⚠ Note: This library is intended for educational and demonstration purposes only. While it works as expected, it still requires further refinement for real-world use, especially in terms of usability.

Ideally, the API should be as intuitive as libraries like Entity Framework Plus. However, achieving this level of simplicity required careful consideration regarding thread safety. The current implementation is fully thread-safe, even when the same DeferredContext is accessed across multiple threads—though this may still depend on the specific use case.

Overview

This lightweight .NET 6+ library, compatible with Entity Framework Core, enables querying multiple datasets in a single database round trip. By reducing unnecessary database calls, it helps mitigate performance issues where multiple queries can be executed together.

Installation & Usage

To use this library, simply add the project as a reference in your application.

Example Usage

var context = new DeferredContext("<your-super-secret-connection-string>");

var older_than_thirty_employees = context.Future(m_DbContext.Employees.Where(i => i.Age >= 30));

var total_invoice_amount = context.FutureSum(
    m_DbContext.Invoices.Where(i => i.CreationTime >= DateTime.Now.AddDays(-1)), 
    i => i.InvoiceAmount
);

var late_employees = context.FutureFirstOrDefault(
    m_DbContext.Employees
        .Include(i => i.AttendanceEntries)
        .Where(i => i.AttendanceEntries.Any(i => i.Type == AttendanceTypeEnum.Late))
);

// Execute all queries in a single round trip
await context.ExecuteAsync();

After calling await context.ExecuteAsync();, all the variables (older_than_thirty_employees, total_invoice_amount, late_employees) will be populated with their respective results.

• If the result set contains multiple items, you can access them via .Items.
• If the result is a single value, use .Value.

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Supported Future Methods

This library provides the following deferred execution methods for batching multiple queries:

Method	Return Type
.FutureSum()	int or int?
.FutureSum()	long or long?
.FutureCount()	int
.FutureLongCount()	long
.FutureSkip()	T[]
.FutureTake()	T[]
.FutureFirstOrDefault()	T?

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This approach makes querying multiple datasets in a single database round trip simpler, more efficient, and performance-friendly. 🚀