What is the primary purpose of non-query commands (INSERT, UPDATE, DELETE) in ADO.NET?
- Creating a new database.
- Establishing a connection to a database.
- Inserting data into, updating data in, or deleting data from a database.
- Retrieving data from a database.
Non-query commands in ADO.NET, such as INSERT, UPDATE, and DELETE, are primarily used for modifying data in a database. These commands allow you to insert new records into a table, update existing records, or delete records from a table. They do not return any data, hence the term "non-query."
Which ADO.NET class is commonly used to update data in a dataset?
- SqlCommand
- SqlConnection
- SqlDataAdapter
- SqlDataReader
SqlDataAdapter is commonly used to update data in a dataset in ADO.NET. It acts as a bridge between the dataset and the data source, allowing developers to fill datasets with data from the database and update the database with changes made to the dataset.
Scenario: You want to implement a feature where users can group data by a specific column in the table. Which control would be more suitable for this task, DataGrid or DataGridView, and how would you achieve it?
- DataGrid with AllowGrouping property
- DataGrid with GroupingEnabled property
- DataGridView with AllowGrouping property
- DataGridView with GroupingEnabled property
To implement a feature where users can group data by a specific column in the table, the DataGridView control with the GroupingEnabled property enabled would be more suitable. This property allows users to group data by dragging column headers to the grouping area, providing a convenient way to organize and analyze information. With DataGridView, users can easily create custom groups and expand/collapse them as needed, enhancing the data presentation capabilities of the application.
Which ADO.NET provider-specific classes allow you to define parameters differently for different database systems?
- OdbcParameter
- OleDbParameter
- OracleParameter
- SqlParameter
SqlParameter is an ADO.NET provider-specific class that allows you to define parameters differently for different database systems. It provides a way to specify parameters in a uniform manner across various database providers, such as SQL Server, Oracle, MySQL, etc. This flexibility allows developers to write database-independent code while still ensuring proper parameterization and security against SQL injection attacks.
Entity Framework supports different query execution modes, such as _______ and _______.
- Deferred Loading
- Eager Loading
- Explicit Loading
- Lazy Loading
Entity Framework provides various query execution modes to retrieve data from the database efficiently. Lazy loading delays the loading of related entities until they are explicitly accessed, reducing the initial load time. Eager loading loads related entities along with the main entity in a single query, which can improve performance by reducing the number of database round-trips. Explicit loading allows developers to selectively load related entities on demand. Deferred loading, also known as delayed loading, defers the loading of related entities until they are accessed for the first time, which can enhance performance by fetching only the necessary data when needed.
Scenario: You need to retrieve data from an XML document. Which LINQ technology can be used for querying XML data?
- LINQ to Entities
- LINQ to Objects
- LINQ to SQL
- LINQ to XML
LINQ to XML is designed for querying and manipulating XML data. It allows developers to write LINQ queries against XML documents, providing a convenient and expressive way to extract and process XML data.
DataViews are particularly useful when you want to present a ___________ of your data to the user.
- Sorted view
- Filtered view
- Virtualized view
- Customized view
DataViews in ADO.NET are versatile tools for data manipulation. They allow you to present a customized view of your data to the user. This can include sorting, filtering, and applying custom logic to the data, hence "Customized view" is the correct option.
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.