You need to ensure that a database transaction is rolled back if an exception occurs during an operation. Which ADO.NET construct should you use for this purpose?
- Data Reader
- Data Set
- TransactionScope
- Try-Catch Block
In ADO.NET, you can ensure that a database transaction is rolled back if an exception occurs during an operation by using a Try-Catch Block. Within the Try block, you initiate the transaction, perform database operations, and commit the transaction if successful. In case of an exception, control passes to the Catch block where you can handle the exception and roll back the transaction to maintain data consistency and integrity.
In connection pooling, what happens to a database connection after it is closed by the application?
- The connection is returned to the connection pool
- The connection is stored in a temporary cache
- The connection is terminated permanently
- The connection remains active indefinitely
In connection pooling, after a database connection is closed by the application, it is not immediately terminated. Instead, the connection is returned to the connection pool, where it can be reused by subsequent requests. This allows for efficient management of database connections, reducing the overhead of establishing new connections for each database interaction.
What is the primary purpose of using parameterized queries in ADO.NET?
- To automatically generate SQL queries
- To encrypt query parameters
- To improve query performance
- To prevent SQL injection attacks
Parameterized queries in ADO.NET help prevent SQL injection attacks by separating SQL code from user input. This reduces the risk of malicious SQL code being injected into the query, enhancing the security of the application.
What is the primary purpose of data binding in WinForms applications?
- To handle user input events
- To improve the visual appearance of controls
- To manage application resources
- To synchronize data between controls and data sources
Data binding in WinForms applications allows for the synchronization of data between controls and data sources, ensuring that changes in one are reflected in the other. This simplifies the development process and enhances the maintainability of the application.
A parameterized query replaces user input in SQL statements with ________ to prevent SQL injection.
- functions
- operators
- placeholders
- variables
Parameterized queries replace user input in SQL statements with placeholders. These placeholders act as markers for where the input data should be inserted into the query. By using placeholders, the SQL engine can differentiate between executable SQL code and user-provided data, thereby preventing SQL injection attacks.
What is the purpose of the BeginTransaction method in ADO.NET?
- To begin a database transaction
- To establish a connection to the database
- To execute a SQL command
- To retrieve data from the database
The BeginTransaction method in ADO.NET is used to initiate a database transaction. It marks the beginning of a sequence of database operations that must be treated as a single unit of work, ensuring data integrity and consistency.
Which method is used to open a database connection in ADO.NET?
- Begin()
- Connect()
- Open()
- Start()
The method used to open a database connection in ADO.NET is Open(). Calling this method establishes a connection to the database specified by the connection string associated with the connection object.
In Entity Framework, what is the primary purpose of an Entity?
- Defining the structure of the database
- Modeling business entities
- Performing database operations
- Representing a table in the database
In Entity Framework, an Entity primarily represents a business object or concept, such as a customer or an order. It models the data that the application works with and typically corresponds to a table in the database. Entities in EF are used to perform CRUD (Create, Read, Update, Delete) operations on the underlying data.
Which LINQ to SQL operation is used to delete records from a database table?
- DeleteOnSubmit
- InsertOnSubmit
- RemoveOnSubmit
- UpdateOnSubmit
In LINQ to SQL, the operation used to delete records from a database table is DeleteOnSubmit. Similar to insertion and updating, deletion operations are also performed within a DataContext instance. This method queues up objects for deletion, and upon calling SubmitChanges(), the changes are applied to the underlying database. Understanding how to delete records is crucial for maintaining data integrity and managing database content effectively in LINQ to SQL applications.
When resolving a merge conflict in Git, what approach would you take to ensure the integrity of the codebase?
- Choose one side's changes without review
- Merge conflicting changes manually
- Discard conflicting changes
- Always accept remote changes
The correct option is b) Merge conflicting changes manually. This approach involves carefully reviewing and selecting the changes from both sides to create a resolution that maintains code integrity. Options a, c, and d may lead to loss of important code or introduce errors.