Which method is typically used to add a new row of data to a DataTable in a dataset?
- AddNew()
- NewRow()
- InsertRow()
- CreateRow()
The correct option is NewRow(). This method is used to create a new DataRow object with the same schema as the DataTable but without adding it to the table. It is commonly used to prepare a new row for insertion into the DataTable. The AddNew() method is used in BindingSource to add a new row, InsertRow() and CreateRow() are not valid methods in ADO.NET.
What are DataGrid and DataGridView controls primarily used for?
- Displaying tabular data
- Drawing shapes
- Playing audio files
- Running scripts
DataGrid and DataGridView controls are primarily used for displaying tabular data in a grid format. They allow users to view and interact with data from various data sources such as databases or collections.
What is the purpose of the SelectCommand property in a DataAdapter?
- It specifies the SQL command to retrieve data from the database
- It specifies the database connection string
- It specifies the name of the database table to work with
- It specifies the primary key of the database table
The SelectCommand property of a DataAdapter is used to specify the SQL command that retrieves data from the database. This command is executed when the DataAdapter's Fill method is called to populate the DataSet with data.
In LINQ, the into keyword is used for creating ___________ queries.
- Combined
- Conditional
- Grouped
- Nested
The into keyword in LINQ is used for creating grouped queries. It is typically used in conjunction with the group clause to group the results of a query based on a specified key. This allows for aggregating or further processing the grouped data within the query.
The ___________ class is responsible for managing the database schema in LINQ to Entities.
- DbContext
- EntityModel
- EntityContext
- DataSchema
The correct option is "DbContext". In LINQ to Entities, the DbContext class is responsible for managing the database schema. It represents a session with the database and allows querying and saving data. The DbContext class is part of the Entity Framework and provides an abstraction over the database, allowing developers to work with entity objects rather than dealing directly with database connections and commands.
In ADO.NET, what is the purpose of a DataRelation?
- Deletes a record from the database
- Establishes a relationship between two tables in a DataSet
- Provides a connection string to the database
- Retrieves data from a stored procedure
A DataRelation in ADO.NET is used to establish a relationship between two tables in a DataSet. This allows for navigating between related rows and enforcing referential integrity between them. It does not provide a connection string, retrieve data from a stored procedure, or perform deletions.
What is the significance of the "ToList()" method in LINQ to Entities?
- Applies sorting to query results
- Converts query results to a List
collection - Executes the query against the database
- Retrieves the first element of the query results
The "ToList()" method in LINQ to Entities converts the query results to a List collection. It forces immediate execution of the query against the database and materializes the results into memory as a list. This can be useful when you need to manipulate or iterate over the query results multiple times without re-executing the query.
Which event is triggered when a user selects a row in a DataGrid or DataGridView control?
- CellValueChanged
- RowEnter
- RowHeaderMouseClick
- RowSelected
The "RowEnter" event is triggered when a user selects a row in a DataGrid or DataGridView control. This event occurs when the focus moves to a new row, indicating that the user has selected that row. It provides an opportunity to perform actions based on the selected row, such as retrieving data or updating other controls.
Scenario: You are developing a WinForms application that needs to display a list of products from a database. Which control and data binding method would you use to achieve this?
- DataGridView with DataSource property
- ListBox with DataBinding event
- ComboBox with DisplayMember property
- DataGrid with Bind method
The correct option is DataGridView with DataSource property. DataGridView is a versatile control for displaying tabular data and supports data binding through its DataSource property, which allows you to easily bind it to a data source such as a DataTable or a list of objects. This control provides rich functionality for displaying and editing data in a grid format, making it suitable for displaying a list of products from a database.
Your application involves updating records across different databases. How would you implement distributed transaction management in ADO.NET?
- Data Reader
- OleDbConnection
- SqlCommand
- TransactionScope
Distributed transaction management in ADO.NET can be implemented using TransactionScope. TransactionScope provides a simple and efficient way to manage distributed transactions across multiple databases or resource managers. It automatically handles enlisting connections in the transaction and ensures that either all operations across different databases succeed or fail together, maintaining data integrity and consistency.
What are some common list controls used in ADO.NET for data binding purposes?
- ListBox
- DropDownList
- ComboBox
- RadioButtonList
In ADO.NET, common list controls used for data binding include ListBox, DropDownList, ComboBox, and RadioButtonList. These controls facilitate displaying data retrieved from a data source, providing users with options to select or interact with the data displayed. DropDownList, specifically, is commonly used for displaying a list of items where users can select one option.
The ExecuteNonQuery method of a command object is typically used for executing _______ SQL commands.
- Insert
- Non-Query
- Select
- Update
The ExecuteNonQuery method is used to execute SQL commands that do not return data, such as INSERT, UPDATE, DELETE, or any SQL command that does not return a result set. It is commonly used for executing data manipulation language (DML) statements.