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Questions and Answers
What is the primary purpose of ADO.NET in .NET applications?
Which type of exception is thrown by the .NET runtime?
What is the term for hiding internal implementation details in object-oriented programming?
What is the purpose of the Finally block in a Try-Catch-Finally statement?
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What is the term for creating a new class based on an existing one in object-oriented programming?
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What is the purpose of encapsulation in object-oriented programming?
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In ADO.NET, a DataReader is used to update data in a database.
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What is the term for the ability of an object to take on multiple forms in object-oriented programming?
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In ADO.NET, a _______________________ is used to execute a SQL query or stored procedure.
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Match the following ADO.NET components with their descriptions:
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In exception handling, a Try block is used to handle exceptions.
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What is the purpose of a Finally block in a Try-Catch-Finally statement?
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What is the base class for custom exceptions in .NET?
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In object-oriented programming, a _______________________ is an instance of a class.
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In exception handling, it is a best practice to catch general exceptions rather than specific exceptions.
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Study Notes
ADO.NET
- ADO.NET (ActiveX Data Objects .NET) is a set of classes that provide data access services to .NET applications
- Allows connection to various data sources such as databases, files, and XML data
- Consists of two main components:
-
Connected Data Access: uses
ConnectionandCommandobjects to interact with data sources -
Disconnected Data Access: uses
DataSetandDataTableobjects to store and manipulate data in memory
-
Connected Data Access: uses
Exception Handling
- Exception handling is a mechanism to handle runtime errors in VB.NET
-
Try-Catch-Finally block:
- Try: code that may throw an exception
- Catch: code to handle the exception
- Finally: code to execute regardless of whether an exception was thrown
- Types of exceptions:
- SystemException: exceptions thrown by the .NET runtime
- ApplicationException: exceptions thrown by the application
- Throw keyword: used to rethrow an exception or throw a new one
- Try-Catch block can be nested to handle different types of exceptions
Object-oriented Programming (OOP)
- OOP principles:
- Encapsulation: hiding internal implementation details
- Abstraction: showing only necessary information
- Inheritance: creating a new class based on an existing one
- Polymorphism: multiple forms of a class or method
-
Class:
- A blueprint for creating objects
- Can contain properties, methods, and events
-
Object:
- An instance of a class
- Has its own set of attributes (data) and methods
-
Inheritance:
- Base Class: the class being inherited from
- Derived Class: the class that inherits from the base class
- MustInherit: keyword to indicate a class cannot be instantiated
-
Polymorphism:
- Overloading: multiple methods with the same name but different parameters
- Overriding: a derived class provides a different implementation of a method
ADO.NET
- ADO.NET is a set of classes that provide data access services to .NET applications
- Enables connection to various data sources such as databases, files, and XML data
- Comprises two main components:
-
Connected Data Access: utilizes
ConnectionandCommandobjects to interact with data sources -
Disconnected Data Access: utilizes
DataSetandDataTableobjects to store and manipulate data in memory
-
Connected Data Access: utilizes
Exception Handling
- Exception handling is a mechanism to handle runtime errors in VB.NET
-
Try-Catch-Finally block:
- Try: code that may throw an exception
- Catch: code to handle the exception
- Finally: code to execute regardless of whether an exception was thrown
- SystemException: exceptions thrown by the .NET runtime
- ApplicationException: exceptions thrown by the application
- Throw keyword: used to rethrow an exception or throw a new one
- Try-Catch block can be nested to handle different types of exceptions
Object-oriented Programming (OOP)
- Encapsulation: hiding internal implementation details
- Abstraction: showing only necessary information
- Inheritance: creating a new class based on an existing one
- Polymorphism: multiple forms of a class or method
- Class: a blueprint for creating objects
- Object: an instance of a class with its own set of attributes (data) and methods
-
Inheritance:
- Base Class: the class being inherited from
- Derived Class: the class that inherits from the base class
- MustInherit: keyword to indicate a class cannot be instantiated
-
Polymorphism:
- Overloading: multiple methods with the same name but different parameters
- Overriding: a derived class provides a different implementation of a method
Object-Oriented Programming (OOP)
- Classes define properties and behavior, while objects are instances of classes with their own state and behavior
- Classes act as blueprints for creating objects
- Objects can be thought of as instances of classes
Inheritance
- Inheritance allows a child class to inherit properties and behavior from a parent class (also known as the base class)
- Child classes can build upon the properties and behavior of parent classes
- Inheritance enables code reuse and facilitates a more hierarchical organization of code
Polymorphism
- Polymorphism enables objects to take on multiple forms
- Method overriding allows for providing a different implementation for a method
- Method overloading allows for providing multiple definitions for a method
- Polymorphism enhances flexibility and modularity in programming
Encapsulation
- Encapsulation involves hiding internal implementation details from the outside world
- Encapsulation promotes information hiding and abstraction
- Public methods and properties are used to expose only necessary information
Abstraction
- Abstraction involves focusing on essential features and hiding non-essential details
- Abstraction enables defining an interface or abstract class to provide a contract
- Abstraction facilitates modular and reusable code
ADO.NET
ADO.NET Components
- Connection establishes a connection to a database
- Command executes a SQL query or stored procedure
- DataReader retrieves data from a database in a read-only, forward-only stream
- DataAdapter fills a DataSet with data from a database and updates the database
DataSet
- DataSet is an in-memory representation of data
- DataSet can be used to store and manipulate data locally
- DataSet can be updated and synchronized with a database
Data Binding
- Data binding involves binding data to a control or component
- Data binding automatically updates the control when the data changes
- Data binding facilitates a loose coupling between data and its presentation
Exception Handling
Try-Catch Blocks
- Try block contains code that may throw an exception
- Catch block contains code that handles the exception
- Finally block contains code that runs regardless of whether an exception was thrown
Exception Types
- System.Exception is the base class for all exceptions
- ApplicationException is the base class for custom exceptions
- Specific exceptions (e.g., SqlException, IOException) inherit from these base classes
Throwing Exceptions
- The Throw keyword is used to manually throw an exception
- The Throw keyword can be used to rethrow an exception
- Throwing exceptions facilitates error handling and debugging
Best Practices
- Catch specific exceptions rather than general exceptions
- Avoid catching exceptions that cannot be handled
- Use finally blocks to release resources
- Follow best practices for exception handling to ensure robust and reliable code
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Description
Learn about the basics of ADO.NET, a data access technology for .NET applications, including connected and disconnected data access components.
