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.
To enable connection pooling, you need to set the "Pooling" attribute in the connection string to ___________.
- FALSE
- No
- TRUE
- Yes
The "Pooling" attribute in the connection string should be set to "True" to enable connection pooling. This allows the .NET framework to manage connection pooling efficiently.
In LINQ to Objects, is it possible to query in-memory collections like arrays and lists?
- Depends on the Collection Size
- No
- Sometimes
- Yes
Yes, LINQ to Objects enables querying in-memory collections such as arrays and lists. It provides a powerful and convenient way to manipulate data structures within the application's memory, offering functionalities like filtering, sorting, and projecting data from these collections.
Which namespace is commonly used for LINQ in C#?
- System.Collections
- System.Data
- System.Linq
- System.Xml
The System.Linq namespace is commonly used for LINQ in C#. It contains classes and interfaces that support LINQ query operations for various data sources such as collections, arrays, XML, and databases.
To add a new row to a DataTable, you can use the ___________ method.
- AddNewRow()
- CreateRow()
- InsertRow()
- NewRow()
The NewRow() method of the DataTable class is used to create a new DataRow with the same schema as the DataTable. This method creates a new DataRow instance but does not add it to the DataRow collection. It simply returns a reference to the new DataRow, which you can then manipulate and add to the DataTable using the Add() method.
In ADO.NET, how can you handle multiple result sets returned by a SELECT statement?
- Using the SqlCommand.ExecuteReader() method
- Using the SqlConnection.Open() method
- Using the SqlDataAdapter.Fill() method
- Using the SqlDataReader.NextResult() method
In ADO.NET, you can handle multiple result sets returned by a SELECT statement using the SqlDataReader.NextResult() method. This method advances the SqlDataReader to the next result set if available. It allows you to iterate through multiple result sets returned by the same command execution.
When using Oracle databases, you would use the ___________ class as a command object.
- OracleCommand
- SqlCommand
- DbCommand
- OleDbCommand
The correct option is OracleCommand. When working with Oracle databases in .NET applications, the OracleCommand class is specifically designed to execute commands against an Oracle database. It provides methods and properties to facilitate database interactions, making it the appropriate choice as a command object for Oracle databases.
LINQ queries are often used for data manipulation and transformation, which contributes to ___________ code readability.
- Increased
- Decreased
- Improved
- Simplified
LINQ provides a concise and expressive syntax for querying and manipulating data, leading to improved code readability. It simplifies complex operations like filtering, sorting, and grouping, thereby making code more understandable and maintainable. Hence, the correct option is "Improved."