Thursday, December 18, 2008

SqlDbx - Really Cool

I was asked to work in a project migrating from classic ASP to .Net and the database used was Sybase ASE. The only option for DB coding, was to use the pre-installed SQLAdvantage.

The first thing I did was to search for a better tool and after getting SqlDbx I knew, I've got the best.

Guys in my team were thrilled at this product. I have recommended this one to my company's IT Tools department and I am sure each one of us would get the professional edition real soon.

Wednesday, December 17, 2008

Building a simple Dirty State Page in .Net with AJAX

I was building a small internal application for my company as a pilot application that tests the Business Object framework we had just built. This web application could well serve as a useful too.

And now I wanted to try out a simple dirty state page – a page that tracks any changes made to it and notifies accordingly to the user. With AJAX extensions, I know it was possible, there are options to extend and create your own control - like a DirtyStateUpdatePanel or something. Anyways, I just wanted to try a basic version - so here is the simple version that I came up with. Consider this as a work done for a proof of concept.

We need something to notify that the page has become dirty – even a div tag should be suffice
<div id="DirtyStateNotifyDivCtl" class="dirtyPanel" runat="server">div>

We need to notify if any of the bound controls have changed – we should be fine with each control’s changed event. Additionally we need them all to perform one common function – notify a dirty state change. So we can have our own event declared

Public Event DirtyStateChangedEvent(ByVal getDirtyStateMethod As IDirtyPage.GetDirtyState) Implements IDirtyPage.DirtyStateChangedEvent

And its handler:

    Protected Sub ValueChanged(ByVal getDirtySateMethod As IDirtyPage.GetDirtyState) Handles Me.DirtyStateChangedEvent

        With Me.DirtyStateNotifyDivCtl

            If getDirtySateMethod.Invoke() Then

                .InnerText = "*Unsaved Changes"


                .InnerText = " "

            End If

        End With

    End Sub

And a cheeky way to expose the raise event from Master Page:

    Public Sub RaiseDirtyStateEvent(ByVal getDirtyStateMethod As IDirtyPage.GetDirtyState)

        RaiseEvent DirtyStateChangedEvent(getDirtyStateMethod)

    End Sub

We need to get all our controls wrapped into an UpdatePanel to “Ajaxify” things.

We can wire up the page controls to one common event handler (you can have as many event handlers). And pass in a delegate of a GetDirtyState method and let the Master page take care of the display of the Unsaved change text – or clear the unsaved change text.

    Protected Sub Page_DirtyStateChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles EndDateTxtCtl.TextChanged, StartDateTxtCtl.TextChanged

        Me.MasterPage.RaiseDirtyStateEvent(AddressOf Me.GetDirtyState)

    End Sub


    Public Function GetDirtyState() As Boolean

        ' TODOK: loop through your controls and find out if the page has become dirty by any chance

        If Me.EndDateTxtCtl.Text <> Me.TeamProject.EndDate Then

            Return True


            Return False

        End If


    End Function

And the icing on the cake would be the following:
<script language="javascript" type="text/javascript">

window.onbeforeunload = confirmIfDirty;

function confirmIfDirty(){

    if(document.getElementById('ctl00_DirtyStateUpdatePanelCtl').innerText > "")    {

        event.returnValue = "There are some unsaved changes. Navigating away from this page would cause such data to be lost.";




The slick onbeforeunload event pops up every time the user tries to navigate away from the page leaving it dirty.

You can find the sample files here.


Questions… Projects… - my two cents

A few years back, I happened to hear a glorified programmer advising his self-proclaimed sidekick how important it is to ask lesser questions to technical stakeholders/business users about the project or technology that they are working on.

I couldn’t disagree more! He was arguing that one should ask “smart” questions and should never let the other person think we do not know anything about the business by asking "stupid" questions.

Let me put this straight - There is nothing called as a stupid question. People get annoyed only when they get repeat questions. It would make them nervous on whether you are really on top of things.

For the benefit of the developer and for the benefit of the project, one should ask as many questions as possible. I am sure that clients who want the project done successfully would love to give you the answers. Even if they don’t have it with them immediately, it would kick start the thinking process and will make them revisit the requirements.

