转换 IQueryable<t> 列出<t>将 EF 核心与 postgres 数据库一起使用</t></t>

Question

I am using a postgres DB and EF core. I have the following code get data using DB context

IQueryable<string> projectIds = context.Projects.Where(x => x.Collaborators.Contains(userId)).Select(x => x.Id);
List<string> ids = projectIds.ToList();

When I execute projectIds.ToList() , I get the exception (copied below).

What is the right way of using IQueryable? Or is there any other way to convert IQueryable to List?

Any suggestions would help a lot..

Exception details:

  HResult=0x80004005
  Message=42883: operator does not exist: character varying[] @> text[]
  Source=Npgsql
  StackTrace:
   at Npgsql.NpgsqlConnector.<<ReadMessage>g__ReadMessageLong|194_0>d.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at Npgsql.NpgsqlDataReader.<NextResult>d__44.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Npgsql.NpgsqlDataReader.NextResult()
   at Npgsql.NpgsqlCommand.<ExecuteReader>d__100.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Npgsql.NpgsqlCommand.<ExecuteReader>d__100.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Runtime.CompilerServices.ValueTaskAwaiter`1.GetResult()
   at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior)
   at Npgsql.NpgsqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader()
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.Enumerator.InitializeReader(DbContext _, Boolean result)
   at Npgsql.EntityFrameworkCore.PostgreSQL.Storage.Internal.NpgsqlExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.Enumerator.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)```

Answer 1

Thanks for all the suggestions in comments. After hours of trial found out that the error was not during converting to ToList().

The error lies with using contains operator on Character varying[]

[Not sure, if it is any kind of bug]

Modifying the Character varying[] array to text[] in postgres fixed the issue.