Description:
Using MyOdbc 3.51/.Net C# to populate a database, I'm trying to use a generic template command to insert rows.  This table has a number of columns that can be null.  When I try to create an OdbcParamter() to pass that value, the code compiles and runs but throws a NullReference exception when I try
cmd.ExecuteNonQuery();.

More disturbing is that immediately after throwing that exception, the program crashes with an access violation.  Since .Net is all pointerless and memory managed my concern is that the hole is in the MyOdbc driver.

How to repeat:
In C#:
OdbcConnection activeDb = new OdbcConnection ("DSN=MySqldb");
activeDb.Open();
OdbcCommand cmd = activeDb.CreateCommand();
			
// Create table for this test if not existent
cmd.CommandText = "create table if not exists temp3 (\n"+
		"query TEXT NOT NULL,\n" +
		"first VARCHAR (10)\n" + // can be null
		") CHARACTER SET UTF8;";
cmd.ExecuteNonQuery();

// Set up insert command
cmd.CommandText = "INSERT INTO temp3 VALUES (?, ?)";
cmd.Parameters.Clear();
cmd.Add (new OdbcParameter("query", "here's a value"));
// Attempt 1 - NullReference exception, then crash on execute
     cmd.Add (new OdbcParameter("first", null));
/* also tried 
--------- Null reference exception, then crash on execute
     OdbcParameter x = new OdbcParameter("first", null);
     x.IsNullable = true;
     cmd.Add (x);
--------- NullReference exception, then crash on execute
     OdbcParameter x = new OdbcParameter ();
     x.IsNullable = true;
     cmd.Add (x);
--------- Conversion error; doesn't know how to use DBNull on constructor
     OdbcParameter x = new OdbcParameter ("first", DBNull.Value);
     cmd.Add (x);
*/
cmd.ExecuteNonQuery(); 
// crash occurs after exception is thrown

Suggested fix:
changing code to use .Net connector; seems to allow this operatio

Hi,

Could you please give us a fully functional test-case that reproduces this behaviour ?  Adding a complete C# project that reproduces this behavour would be of great help.

Thanks!!

I could reproduce this bug. Test case is attached.

Test case

Attachment: 11052.zip (application/x-zip-compressed, text), 3.76 KiB.

Is there a reason you're not using Connector/Net?

Hi Mark...
I used MyOdbc first because I figured it had been around longer and would probably be more stable.  I've had some similar problems with both, as you've seen in the cases I've filed.  Is development on MyOdbc still going on, or should everyone be better off to convert to Connector/Net?

Thanks
_mark

Could you please try with latest released version 3.51.19. Thanks in advance.

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

I'm closing this bug because I can not continue without feedback from the reporter. If you have new info, please reopen the report.