It helps to clarify a lot of things and verifies your assumptions. I strongly believe in this – “Assumption is the mother of all mess-ups”. It is wise to put forward your assumptions and sort it out. Nothing wrong in asking something basic about the business, after all you are going to be held responsible for the project you are build, aren’t you? The client would also be expecting you to know what you are doing.

Asking a lot of questions make you smart.
Asking only smart questions could leave even you in a lot of doubt.

Sybase stored procedure bug!?! Due to renamed table

We were investigating an issue with a web page – that displays data from a Sybase database. The problem was simple – the data was not as expected. The values were missing.

When we queried the actual table (say TableA) from which the stored procedure selects, the information was there. But on running the stored procedure, there would be no results.

We first suspected the parameters that were being passed in – but they were fine.

We then ran the stored procedure with IO statistics On and traced the culprit. The stored procedure was selecting records from a totally different table (TableA_old). The logical explanation is this:

Somebody renamed TableA to TableA_old. Thereby breaking all stored procedures, views depending on it. Later this somebody made another table by the same name TableA. But that does not fix the things that were broken earlier by the renaming.

The stored procedure (which is precompiled) was still pointing to the old table since it was referencing the table using id’s used internally by the database.

We saw if there was an option to recompile as I remembered that there was a sp_recompile, but that did not help. I played around with sp_recompile and it did mark the table to cause all associated sp’s to be recompiled the next time it was run. But when I ran the stored procedure again, it recompiled (there were 2 IO Stats entry), but both were pointing to the old (renamed) table only.

We then dropped and re-created the stored procedure and that fixed it all.

Tthe Sybase version I was working on was quite an old one:
“Adaptive Server Enterprise/12.5.3/EBF”

Here is a quick way to find out what version you are in. SELECT @@version
To just give some code examples to reproduce this error, try this on some old version of Sybase:

name VARCHAR(10)

SELECT name FROM tbl1

EXEC sp_tbl1

Table: tbl1 scan count 1, logical reads: (regular=1 apf=0 total=1),
physical reads: (regular=1 apf=0 total=1), apf IOs used=0

sp_rename 'tbl1','tbl1_old'

name VARCHAR(10)

EXEC sp_tbl1
Table: tbl1_old scan count 1, logical reads: (regular=1 apf=0 total=1),
physical reads: (regular=0 apf=0 total=0), apf IOs used=0

DROP TABLE tbl1_old

Sunday, December 14, 2008

How to extract contents from .msi files - Windows XP

My company’s strange “security” policy granted me administrator rights ONLY on my PC, but did not add me up to the administrators group of the domain to which my user account belonged to. That gave me kind of mixed permissions – and often caused some annoying “You do not have permissions” error. One such thing was - running an .msi file. I was installing AJAX Extensions when this one popped up again.

I have done some workarounds before for normal executables (.exe), with my handy WinRar, which would extract all contents of a setup package. But I was dealing with this Microsoft Installer, which was a bit tricky. But surfing through MSDN helps, as always! Learnt how to do it the black & white way:

Run the following on command prompt:
msiexec /a “the msi file with path” /qb TARGETDIR=”the path where you want the contents to be extracted”

msiexec /a “D:\Installers\AJAXExtensions.msi” /qb TARGETDIR=”C:\AjaxExtensionsExtracted”

Since I was an administrator on my local machine, I knew I had the rights to run the contents from the extracted folder. Well, at least I did not sweat much on it.

Release Process !?!

Two days back, my teammate had to release to production a minor code change he made to one of the web modules. Since we both were new to the release process followed by the client, we were given a small briefing about it.

We first have to release the change to a common dev environment, where it will reside till the peer review and internal testing is completed. Then we had 3 documents to be meticulously filled up for the UAT (User Acceptance Testing). One of the documents gives a clear step by step instruction on how to release to the QA environment, explaining like it is being told to a 4 year old. Once the UAT release is done, the development team we would get an email notification and after the user test it, there would be yet another email notification giving a sign-off for a production release.

