DimonSmart.Specification
1.0.7
Prefix Reserved
dotnet add package DimonSmart.Specification --version 1.0.7
NuGet\Install-Package DimonSmart.Specification -Version 1.0.7
<PackageReference Include="DimonSmart.Specification" Version="1.0.7" />
paket add DimonSmart.Specification --version 1.0.7
#r "nuget: DimonSmart.Specification, 1.0.7"
// Install DimonSmart.Specification as a Cake Addin #addin nuget:?package=DimonSmart.Specification&version=1.0.7 // Install DimonSmart.Specification as a Cake Tool #tool nuget:?package=DimonSmart.Specification&version=1.0.7
Specification Pattern Implementation in C#
Overview
The Specification Pattern is a behavioral design pattern that allows you to define reusable and composable query specifications. It is commonly used in scenarios where you need to filter, order, and include related entities in a query. The main idea behind this pattern is to encapsulate the logic of a query into separate specification classes, which can then be combined and reused to build complex queries.
In this C# implementation of the Specification Pattern, we have two parts:
1. Classical Specification (Specification class)
The classical specification provides the core functionality to build query specifications. It contains methods to define filtering criteria (Where), sorting (OrderBy, OrderByDesc), and logical operations (And, Or) to combine multiple specifications together.
Usage Example:
var specification = Specification<Student>
.Create()
.Where(s => s.Age < 21)
.OrderBy(s => s.Name)
.OrderByDesc(s => s.Age);
2. Specification for use with EntityFrameworkCore (EFCoreSpecification)
The EntityFrameworkCore support extends the classical specification with EF-specific operations, such as Include and ThenInclude, to eagerly load related entities in the query.
Usage Example:
var specification = EFCoreSpecification<Student>
.Create()
.Where(s => s.Age < 21)
.Include(s => s.School.MainBook.Author);
Executing Specifications
To execute the specifications, you can use extension methods on the DBContext provided.
var under21 = _testDBContext.BySpecification(specification).ToList();
Custom Specifications
Developers can create their custom specification classes by inheriting
from the Specification<TEntity>
class and pass parameters through
the constructor.
Example:
public class CustomStudentSpecification : Specification<Student>
{
public CustomStudentSpecification(int minAge, string schoolName)
{
Where(s => s.Age >= minAge && s.School.Name == schoolName);
}
}
Conclusion
The Specification Pattern in C# allows you to create reusable and composable query specifications for different data access scenarios. By providing EntityFrameworkCore support, you can efficiently use these specifications in Entity Framework queries, enhancing query performance and readability.
Remember that you can also create custom specification classes by inheriting from the base Specification class, making the pattern even more flexible and adaptable to various business requirements.
Supported functions
Where(Expression<Func<T, bool>> expr)
Specifies a filtering condition for the data query.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.Where(s => s.Age < 21);
OrderBy(Expression<Func<T, object>> orderByExpression)
Specifies an ascending order for the data query.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.OrderBy(s => s.Name);
OrderByDesc(Expression<Func<T, object>> orderByExpression)
Specifies an ascending order for the data query
Example:
var specification = EFCoreSpecification<Student>
.Create()
.OrderByDesc(s => s.Name);
Take(int take)
Specifies the number of elements to be skipped from the query.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.Take(10);
Skip(int skip)
Specifies the number of elements to be skipped from the query.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.Skip(20);
Include(Expression<Func<T, TProperty>> includeExpression) / ThenInclude
Adds an "Include" statement to the query, specifying related entities to be loaded.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.Include(s => s.Orders)
.ThenInclude(order => order.OrderDetails);
AsNoTracking()
AsNoTracking specifies that the query should be executed with "NoTracking" behavior.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.AsNoTracking();
AsNoTrackingWithIdentityResolution()
AsNoTrackingWithIdentityResolution specifies that the query should be executed with "NoTracking" and identity resolution behavior.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.AsNoTrackingWithIdentityResolution();
AsSplitQuery()
AsSplitQuery specifies that the query should be executed with "SplitQuery" behavior.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.AsSplitQuery();
AsSingleQuery()
AsSingleQuery Specifies that the query should be executed with "SingleQuery" behavior.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.AsSingleQuery();
IgnoreAutoIncludes()
IgnoreAutoIncludes specifies to ignore automatically included related entities in the query.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.IgnoreAutoIncludes();
IgnoreQueryFilters()
IgnoreQueryFilters specifies to ignore query filters defined in the model.
Example:
var specification = EFCoreSpecification<Student>
.Create()
.IgnoreQueryFilters();
Or(IEFCoreSpecification<T> or)
Combines the current specification with another specification using the logical OR operator.
Example:
var youngStudentsSpec = EFCoreSpecification<Student>
.Create()
.Where(s => s.Age < 21);
var studentsFromNewYorkSpec = EFCoreSpecification<Student>
.Create()
.Where(s => s.City == "New York");
var combinedSpecificationWithOr = youngStudentsSpec.Or(studentsFromNewYorkSpec);
And(IEFCoreSpecification<T> and)
Combines the current specification with another specification using the logical AND operator.
Example:
var youngStudentsSpec = EFCoreSpecification<Student>
.Create()
.Where(s => s.Age < 21);
var studentsFromNewYorkSpec = EFCoreSpecification<Student>
.Create()
.Where(s => s.City == "New York");
var combinedSpecificationWithAnd = youngStudentsSpec.And(studentsFromNewYorkSpec);
Product | Versions Compatible and additional computed target framework versions. |
---|---|
.NET | net6.0 is compatible. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 was computed. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 was computed. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. |
-
net6.0
- Microsoft.EntityFrameworkCore.Relational (>= 7.0.10)
NuGet packages (1)
Showing the top 1 NuGet packages that depend on DimonSmart.Specification:
Package | Downloads |
---|---|
DimonSmart.Specification.EntityFrameworkCore
EFSpecification: Simplify querying with the Specification pattern in Entity Framework Core. Build expressive, composable, and reusable query specifications to enhance your application's data retrieval capabilities effortlessly. Enjoy! |
GitHub repositories
This package is not used by any popular GitHub repositories.