Re: Server side prepared statements 'bit' parameters generate errors.

On 10/04/2016 07:35 AM, Johan Levin wrote:

Hello

I have run into a problem after upgrading from 9.03 to the 9.05.04 ODBC
driver. Parameters of type 'bit' seem to be interpreted as 'char' in
some cases when using server side prepared statements.

If I execute the query
    select * from some_table where ?;
with a bit parameter then I get an error that reads:
    ERROR [42804] ERROR: argument of WHERE must be type boolean, not
type "char";

The error is not reproducible is I set the connection string
parameter UseServerSidePrepare=0. It also isn't reproducible in version
9.03 regardless of the value of UseServerSidePrepare. The problem seems
to only affect bit parameters. A program that duplicates the problem
follows at the end of this email. I am using the driver distributed in
"psqlodbc_09_05_0400-x64.zip" on Windows 10. I have tested PostgreSQL
version 9.4 and 9.5.

Have I run into a bug in the driver, or is this a server issue? Any help
would be much appreciated.

Got to believe it is related to:

https://odbc.postgresql.org/docs/release.html
"
psqlODBC 09.05.0100 Release

....

12. Send datatype information for query parameters, when known
If a query parameter is bound with a specific SQL type, pass on that information to the server. This makes the behaviour of queries like "SELECT '555' > ?" more sensible, where the result depends on whether the query parameter is interpreted as an integer or a string.

....

"

Regards,
Johan Levin




Program listing: (C#)

using System.Data.Odbc;
using System.Diagnostics;
internal class Program
{
    private static void Main(string[] args)
    {
        // Command line: Server, User, Password, Database,
UseServerSidePrepare
        // Database schema and data:
        //   create table some_table (id int, name varchar(20));
        //   insert into some_table values (42, 'Arthur Dent');

        Trace.Assert(args.Length == 5, "Wrong number of command line
arguments.");
        var connStr = string.Format("Driver={{PostgreSQL
Unicode(x64)}};Server={0};Uid={1};Pwd={2};Database={3};UseServerSidePrepare={4}",
args);
        using (var connection = new OdbcConnection(connStr))
        using (var command = connection.CreateCommand())
        {
            connection.Open();
            command.CommandText = "select * from some_table where ?;";
            command.Parameters.Add(new OdbcParameter
            {
                OdbcType = OdbcType.Bit,
                Value = 1
            });
            command.ExecuteNonQuery();    // <-- Exception here if
UseServerSidePrepare=1
            // OdbcException.Message =
            //   ERROR [42804] ERROR: argument of WHERE must be type
boolean, not type "char";
            //   Error while executing the query
        }
    }
}

--
Adrian Klaver
adrian.klaver@aklaver.com