anchor.diff:      let c = withMemDb()
       let tran() = tx {
           for i in 1..50 do
  -            do! Tx.execNonQueryi "insert into person (id,name) values (@id, @name)" [P("@id",1);P("@name", "juan")]
  +            do! txInsert 1
       }
       let result = tran() c
       match result with
  
positive.code: let ``tx monad using`` () = 
      let c = withMemDb()
      let tran() = tx {
          do! Tx.execNonQueryi "insert into person (id,name) values (@id, @name)" [P("@id",3);P("@name", "juan")]
          use! reader = Tx.execReader "select * from person" []
          let id = 
              reader 
  
negative.code:         printfn "Error: %A" e
      | _ -> Assert.Fail("Transaction should have failed")
  
  let txInsert id = 
      Tx.execNonQueryi "insert into person (id,name) values (@id, @name)" [P("@id",id);P("@name", "juan")]
  
  [<Test;Parallelizable>]
  let ``tx monad error rollback`` () = 
      let c = withMemDb()
  