We then have to prepare another bunch of documents, add with that the UAT sign-off email and the UAT release notification email and send it across to the deployment and maintenance team at the client side, who would take care of the release. They follow a semi-automated release process whereby the release manager would just specify the steps to be executed and the scheduled deployment runs once every 3 hours.

On the release date, if you never hear back from the release manager, things are good. But if you get an email with a high alert… you probably woke up on the wrong side of the bed that day.
Well, apparently that’s what my teammate would have possibly done, because he had just received such an email. He had a senior colleague to help him figure out the problem. So I decided to keep away from it, after just telling to compare the code changes in source control and holler if he needs any assistance. I decided to stay out of it partly because I did not want to jeopardize the senior colleague’s approach and also because I myself had a couple of burning issues, to attend to.

While I was keeping busy, later that evening I heard from this teammate that they had to rollback the changes after trying a couple of things and that this has been escalated and needs to be re-released the next day. They had identified that a few things were not matching up with the QA and Production environment. But they had figured out what the problem was and they were prepared for the next day’s release. While he was explaining I asked a few questions for which he either had no answers or was not confident of them, which made me a bit nervous for him.
Well, it was the next day - same time, and sadly the same story. It was a Friday and people were all the more frustrated and this colleague of mine was being made responsible and he had no clue what was going on. When things were going towards yet another rollback, I decided to jump in, invited or not.

They had this published website which was released to UAT – which worked fine, but when released to production, it failed to even load the default page and redirected to an authentication failed error page. The “fix” after the first rollback was this – they had compared the config file and found some application specific Role-id’s to be different and assumed that this must have been the issue and prepared themselves to give another shot, which eventually failed – miserably.

The code version in the source control looked intact, leaving me no other option but to decompile. Reflector, my favorite tool in many instances came to the rescue and I decompiled the app code binary of the current version in production with ours. When I saw the decompiled login related method, it seemed to contain quite a lot of additional changes – changes that were not present in source control!

We then figured out a way to get this work by making a few changes in the configuration file. Call it a tweak or a hack but it saved the day and the weekend, but I made it aware to all the people involved in this including the client who got an emergency regression test run and also promptly created another request to get this mess cleaned up.

I have worked quite a bit in this onsite/offshore setup and have my own experiences to recon. But almost no client I have worked with before had such an elaborate documentation process. So at first I appreciated this way of working, but this incident clearly proved that no system or process is invincible to errors, not when people have the audacity to bypass certain rules.
This whole thing was obviously caused due to someone who had been here long enough and knew how to sidestep a few landmines, but unfortunately did not know or care about the consequences and complications it would create to the next bunch of people who would work on it. The blame game had started, and something tells me that whoever did this must have been long gone.

Even though I come from a background where documentation was not so much patronized, I still could suggest on maintaining a “deviation log” which can be mainly used to record any such deviations, in any step of the development life cycle.

The bottom line is this - 
Even though there are a lot of steps to streamline any work process – nothing could change unless people learn to respect it and follow it.

Tuesday, December 9, 2008

Adding Properties to an object dynamically in VB.Net

In the current application that I am building, I came across this scenario where I had to add properties to an object during runtime.

Basically it is like this:

I had to display some data of a parent object on a grid – but the number of columns to display depended on the number of child objects the parent had. I usually build a façade object as a standard practice to bind any such modified/tweaked/manipulated data objects.
In order to explain the problem clearer, let me give an example.

Say we have “Product”, “ProductVersion” and “Order”. There could be multiple versions for the product and the relationship is one-to-many. “Order” and “ProductVersion” have a foreign key constraint.

In the middle tier we have Product class and ProductVersion class that map directly to each table. The requirement is to display in grid on the Products page that shows the following –

·         A side by side comparison of each version’s cost breakdown

·         Display is based on the Order Status

Product’s Order Status

Version 1

Version 2

Version 3









Pending Payment




One way is to get this whole thing done in a stored procedure. But just to make it happen in the middle tier, I dived into the world of TypeDescriptionProvider, partly because on an earlier project, when we encountered a similar problem, we chickened out of it by forcing the user  to change the functionality ( only due to lack of time).

