been modified since it was last retrieved. If no modifications are detected, the changes are applied successfully.
The use of stored procedures can help improve ___________ and security in database applications.
- Efficiency
- Performance
- Reliability
- Scalability
The use of stored procedures can help improve performance and security in database applications. By precompiling SQL statements, stored procedures reduce the overhead of repeated compilation, leading to better performance. Furthermore, they enhance security by allowing controlled access to database objects and minimizing the risk of SQL injection attacks.
In DataGrid or DataGridView controls, you can enable data editing by setting the "___________" property.
- AllowEdit
- EditEnabled
- EditMode
- Editable
In DataGrid or DataGridView controls, you can enable data editing by setting the "EditMode" property to allow users to edit the data displayed in the control.
To optimize LINQ queries for performance, you can use the ___________ method to reduce the number of database calls.
- Aggregate
- AsQueryable
- Join
- Select
To optimize LINQ queries for performance, you can use the AsQueryable method to reduce the number of database calls. This method converts an IEnumerable collection to an IQueryable collection, allowing the query to be executed on the database server instead of in-memory. This can lead to significant performance improvements, especially when dealing with large datasets or complex queries.
To improve LINQ query performance, you can use the DataLoadOptions class to specify ___________ loading.
- Eager
- Lazy
- Deferred
- Immediate
Eager loading retrieves all related data at once, which can enhance performance by reducing the number of database calls. This is done using the LoadWith method of DataLoadOptions.
When executing an INSERT command, you can use ___________ to specify the values to be inserted.
- INTO clause
- SELECT clause
- VALUES clause
- WHERE clause
In an INSERT command in SQL, the VALUES clause is used to specify the values to be inserted into the specified columns of a table. It allows you to define the data that will be added to the table.
You need to improve the performance of a LINQ to SQL query that retrieves data from a large database. What actions can you take to achieve this?
- Executing Queries Asynchronously
- Optimizing Database Design
- Using Lazy Loading
- Utilizing Stored Procedures
Utilizing Stored Procedures: Stored procedures can be advantageous for improving the performance of LINQ to SQL queries, especially when dealing with large databases. By utilizing stored procedures, you can leverage pre-compiled execution plans, reduce network traffic, and enhance security through parameterized queries. This approach can lead to significant performance improvements by offloading query execution to the database server, resulting in optimized data retrieval and processing.
Entity Framework supports which database management systems (DBMS)?
- MySQL
- Oracle
- PostgreSQL
- SQL Server
Entity Framework supports various database management systems (DBMS) including SQL Server, MySQL, Oracle, and PostgreSQL, among others. It provides an abstraction layer that allows developers to work with different databases without needing to change their code significantly.
What happens if you call the Commit method of a transaction and an exception occurs during the commit process?
- The transaction is committed, and the changes are persisted in the database.
- The transaction is partially committed, leaving the database in an inconsistent state.
- The transaction is rolled back.
- The transaction remains in a pending state until the exception is resolved.
If an exception occurs during the commit process after calling the Commit method of a transaction, the transaction is rolled back to maintain data integrity. This ensures that either all changes are successfully committed, or none of them are.
When working with a Dataset, what does the AcceptChanges method do?
- Commits all changes made to the dataset since it was loaded or since the last AcceptChanges call
- Rolls back all changes made to the dataset since it was loaded or since the last AcceptChanges call
- Marks all rows in the dataset as deleted
- Adds a new row to the dataset
The AcceptChanges method in ADO.NET commits all changes made to the dataset since it was loaded or since the last AcceptChanges call. This means that any changes to the data become permanent and cannot be rolled back. The other options do not accurately describe the purpose of the AcceptChanges method.