EF Core 8 introduces the capability to execute raw SQL queries that return results as unmapped types. This feature provides flexibility in accessing data that doesn't directly map to your entity classes, enabling custom data models and specialized queries.
The following table summarizes the main concepts and features of raw SQL for unmapped types in EF Core 8:
| Concept | Description | Purpose |
|---|---|---|
| Unmapped Types | Custom data models not mapped to database tables. | Facilitate specialized queries and data transformation. |
| Raw SQL Queries | Direct SQL queries executed against the database. | Enable complex data retrieval beyond entity models. |
| Flexibility | Access and manipulate data using custom SQL. | Provide solutions for unique data access scenarios. |
| Performance | Optimize queries for specific data retrieval tasks. | Improve performance by tailoring SQL to requirements. |
Raw SQL queries for unmapped types in EF Core 8 provide a way to execute custom SQL queries and map the results to data models that are not part of your entity classes. This feature is ideal for scenarios that require flexibility in data access and manipulation.
public void ExecuteRawSqlExample()
{
var products = _context.Products
.FromSqlRaw("SELECT * FROM Products")
.ToList();
}
This example introduces the concept of raw SQL for unmapped types and its use cases in modern applications.
To use raw SQL for unmapped types, you need to define custom data models that represent the query results. These models do not need to be part of your DbContext, allowing you to create flexible and dynamic data structures.
// Defining unmapped types for raw SQL queries in EF Core 8
// Create custom data models that represent query results
public class OrderSummary
{
public int OrderId { get; set; }
public DateTime OrderDate { get; set; }
public decimal TotalAmount { get; set; }
}
This example demonstrates how to define unmapped types in an EF Core 8 application.
EF Core 8 allows you to execute raw SQL queries and map the results to unmapped types. This involves using the `FromSqlRaw` method and specifying the custom data model to receive the query results.
// Executing raw SQL queries for unmapped types in EF Core 8
// Use FromSqlRaw to execute SQL and map results to custom data models
public class ApplicationDbContext : DbContext
{
public List<OrderSummary> GetOrderSummaries()
{
return Database.SqlQuery<OrderSummary>(
"SELECT OrderId, OrderDate, SUM(TotalAmount) AS TotalAmount FROM Orders GROUP BY OrderId, OrderDate").ToList();
}
}
This example shows how to execute raw SQL queries for unmapped types in EF Core 8.
Raw SQL queries for unmapped types are particularly useful for complex data retrieval scenarios that require advanced SQL capabilities, such as joins, aggregations, and window functions. You can use raw SQL to retrieve and transform data efficiently.
// Using raw SQL for complex data retrieval in EF Core 8
// Execute advanced SQL queries for specialized data access
public class ApplicationDbContext : DbContext
{
public List<CustomerOrderSummary> GetCustomerOrderSummaries()
{
return Database.SqlQuery<CustomerOrderSummary>(
"SELECT c.CustomerId, c.CustomerName, COUNT(o.OrderId) AS OrderCount, SUM(o.TotalAmount) AS TotalSpent
FROM Customers c
JOIN Orders o ON c.CustomerId = o.CustomerId
GROUP BY c.CustomerId, c.CustomerName").ToList();
}
}
This example demonstrates how to use raw SQL for complex data retrieval in EF Core 8.
Mapping SQL results to unmapped types involves defining data models that match the query structure and specifying these models in the `FromSqlRaw` method. This allows you to easily work with the query results in your application.
// Mapping SQL results to unmapped types in EF Core 8
// Define data models that match the query structure for seamless mapping
public class CustomerOrderSummary
{
public int CustomerId { get; set; }
public string CustomerName { get; set; }
public int OrderCount { get; set; }
public decimal TotalSpent { get; set; }
}
public class ApplicationDbContext : DbContext
{
public List<CustomerOrderSummary> GetCustomerOrderSummaries()
{
return Database.SqlQuery<CustomerOrderSummary>(
"SELECT CustomerId, CustomerName, COUNT(OrderId) AS OrderCount, SUM(TotalAmount) AS TotalSpent
FROM Orders
GROUP BY CustomerId, CustomerName").ToList();
}
}
This example illustrates how to map SQL results to unmapped types in EF Core 8.
While raw SQL queries for unmapped types are typically used for data retrieval, you can also execute update statements and map the affected rows to custom data models. This involves using SQL commands for updates and mapping the results as needed.
// Handling updates with raw SQL and unmapped types in EF Core 8
// Execute update statements and map affected rows to custom data models
public class ApplicationDbContext : DbContext
{
public void UpdateProductPrices(decimal percentageIncrease)
{
Database.ExecuteSqlRaw(
"UPDATE Products SET Price = Price * {0}", 1 + (percentageIncrease / 100));
}
}
This example shows how to handle updates with raw SQL and unmapped types in EF Core 8.
EF Core 8 includes advanced features for raw SQL queries with unmapped types, such as supporting complex SQL structures and integrating with other EF Core features. These capabilities provide greater flexibility and control over how SQL data is handled.
// Advanced features of raw SQL for unmapped types in EF Core 8
// Integrate complex SQL logic with EF Core capabilities
public class ApplicationDbContext : DbContext
{
public List<ProductSalesDetail> GetProductSalesDetails(DateTime startDate, DateTime endDate)
{
return Database.SqlQuery<ProductSalesDetail>(
"SELECT p.ProductId, p.ProductName, SUM(s.Quantity) AS TotalQuantity, SUM(s.TotalPrice) AS TotalRevenue
FROM Products p
JOIN Sales s ON p.ProductId = s.ProductId
WHERE s.SaleDate BETWEEN {0} AND {1}
GROUP BY p.ProductId, p.ProductName", startDate, endDate).ToList();
}
}
This example explores advanced features of raw SQL for unmapped types available in EF Core 8.
