Advanced Data Access in .NET Framework

This section delves into more sophisticated techniques for interacting with data sources within the .NET Framework, moving beyond basic CRUD operations to explore performance optimization, complex querying, and integration with various data technologies.

Leveraging LINQ to SQL and LINQ to Entities

Language Integrated Query (LINQ) provides a powerful, unified way to query data from various sources. LINQ to SQL and LINQ to Entities allow you to query relational databases directly from your .NET code using familiar object-oriented syntax.

LINQ to SQL

LINQ to SQL maps database tables to classes and rows to objects. This facilitates seamless querying and manipulation of data.

Key Features:

Example: Fetching Customers


using System.Linq;
using System.Data.Linq;

// Assuming 'db' is an instance of your DataContext
var customers = from cust in db.Customers
                where cust.City == "London"
                select cust;

foreach (var customer in customers)
{
    Console.WriteLine($"ID: {customer.CustomerID}, Name: {customer.CompanyName}");
}

LINQ to Entities (Entity Framework)

Entity Framework is a more comprehensive ORM that provides a higher level of abstraction. LINQ to Entities queries are translated into queries for the underlying data store.

Key Benefits:

Note: While LINQ to SQL is simpler for direct table mapping, Entity Framework offers more flexibility and features for complex enterprise applications.

Optimizing Data Access Performance

Efficient data access is crucial for application performance. Advanced techniques focus on reducing the amount of data transferred and minimizing database round trips.

Batch Operations

When performing multiple insert, update, or delete operations, consider batching them to reduce network latency and database overhead. ADO.NET provides `SqlBulkCopy` for efficient bulk data loading into SQL Server.

Connection Pooling

Connection pooling is enabled by default for most data providers in .NET. It reuses database connections, significantly reducing the overhead of establishing new connections for each request.

Asynchronous Data Operations

Utilizing asynchronous programming patterns (`async`/`await`) for database operations prevents blocking the UI thread or request threads, leading to a more responsive application.

Example: Asynchronous Query


using System.Threading.Tasks;
using System.Data.SqlClient;

public async Task<List<string>> GetProductNamesAsync(string connectionString)
{
    var productNames = new List<string>();
    using (var connection = new SqlConnection(connectionString))
    {
        await connection.OpenAsync();
        var command = new SqlCommand("SELECT Name FROM Products", connection);
        using (var reader = await command.ExecuteReaderAsync())
        {
            while (await reader.ReadAsync())
            {
                productNames.Add(reader.GetString(0));
            }
        }
    }
    return productNames;
}

Working with Stored Procedures and Functions

Stored procedures and functions can encapsulate business logic directly within the database, offering benefits like reusability, performance, and security.

Executing Stored Procedures

ADO.NET allows you to easily execute stored procedures using `SqlCommand` by setting the `CommandType` to `StoredProcedure`.

Passing Parameters

Properly handling parameters, including output parameters and return values, is essential when working with stored procedures.

Tip: Use `SqlParameter` objects to add parameters to your `SqlCommand` to prevent SQL injection vulnerabilities.

Advanced Topics

Important: Always validate and sanitize user input before using it in database queries to prevent security breaches.