PostgreSQL Test Error when get Hours on TimeSpan

[sasukevita]

model

	[Table(Schema="Member", Name="Table")]
	public partial class Table
	{
		[PrimaryKey, NotNull    ] public int       Id   { get; set; } // integer
		[Column,        Nullable] public DateTime? Date { get; set; } // date
		[Column,        Nullable] public TimeSpan? Time { get; set; } // time without time zone
	}

error test

var query = (from x in db.Table
                         where x.Time.Value.Hours >= 0//Npgsql.PostgresException: '42883: operator does not exist: time without time zone > integer'
                         select new
                         {
                             Output = x.Time.Value.Hours,//LinqToDB.Common.LinqToDBConvertException: 'Cannot convert value '12:34:56' to type 'System.Int32''
                         });
            var r = query.ToArray();

Environment details

linq2db version: 3.3.0
Database: PostgreSQL 12.1
.NET Framework: 4.7.2

[jogibear9988]

We need a TimeSpan Part Builder like the DatePart Builder:

linq2db/Source/LinqToDB/Sql/Sql.DateTime.cs

Line 401 in 054da1e

public static int? DatePart([SqlQueryDependent] Sql.DateParts part, [ExprParameter] DateTime? date)

and then the Expressions for all parts like here:

linq2db/Source/LinqToDB/Linq/Expressions.cs

Line 591 in 8246efe

{ M(() => DateTime.Now.Year ), N(() => L<DateTime,int> ((DateTime obj) => Sql.DatePart(Sql.DateParts.Year, obj)!.Value )) },

[ptvbnk]

@jogibear9988 @MaceWindu
Interested to contribute to this issue.
I am trying to find a way to test this on my local.

I tried searching for creating a nuget locally and then attaching the nuget to the project and test it out.
So far my search didn't yield any results.
I searched through the documentation and couldn't find anything on this.
Can you please guide me on this?

[MaceWindu]

To build nuget locally, use NuGet\PackLocal.cmd, but I'm not sure why you need to use nuget for testing.

[ptvbnk]

Is there any easy way to test without building nuget?
How can I use the linq2db assembly in another project?

[sdanyliv]

Just add linq2db.csproj to solution and add project dependecy. Also we have linq2db.playground.slnf and you can add new test by copying TestTemplate.cs

[ptvbnk]

@sdanyliv @MaceWindu

I have created a console app in .NET CORE and added this project as reference.

Main method where I am creating connection as per code given in gitpage.

static void Main(string[] args)
       {
           // create options builder
           var builder = new LinqToDbConnectionOptionsBuilder();

           // configure connection string
           builder.UsePostgreSQL("Server=PostgreSQL 12;Port=5432;Database=postgres;User Id=postgres;Password=abcd;Pooling=true;MinPoolSize=10;MaxPoolSize=100;");

           // pass configured options to data connection constructor
           using (var dc = new DataConnection(builder.Build()))
           {

           }            
       }

Error I am getting

System.InvalidOperationException
  HResult=0x80131509
  Message=Cannot load assembly Npgsql
  Source=linq2db
  StackTrace:
   at LinqToDB.DataProvider.PostgreSQL.NpgsqlProviderAdapter.GetInstance() in C:\CodeContribute\linq2db\Source\LinqToDB\DataProvider\PostgreSQL\NpgsqlProviderAdapter.cs:line 165
   at LinqToDB.DataProvider.PostgreSQL.PostgreSQLDataProvider..ctor(String name, PostgreSQLVersion version) in C:\CodeContribute\linq2db\Source\LinqToDB\DataProvider\PostgreSQL\PostgreSQLDataProvider.cs:line 22
   at LinqToDB.DataProvider.PostgreSQL.PostgreSQLTools.<>c.<.cctor>b__19_0() in C:\CodeContribute\linq2db\Source\LinqToDB\DataProvider\PostgreSQL\PostgreSQLTools.cs:line 18
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.get_Value()

  This exception was originally thrown at this call stack:
    LinqToDB.DataProvider.PostgreSQL.NpgsqlProviderAdapter.GetInstance() in NpgsqlProviderAdapter.cs
    LinqToDB.DataProvider.PostgreSQL.PostgreSQLDataProvider.PostgreSQLDataProvider(string, LinqToDB.DataProvider.PostgreSQL.PostgreSQLVersion) in PostgreSQLDataProvider.cs
    LinqToDB.DataProvider.PostgreSQL.PostgreSQLTools..cctor.AnonymousMethod__19_0() in PostgreSQLTools.cs
    System.Lazy<T>.ViaFactory(System.Threading.LazyThreadSafetyMode)
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Lazy<T>.CreateValue()
    System.Lazy<T>.Value.get()

I debugged it and found that assembly is getting as null in NpgsqlProviderAdapter.cs file

public static NpgsqlProviderAdapter GetInstance()
		{
			if (_instance == null)
				lock (_syncRoot)
					if (_instance == null)
					{
						var assembly = Tools.TryLoadAssembly(AssemblyName, null);
						if (assembly == null)
							throw new InvalidOperationException($"Cannot load assembly {AssemblyName}");

Appreciate any help in fixing this.

[MaceWindu]

Looks like you didn't added rerefence to Npgsql nuget

[ptvbnk]

@MaceWindu
I am able to run the code after adding Npgsql nuget.

I am somewhat confused with the solution proposed by @jogibear9988
I understood that we need to add similar code for TimeParts as well.
But I am not sure if I should add another class or can I do it in sql.DateTime class or any other existing class?

Also, any reference to the internal working of the code would be helpful.
I checked Contributing.md page and couldn't find any.
I am having hard time debugging through full code and trying to make sense.
Thanks.