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Head toentitygraphql.github.io for documentation and to get started.

EntityGraphQL is a .NET library that allows you to easily build aGraphQL API on top of your data model with the extensibility to easily bring multiple data sources together in the single GraphQL schema.

EntityGraphQL builds a GraphQL schema that maps to .NET objects. It provides the functionality to parse a GraphQL query document and execute that against your mapped objects. These objects can be an Entity FrameworkDbContext or any other .NET object, it doesn't matter.

A core feature of EntityGraphQLwith Entity Framework (although EF is not a requirement) is that it builds selections of only the fields requested in the GraphQL query which means Entity Framework is not returning all columns from a table. This is done with theLINQ projection operatorSelect() hence it works across any object tree.

Please explore, give feedback or join the development.

TheEntityGraphQL.AspNet package will get you easily set up with ASP.NET.

However the coreEntityGraphQL package has no ASP.NET dependency.

Note: There is no dependency on EF. Queries are compiled toIQueryable orIEnumberable linq expressions. EF is not a requirement - any ORM working withLinqProvider or an in-memory object will work - although EF well is tested.

publicclassDemoContext:DbContext{publicDbSet<Property>Properties{get;set;}publicDbSet<PropertyType>PropertyTypes{get;set;}publicDbSet<Location>Locations{get;set;}}publicclassProperty{publicuintId{get;set;}publicstringName{get;set;}publicPropertyTypeType{get;set;}publicLocationLocation{get;set;}}publicclassPropertyType{publicuintId{get;set;}publicstringName{get;set;}publicdecimalPremium{get;set;}}publicclassLocation{publicuintId{get;set;}publicstringName{get;set;}}

Here is an example for a ASP.NET. You will also need to install EntityGraphQL.AspNet to useMapGraphQL. You can also build you own endpoint, see docs.

usingEntityGraphQL.AspNet;varbuilder=WebApplication.CreateBuilder(args);builder.Services.AddDbContext<DemoContext>(opt=>opt.UseInMemoryDatabase("Demo"));builder.Services.AddGraphQLSchema<DemoContext>();varapp=builder.Build();app.MapGraphQL<DemoContext>();app.Run();

This sets up 1 end point:

• POST at/graphql where the body of the post is a GraphQL query
• You can authorize that route how you would any ASP.NET route. See Authorization below for details on having parts of the schema requiring Authorization/Claims

You can now make a request to your API. For example

  POST localhost:5000/graphql  {    properties { id name }  }

Will return the following result.

{"data": {"properties": [      {"id":11,"name":"My Beach Pad"      },      {"id":12,"name":"My Other Beach Pad"      }    ]  }}

Maybe you only want a specific property

  {    property(id: 11) {      id name    }  }

Will return the following result.

{"data": {"property": {"id":11,"name":"My Beach Pad"    }  }}

If you need a deeper graph or relations, just ask

  {    properties {      id      name      location {        name      }      type {        premium      }    }  }

Will return the following result.

{"data": {"properties": [      {"id":11,"name":"My Beach Pad","location": {"name":"Greece"        },"type": {"premium":1.2        }      },      {"id":12,"name":"My Other Beach Pad","location": {"name":"Spain"        },"type": {"premium":1.25        }      }    ]  }}

Visitdocumentation for more information.

Lets say you have a screen in your application listing properties that can be configured per customer or user to only show exactly what they are interested in. Instead of having a bunch of checkboxes and complex radio buttons etc. you can allow a simple EQL statement to configure the results shown. Or use those UI components to build the query.

// This might be a configured EQL statement for filtering the results. It has a context of Property(type.id=2) or(type.id=3) and type.name="Farm"

This would compile to(Property p) => (p.Type.Id == 2 || p.Type.Id == 3) && p.Type.Name == "Farm";

This can then be used in various Linq functions either in memory or against an ORM.

// we create a schema provider to compile the statement against our Property typevarschemaProvider=SchemaBuilder.FromObject<Property>();varcompiledResult=EntityQueryCompiler.Compile(myConfigurationEqlStatement,schemaProvider);// you get your list of Properties from you DBvarthingsToShow=myProperties.Where(compiledResult.LambdaExpression);

Another example is you want a customised calculated field. You can execute a compiled result passing in an instance of the context type.

// You'd take this from some configurationvareql=@"if location.name = ""Mars"" then (cost + 5) * type.premium else (cost * type.premium) / 3"varcompiledResult=EntityQueryCompiler.Compile(eql,schemaProvider);vartheRealPrice=compiledResult.Execute<decimal>(myPropertyInstance);

We do our best to followSemantic Versioning:

Given a version numberMAJOR.MINOR.PATCH, an increment in:

• MAJOR version is when we make incompatible API changes,
• MINOR version is when we add functionality in a backwards compatible manner, and
• PATCH version is when we make backwards compatible bug fixes.

Please do. Pull requests are very welcome. See the open issues for bugs or features that would be useful.