Scenario: Your WinForms application requires the user to edit and save customer information. How can you ensure that changes made in a data-bound control are propagated back to the data source?
- Implement the INotifyPropertyChanged interface
- Use the DataBindingComplete event
- Call the Update method of the data adapter
- Set the DataPropertyName property of the data-bound control
The correct option is Call the Update method of the data adapter. When working with data-bound controls in WinForms applications, changes made in the controls need to be saved back to the underlying data source. One way to achieve this is by calling the Update method of the data adapter associated with the data source. This method applies changes made in the data-bound controls to the database.
How can parameterized queries help prevent SQL injection attacks?
- By encrypting the SQL commands
- By restricting database access
- By separating data from SQL commands
- By using complex SQL queries
Parameterized queries help prevent SQL injection attacks by separating data from SQL commands. With parameterized queries, user inputs are treated as data rather than executable commands, reducing the risk of malicious SQL injection. Parameters act as placeholders for user-supplied values, preventing attackers from injecting SQL code into the query. This practice enhances security by ensuring that user input is sanitized and properly handled, mitigating the risk of unauthorized access or data manipulation.
A stored procedure is a precompiled ___________ of SQL statements.
- collection
- grouping
- sequence
- set
A stored procedure is a precompiled sequence of SQL statements that are stored in the database and can be executed by applications. They offer advantages such as improved performance as they are precompiled and cached, reducing parsing overhead. Additionally, they provide security by controlling access to data through parameterized queries.
In ADO.NET, what are the different ways to call a stored procedure?
- Call() method, Invoke() method, ExecuteProcedure() method, Run() method
- CommandText property, ExecuteNonQuery() method, ExecuteReader() method, ExecuteScalar() method
- ExecuteNonQuery() method, ExecuteScalar() method, ExecuteReader() method, Execute() method
- ExecuteStoredProc() method, ExecuteStoredProcedure() method, ExecuteSP() method, CallStoredProc() method
In ADO.NET, you can call a stored procedure using the ExecuteNonQuery() method to execute a command that doesn't return any result set, ExecuteScalar() method to execute a command that returns a single value, and ExecuteReader() method to execute a command that returns a result set. The Execute() method can also be used to execute any type of command.
Scenario: You are working on a project that involves querying a list of products based on their category. Which LINQ operator would you use to accomplish this task?
- Select
- Where
- OrderBy
- GroupBy
The correct option for querying a list of products based on their category is the Where operator. The Where operator is used to filter elements based on a specified condition, allowing you to retrieve only the products that belong to a specific category.
SQL injection attacks occur when malicious users exploit vulnerabilities in ___________ statements.
- DELETE
- INSERT
- SELECT
- UPDATE
SQL injection attacks occur when attackers manipulate the input of SQL queries to execute arbitrary commands. The vulnerability often lies in poorly sanitized user inputs, especially in SELECT statements, allowing unauthorized access to data.
A SqlDataReader provides a forward-only, ___________ way to read data from a database.
- Bidirectional
- Random Access
- Sequential
- One-way
The correct option is Option 3: Sequential. A SqlDataReader provides a forward-only, sequential way to read data from a database. It can only move in one direction, typically from the first row to the last, and cannot jump to specific rows or move backward.
What is the key difference between a SqlDataReader and an OracleDataReader?
- SqlDataReader is a class in the System.Data.SqlClient namespace, whereas OracleDataReader is a class in the System.Data.OracleClient namespace.
- SqlDataReader is forward-only, whereas OracleDataReader allows both forward and backward data access.
- SqlDataReader is specific to SQL Server databases, whereas OracleDataReader is specific to Oracle databases.
- SqlDataReader is used for reading data from XML files, whereas OracleDataReader is used for reading data from Oracle databases.
SqlDataReader and OracleDataReader are specific to their respective database systems and differ in their namespaces and database compatibility.
You are working on a project where database performance is critical. Which LINQ feature or technique would you consider using to minimize the number of database queries generated by LINQ?
- Compiled Query
- Deferred Loading
- Eager Loading
- Lazy Loading
Eager Loading: Eager loading is a technique in LINQ where related data is retrieved along with the main query. By using eager loading, you can minimize the number of database queries generated, thus improving performance by reducing round trips to the database. This ensures that all required data is loaded in a single query, enhancing efficiency in scenarios where database performance is crucial.
What is EF in the context of ADO.NET Entity Framework?
- Easy Framework
- Electronic Framework
- Entity
- Entity Framework
Entity Framework (EF) in the context of ADO.NET stands for Entity Framework. It is an ORM (Object-Relational Mapping) framework provided by Microsoft to work with relational databases. EF allows developers to work with data using domain-specific objects, eliminating the need for most of the data-access code that developers usually need to write.