LINQ provides a unified and concise way to query and manipulate ___________ data.
- Object
- Relational
- SQL
- XML
LINQ, or Language Integrated Query, allows developers to query and manipulate objects in various data sources, including objects in memory.
In ADO.NET, what is the role of a DataTable within a dataset?
- Acts as a connection manager
- Holds data retrieved from a data source
- Represents a single table of data in memory
- Stores metadata about the data structure
A DataTable within a dataset serves as an in-memory representation of a single table retrieved from a data source. It holds the actual data rows along with metadata such as column names, data types, and constraints. This allows for disconnected access to data, enabling offline manipulation and processing.
In the context of DropDownList controls, what is the purpose of the DataTextField property?
- Defines the field that will be used to identify each item in the DropDownList
- Determines the field that will be used to populate the DropDownList with data
- Sets the text color of the items in the DropDownList
- Specifies the connection string to the database
The DataTextField property of a DropDownList control is used to specify the field from the data source that will be used to populate the control with data. This property helps determine which data field will be displayed as the text for each item in the DropDownList. It's crucial for ensuring that the DropDownList accurately reflects the data retrieved from the database or another data source.
Resource management in ADO.NET includes handling of connections, ___________, and other database-related resources.
- Indexes
- Queries
- Transactions
- Views
In addition to managing connections, ADO.NET also involves handling transactions, which are sets of operations that are treated as a single unit of work. Proper transaction management ensures data integrity and consistency in the database.
In Windows Forms, the ___________ event is commonly used to update the user interface after data changes.
- DataChanged
- DataUpdated
- DataSourceChanged
- DataBindingComplete
The correct option is DataBindingComplete. This event is commonly used in Windows Forms applications to update the user interface after data changes. It occurs after a data-binding operation has finished, allowing developers to perform additional tasks or updates to the user interface based on changes to the data source.
In ADO.NET, what is the purpose of the Connection Pooling feature?
- To automatically update database schemas
- To improve security by encrypting database connections
- To manage the connections between a .NET application and a database
- To optimize network bandwidth usage
Connection Pooling in ADO.NET is used to efficiently manage database connections between a .NET application and a database server. It helps in reusing existing connections, thus reducing the overhead of opening and closing connections frequently. This improves application performance and scalability by minimizing the time spent on establishing new connections.
ADO.NET Entity Framework is an Object-Relational Mapping (ORM) tool that helps in bridging the gap between ___________ and ___________.
- Application Layer and Database Layer
- Business Logic and Presentation Layer
- C# and SQL
- Object-Oriented Programming (OOP) and Database Management Systems (DBMS)
ADO.NET Entity Framework bridges the gap between Object-Oriented Programming (OOP) and Database Management Systems (DBMS). It allows developers to work with relational data using domain-specific objects, thus enhancing productivity and reducing development time by abstracting the complexity of database interaction.
Scenario: You are working with an Oracle database and need to handle NULL values gracefully while reading data. Which method of the OracleDataReader would you use for this purpose?
- GetValue, to retrieve the value from the database without considering if it's NULL or not, thus potentially causing errors if not handled properly.
- HasRows, to check if the result set returned by the query contains any rows, which is unrelated to handling NULL values.
- IsDBNull, to check if the value retrieved from the database is NULL, allowing for proper handling of NULL values in the application logic.
- ReadNull, to explicitly read NULL values from the database, enabling better control over how they are handled in the application.
The IsDBNull method of OracleDataReader allows for seamless handling of NULL values by checking if a retrieved value is NULL before processing it further. This helps in avoiding runtime errors and ensures smooth execution of the application logic. Other methods like GetValue do not provide the same level of control over NULL values and may lead to unexpected behavior if not handled properly.
In ADO.NET, what does a Data Filter allow you to do with a DataView?
- Aggregate rows
- Filter rows
- Group rows
- Sort rows
A Data Filter in ADO.NET allows you to filter rows in a DataView based on specified criteria. This means you can display only the rows that meet certain conditions, such as those with specific values in certain columns or rows that satisfy a particular expression. Data Filters provide a way to customize the view of data and present only relevant information to the user.
Which ADO.NET class is commonly used to execute SELECT statements and retrieve data from a database?
- SqlCommand
- SqlConnection
- SqlDataAdapter
- SqlDataReader
The SqlDataAdapter class in ADO.NET is commonly used to execute SELECT statements and retrieve data from a database. It acts as a bridge between a dataset and a data source for retrieving and saving data.