While raw SQL for unmapped types provides flexibility, it's important to consider performance implications when using these queries in EF Core 8. Understanding how SQL data is retrieved and processed can help you optimize your application's performance.
// Performance considerations for raw SQL with unmapped types in EF Core 8
// Optimize SQL queries and data processing for efficiency
public class ApplicationDbContext : DbContext
{
public List<FastProductSummary> GetFastProductSummaries()
{
return Database.SqlQuery<FastProductSummary>(
"SELECT ProductId, SUM(Sales) AS TotalSales FROM Sales GROUP BY ProductId").ToList();
}
}
This example outlines performance considerations and optimization strategies for using raw SQL with unmapped types in EF Core 8.
Following best practices when using raw SQL with unmapped types in EF Core 8 helps ensure efficient and reliable data handling. Consider the following guidelines:
EF Core 8's support for raw SQL queries with unmapped types introduces powerful new features for handling complex data retrieval and manipulation scenarios. By executing custom SQL queries and mapping the results to data models, developers can effectively integrate raw SQL into their EF Core applications. Following best practices ensures efficient and reliable data handling, making raw SQL for unmapped types a valuable addition to EF Core 8.
Transactions are crucial when executing multiple raw SQL commands that must succeed or fail as a unit. EF Core allows you to wrap raw SQL operations in transactions to ensure data integrity and consistency.
public void ExecuteTransactionWithRawSql()
{
using (var transaction = _context.Database.BeginTransaction())
{
try
{
_context.Database.ExecuteSqlRaw("DELETE FROM Orders WHERE OrderDate < '2023-01-01'");
_context.Database.ExecuteSqlRaw("UPDATE Customers SET Status = 'Inactive' WHERE LastOrderDate < '2023-01-01'");
transaction.Commit();
}
catch
{
transaction.Rollback();
throw;
}
}
}
This example demonstrates how to handle transactions when executing raw SQL commands for unmapped types.
Debugging raw SQL queries can be challenging, especially when dealing with complex SQL logic. EF Core provides tools and strategies to help you debug and troubleshoot raw SQL queries effectively.
// Debugging raw SQL queries in EF Core 8
// Techniques for troubleshooting and optimizing SQL queries
public class ApplicationDbContext : DbContext
{
public void DebugRawSql()
{
var commandText = "SELECT * FROM Products WHERE Price > {0}";
var parameter = 100;
var results = Database.SqlQuery<Product>(commandText, parameter).ToList();
Console.WriteLine($"Executed SQL: {commandText}");
Console.WriteLine($"With Parameter: {parameter}");
Console.WriteLine($"Results: {results.Count}");
}
}
This example illustrates techniques for debugging raw SQL queries in EF Core 8.
EF Core 8 allows you to integrate raw SQL queries with other EF Core features, such as tracking and change detection. This enables seamless interaction between raw SQL results and your existing entity models.
// Integrating raw SQL with Entity Framework features in EF Core 8
// Use raw SQL results alongside EF Core's tracking and change detection
public class ApplicationDbContext : DbContext
{
public void IntegrateRawSql()
{
var sqlResults = Database.SqlQuery<Order>("SELECT * FROM Orders WHERE Status = 'Pending'").ToList();
foreach (var order in sqlResults)
{
order.Status = "Processed";
}
SaveChanges(); // Apply changes using EF Core's change tracking
}
}
This example explores how to integrate raw SQL queries with Entity Framework features in EF Core 8.
Raw SQL queries for unmapped types are useful in a variety of real-world scenarios, including reporting, data migration, and integration with external systems. Understanding these use cases can help you leverage raw SQL effectively in your applications.
// Real-world use cases for raw SQL with unmapped types in EF Core 8
// Leverage raw SQL for reporting, data migration, and external integration
public class ApplicationDbContext : DbContext
{
public List<ReportData> GenerateReport()
{
return Database.SqlQuery<ReportData>(
"SELECT Date, SUM(Amount) AS TotalAmount FROM Transactions GROUP BY Date").ToList();
}
}
This example discusses real-world use cases for raw SQL with unmapped types in EF Core 8.
Security is a critical concern when using raw SQL queries, especially in web applications. EF Core provides mechanisms to help you secure your raw SQL operations and protect against SQL injection and other attacks.
// Security considerations for raw SQL queries in EF Core 8
// Implement strategies to secure SQL operations and prevent injection attacks
public class ApplicationDbContext : DbContext
{
public List<Product> GetSecureProducts(string category)
{
return Database.SqlQuery<Product>(
"SELECT * FROM Products WHERE Category = {0}", category).ToList();
}
}
This example highlights security considerations and strategies for securing raw SQL queries in EF Core 8.
As EF Core continues to evolve, future versions may introduce additional enhancements for raw SQL queries, further expanding their capabilities and use cases. Keeping abreast of these developments can help you take full advantage of EF Core's raw SQL features.
// Future enhancements for raw SQL in EF Core
// Explore potential new features and improvements in upcoming EF Core versions
public class ApplicationDbContext : DbContext
{
public List<FutureProductData> GetFutureProductData()
{
// Example placeholder for future SQL enhancements
return Database.SqlQuery<FutureProductData>("SELECT * FROM FutureProducts").ToList();
}
}
This example discusses potential future enhancements in EF Core for raw SQL queries with unmapped types.