Stuck on an issue?

Lightrun Answers was designed to reduce the constant googling that comes with debugging 3rd party libraries. It collects links to all the places you might be looking at while hunting down a tough bug.

And, if you’re still stuck at the end, we’re happy to hop on a call to see how we can help out.

ToQueryString parameter values with float (and maybe real?) are wrong

See original GitHub issue

It is important that these values are correct if you rely on ToQueryString (DebugView) as a troubleshooting tool.

CREATE TABLE[dbo].[FloatTable]
(      
     [Id] INT  IDENTITY   NOT NULL,  
     [Data] FLOAT NULL
 );


using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using System;
using System.Linq;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            using var nw = new NWContext();

            // Alter this value for each run
            double? testval = 4.5655d;

            nw.FloatTables.Add(new FloatTable
            {
                Data = testval,
            });

            nw.SaveChanges();

            var query = nw.FloatTables.Where(x => x.Data == testval).ToQueryString();

            var found = nw.FloatTables.SingleOrDefault(x => x.Data == testval);
        }
    }

    public partial class FloatTable
    {
        public int Id { get; set; }
        public double? Data { get; set; }
    }

    public partial class NWContext : DbContext
    {
        public NWContext()
        {
        }

        public virtual DbSet<FloatTable> FloatTables { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
                optionsBuilder.UseSqlServer("Data Source=.\\SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=True", x => x.UseNetTopologySuite())
                    .LogTo(Console.WriteLine)
                    .EnableSensitiveDataLogging();
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.ApplyConfiguration(new FloatTableConfiguration());
        }
    }

    public partial class FloatTableConfiguration : IEntityTypeConfiguration<FloatTable>
    {
        public void Configure(EntityTypeBuilder<FloatTable> entity)
        {
            entity.ToTable("FloatTable");
        }
    }
}

ToQueryString:

DECLARE @__testval_0 float = 4.5654000000000003E0;

SELECT[f].[Id], [f].[Data]
        FROM[FloatTable] AS[f]
WHERE[f].[Data] = @__testval_0

EF Core log:

Executing DbCommand[Parameters =[@__testval_0 = '4.5654'(Nullable = true)], CommandType = 'Text', CommandTimeout = '30']

SELECT TOP(2) [f].[Id], [f].[Data]
        FROM[FloatTable] AS[f]
WHERE[f].[Data] = @__testval_0

EF Core version: 6.0.3 Database provider: Microsoft.EntityFrameworkCore.SqlServer Target framework: .NET 6.0