Database script doesn't edit database

Hi.

Trying to edit a database, but database doesn't change, when starting the script. Can somebody help to find an error?

Code:

1. string connectionString = "Data Source=file:Base123.db";

2.      IDbConnection dbcon;
   

3.      dbcon = (IDbConnection)new SqliteConnection(connectionString);
   

4.      dbcon.Open();
   
   

5.     sql = "INSERT INTO TheTable (UserName, Min) VALUES ('"
             + UserName + "'," + transform.localScale.x + ")";
   

6.     IDbCommand dbcmd = dbcon.CreateCommand();
   

7.     dbcmd.CommandText = sql;
   
        
   

8.      dbcmd.ExecuteNonQuery();
   
        
        
   

9.      dbcmd.Dispose();
   

10.      dbcmd = null;
    

11.      dbcon.Close();
    

12.      dbcon = null;
    
    

P. S. Getting this error on start:

MissingMethodException: Method not found: 'System.Threading.Monitor.Enter'. Mono.Data.Sqlite.SqliteStatementHandle.ReleaseHandle () System.Runtime.InteropServices.CriticalHandle.Dispose (Boolean disposing) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Runtime.InteropServices/CriticalHandle.cs:56) System.Runtime.InteropServices.CriticalHandle.Dispose () (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Runtime.InteropServices/CriticalHandle.cs:42) Mono.Data.Sqlite.SqliteStatement.Dispose () Mono.Data.Sqlite.SqliteCommand.ClearCommands () Mono.Data.Sqlite.SqliteCommand.set_CommandText (System.String value) Mono.Data.Sqlite.SqliteConnection.Open () DataControls.Start () (at Assets/Scripts/DataControls.cs:22)