README_DotNet.md

GraphQl.EfCore.Translate.DotNet

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Start

Install

Install the package

Install-Package GraphQl.EfCore.Translate.DotNet

Connect services in Startup.cs file

using GraphQl.EfCore.Translate.DotNet;

public void ConfigureServices(IServiceCollection services)
{
    ...
    services.AddEFCoreGraphQLDotNet();
    /*
      Or

      services.AddSingleton<GraphQl.EfCore.Translate.DotNet.StringComparisonGraph>();
      services.AddSingleton<GraphQl.EfCore.Translate.DotNet.WhereExpressionGraph>();
      services.AddSingleton<GraphQl.EfCore.Translate.DotNet.ComparisonGraph>();
      services.AddSingleton<GraphQl.EfCore.Translate.DotNet.ConnectorGraph>();
    */
    ...
}

Usage

using GraphQl.EfCore.Translate.DotNet;

...

Field<ListGraphType<StudentObject>, List<Student>>("students")
  .Argument<IntGraphType>("take")
  .Argument<IntGraphType>("skip")
  .Argument<StringGraphType>("orderBy")
  .Argument<ListGraphType<WhereExpressionGraph>>("where")
  .Resolve().WithScope().WithService<SchoolContext>()
  .ResolveAsync((context, dbContext) =>
  {
    var query = dbContext.Students.GraphQl(context);
    // Or
    /* var query = dbContext.Students
                              .GraphQlWhere(context)
                              .GraphQlOrder(context)
                              .GraphQlPagination(context)
                              .GraphQlSelect(context); */

    return query.ToListAsync();
  });

Now you can run a simple GraphQL query. We will get the first 30 students and in the linked data we will only take courses with "Calculus".

The fields "CalculatedField" and "CalculatedField2" are calculated fields from the example in the repository. "CalculatedField" is a constant, so it will not be present in the SQL query.

query {
  students(
    take: 30,
    orderBy: "enrollmentDate desc",
    where: [
      {
        "Path": "enrollmentDate", "Comparison": "LESS_THAN_OR_EQUAL", "Value": "2005-01-01"
      }
    ]
  ) {
    ID
    LastName
    CalculatedField
    CalculatedField2
    EnrollmentDate
    Enrollments(
      orderBy: "grade, course.title",
      where: [
        {
          Path: "Course.Title", Value: "Calculus"
        }
      ]
    ) {
      Grade
      Course {
        Title
        Test
      }
    }
  }
}

This query will be equivalent to the following expression

SELECT t."ID", t."LastName", t.c, t."EnrollmentDate", t0."Grade", t0.c, t0."Title", t0."EnrollmentID", t0."CourseID"
FROM (
    SELECT s."ID", s."LastName", (
        SELECT COUNT(*)::INT
        FROM "Enrollments" AS e
        WHERE (s."ID" = e."StudentID") AND (e."Grade" = 0)) AS c, s."EnrollmentDate"
    FROM "Students" AS s
    WHERE s."EnrollmentDate" <= TIMESTAMPTZ '2005-01-01 00:00:00Z'
    ORDER BY s."EnrollmentDate" DESC
    LIMIT @__p_1 OFFSET @__p_0
) AS t
LEFT JOIN (
    SELECT e0."Grade", FALSE AS c, c."Title", e0."EnrollmentID", c."CourseID", e0."StudentID"
    FROM "Enrollments" AS e0
    INNER JOIN "Courses" AS c ON e0."CourseID" = c."CourseID"
    WHERE c."Title" = 'Calculus'
) AS t0 ON t."ID" = t0."StudentID"
ORDER BY t."EnrollmentDate" DESC, t."ID", t0."Grade", t0."Title", t0."EnrollmentID"