Show database query generated by Entity Framework Core for PostgreSQL when SaveChanges() called


I have created a database first implementation of entity framework core for postgreSQL. I have tried a simple item creation and save, but am getting a syntax error. I'd like to be able to see the generated SQL statement that might give me a clue as to the issue. How can I enable this type of output when debugging? I am new to EF in general, so for answers, please be specific and clear about the requirement.

Below is my test function:

public async Task<string> FunctionHandler(string input, ILambdaContext context)

        using (var db = new loyaltyContext())
            var customer = new Customer
                BusinessPartnerId = 4332482,
                StoreJoined = "chadstone",
                CreatedDateTime = DateTime.Now,
                CustomerType = "STANDARD",
                DateOfBith = DateTime.Now.Date,
                StoreJoinedDate = DateTime.Now.Date,
                UpdatedDateTime = DateTime.Now,
                FirstName = "Joe",
                LastName = "Test",
                Gender = "M",
                OrganisationName = "Australian Pharmaceutical Industries"

            customer.Membership.Add(new Membership { BusinessPartnerId = 4332482, DateCreated = DateTime.Now, LoyaltyCustomerId = 1234, McaId = "2701000" });
            var count = db.SaveChanges();
            Console.WriteLine("${count} changes");
    catch (Exception e)

    return input?.ToUpper();

Current error:

Npgsql.PostgresException (0x80004005): 42601: syntax error at end of input

   at Npgsql.NpgsqlConnector.<>c__DisplayClass160_0.<<DoReadMessage>g__ReadMessageLong|0>d.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at Npgsql.NpgsqlConnector.<>c__DisplayClass160_0.<<DoReadMessage>g__ReadMessageLong|0>d.MoveNext() in C:\projects\npgsql\src\Npgsql\NpgsqlConnector.cs:line 973

--- End of stack trace from previous location where exception was thrown ---

   at Npgsql.NpgsqlDataReader.NextResult(Boolean async, Boolean isConsuming) in C:\projects\npgsql\src\Npgsql\NpgsqlDataReader.cs:line 407

   at Npgsql.NpgsqlDataReader.NextResult() in C:\projects\npgsql\src\Npgsql\NpgsqlDataReader.cs:line 298

   at Npgsql.NpgsqlCommand.ExecuteReaderAsync(CommandBehavior behavior, Boolean async, CancellationToken cancellationToken) in C:\projects\npgsql\src\Npgsql\NpgsqlCommand.cs:line 1195

   at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior) in C:\projects\npgsql\src\Npgsql\NpgsqlCommand.cs:line 1076

   at Npgsql.NpgsqlCommand.ExecuteReader() in C:\projects\npgsql\src\Npgsql\NpgsqlCommand.cs:line 1067

   at AWSLambdaLCSTest.Function.GetAll(NpgsqlConnection connection, String schema, String table) in C:\Users\JMatson\source\repos\AWSLambdaLCSTest\AWSLambdaLCSTest\Function.cs:line 109

   at AWSLambdaLCSTest.Function.FunctionHandler(String input, ILambdaContext context) in C:\Users\JMatson\source\repos\AWSLambdaLCSTest\AWSLambdaLCSTest\Function.cs:line 53

  Exception data:

    Severity: ERROR

    SqlState: 42601

    MessageText: syntax error at end of input

    Position: 22

    File: scan.l

    Line: 1126

    Routine: scanner_yyerror

EDIT: Updated by trying the below setting as per advice:

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

However debug output still doesn't show anything:

enter image description here

asked on Stack Overflow May 19, 2020 by JamesMatson • edited May 20, 2020 by JamesMatson

1 Answer


I wrote a blog post on this very recently. Are you using .net core?

Enable sensitive data logging in your startup.cs class and in the ConfigureServices method.

            cfg =>

Next configure the logging level to include ef in your config file. Usually appsettings.json

"Logging": {
    "LogLevel": {
        "Default": "Information",
        "Microsoft": "Warning",
        "Microsoft.EntityFrameworkCore.Database.Command": "Information"

Now run the application and you can view the sql in your output window if you select the web server as source of the output.

output window example

answered on Stack Overflow May 19, 2020 by Eamon

User contributions licensed under CC BY-SA 3.0