Anyways, here goes the solution. You can get the actual code in zipped format here.
I am just explaining the most important parts:

The Class that I am going to build to bind with the grid is called – “ProductVersionFaçade”
The properties it will have – OrderStatus, and the rest of the properties would be Dynamically added.
Mark the façade class to use the TypeDescriptionProvider which we are about to build

GetType(ProductVersionFacadeTypeDescriptionProvider))> _

Public Class ProductVersionFacade

Let us have a dictionary inside this to hold our dynamic properties. You will see its usage later.

We then create our TypeDescriptionProvider as follows:

    Public Class ProductVersionFacadeTypeDescriptionProvider

        Inherits TypeDescriptionProvider

And override the GetTypeDescriptor function, which will return a CustmTypeDescriptor, which is also something we are going to build:

    Public Class ProductVersionFacadeTypeDescriptor

        Inherits CustomTypeDescriptor

This is the class where the most important GetProperties function will be overridden and inside that we add our new bunch of properties like this:

With propCollection

    Dim attArr() As Attribute

    ReDim attArr(MyBase.GetAttributes.Count - 1)

    MyBase.GetAttributes.CopyTo(attArr, 0)


    If TypeOf (_instance) Is ProductVersionFacade Then

        f = DirectCast(_instance, ProductVersionFacade)

        For Each i As Integer In f.DetailHourDict.Keys

            keyString = String.Format("ProductVersion_id{0}Cost", i)

            .Add(DirectCast(New ProductVersionFacadePropertyDescriptor( _

                    keyString, GetType(Integer), attArr), PropertyDescriptor))


    End If


End With

This is where we add the properties to the instance’s dictionary. And if you note we are adding a custom PropertyTypeDescriptor, we need that too. So we build the ProductVersionFacadePropertyDescriptor which among many other things overrides the GetValue function to return the value for your newly added properties.

Back to the Façade class, we overload the default property of it as follows:

        Default Public Property Item(ByVal fieldName As String) As Object


                Dim value As Object = Nothing

                If _customPropsDict.ContainsKey(fieldName) Then

                    value = _customPropsDict(fieldName)

                End If


                Return value

            End Get

            Set(ByVal value As Object)

                _customPropsDict(fieldName) = value

            End Set

        End Property

And a sample from the Page where it is bound:

Private Sub BindFacades()


   Dim list As List(Of ProductVersionFacade)

   list = ProductVersionFacadeSvc.BuildFacades(Me.Product)


   Dim keyString As String = String.Empty

   Dim idString As String = String.Empty


   For Each f As ProductVersionFacade In list


       For Each i As Integer In f.ProductVersionCostDict.Keys

           keyString = String.Format("ProductVersion_id{0}Cost", i)

           idString = String.Format("ProductVersion_id{0}", i)


           If f._customPropsDict.ContainsKey(keyString) Then

              f._customPropsDict(keyString) += f.ProductVersionCostDict(i)


              f._customPropsDict(keyString) = f.ProductVersionCostDict(i)

           End If

           f._customPropsDict(idString) = i




   With Me.ProductVersionFacadesGridViewCtl

        .DataSource = list


   End With

End Sub

Thursday, December 4, 2008

Output Parameter from stored procedures in Sybase ASE

I have never worked with Sybase, until recently – since one of my current employer’s clients is having their data almost fully in Sybase. A really early version of Sybase too.

Now there are a slew of things that you would have to re-adjust to when you are working with Sybase, especially after working extensively and entirely in SQL. Sybase is case sensitive and we are currently given to work with SQL Advantage which is a pretty naïve tool and stands no where close to my favorite Query Analyzer. But of course, it was built for the yesteryears. If there is anyone I should blame, it must be the client for still not upgrading!

So, as and when I learn something, I would try to note it down here.

First thing I learnt –
Output parameters on Sybase stored procedures would not return back to your recordset.

Usual workarounds
Will “Select” the value and get it as part of the result set

Actual Fix
Set the CursorLocation property of the Connection object to adUseClient ( value 3), like this:

objConn.CursorLocation = adUseClient


objConn.CursorLocation = 3