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.
What does data concurrency refer to in the context of ADO.NET?
- The ability of multiple users to access and manipulate the same data simultaneously.
- The method of securing data during transmission over a network.
- The process of ensuring data consistency within a database.
- The technique of optimizing database queries for faster performance.
Data concurrency in ADO.NET refers to the ability of multiple users to access and manipulate the same data simultaneously without interfering with each other's changes. This is important in scenarios where multiple users may be accessing and modifying data concurrently, such as in a multi-user database system.
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.
What is the purpose of the "DataSource" property in DataGrid or DataGridView controls?
- Binds the control to a data source such as a DataTable or DataSet
- Defines the font style for the control
- Sets the background color of the control
- Specifies the width of the control
The "DataSource" property is used to bind the DataGrid or DataGridView control to a data source such as a DataTable or DataSet. This allows the control to display data from the specified source. By setting this property, you establish the connection between the control and the data it should display.
In ADO.NET, how do you access child rows related to a parent row in a hierarchical dataset?
- By iterating through the child DataTable using a foreach loop
- By setting the ChildRows property of the DataRelation object
- By using the GetChildRows() method of the DataRow object
- By using the Select() method with a filter expression
The GetChildRows() method of the DataRow object is used to access child rows related to a parent row in a hierarchical dataset. It returns an array of DataRow objects representing the child rows.