Results 1 to 13 of 13

Thread: Work Flow Query - Regarding VB6 to VB.Net Migration

  1. #1

    Thread Starter
    Lively Member
    Join Date
    Jan 2017
    Posts
    68

    Work Flow Query - Regarding VB6 to VB.Net Migration

    Ok so a quick background i have taken over development of a front end system (access database back end) which consists of approx. 75+ forms 500K+ lines of code. Over the last 6 months i have been gradually weeding out the bugs the previous developer (who had also inherited this program) never had time to do before he retired. I am just at a stage now where the front-end is stable and ready to move onto the next stage of development.

    I have two paths for the next major stage of development. This is either to start migrating the code for the front-end program over to the .Net environment (something our company wants to achieve by 2020 although this will likely take a year or two as i cannot work on this full-time if we don't hit to many bumps in the road) and then migrate our database from access to a sequel database. Or we do the database first followed by the code. Which way would you guys recommend? Most calls to the access database are using DAO so i assume if we move over to sequel this will need to be rewritten using ADO (is that correct? i have little experience with sequel databases).

    The access data base is a concern currently as it's 500mb+ and contains 1 million+ entries so it has somewhat out grown Access at this stage and is only going to continue to grow day by day.

  2. #2
    PowerPoster
    Join Date
    Jun 2015
    Posts
    2,224

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    I've always migrated the database first. Then you can run the new/old front ends in parallel.

    edit: the actual DAO code itself should be able to stay the same, but if you're using SQL syntax directly - those queries may need to be updated.
    Last edited by DEXWERX; Jun 20th, 2017 at 10:45 AM.

  3. #3
    PowerPoster ChrisE's Avatar
    Join Date
    Jun 2017
    Location
    Frankfurt
    Posts
    3,046

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    Depends really on a few things

    how long did it take to reach 500mb?

    I would first ask If all the Data is requierd in ONE Database.

    Data for comparing(like 'Products sold' etc..) the Years from 2005 to 2016. could
    be in a diffrent Access Database

    its hard to give an statement if you should use Access or SQL-Server ...

  4. #4
    Fanatic Member
    Join Date
    Jan 2013
    Posts
    759

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    Millions of row in an MS Access database that used by multiple people?
    [Long overdue] Time to move it to SqlServer.

    It's relatively straightforward to migrate the data into SqlServer and have Access replace its "local" tables with "Linked" ones that "point" to the real ones now in SqlServer. This arrangement also allows you to write your new, replacement application directly against SqlServer but still retaining the Access "front-end" until such time as it becomes redundant.

    Regards, Phill W.

  5. #5
    PowerPoster ChrisE's Avatar
    Join Date
    Jun 2017
    Location
    Frankfurt
    Posts
    3,046

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    @Phill
    the Database seems to programmed with DAO, so the Data(1mio records+) has gathered over the last perhaps 20 year's?

    just a thought

  6. #6
    Fanatic Member
    Join Date
    Jan 2013
    Posts
    759

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    > "the Database seems to programmed with DAO ..."

    Languages are just tools to do a job; they come and go (especially in the Microsoft World).

    Remember; the O.P. could leave all this running exactly as it is for many years and it might be fine. If it does what the user[s] need it to do then why change it? That will cost [them] money. If course, if the application doesn't move forward, it runs the risk of falling into the "Obsolescence Trap", like so many other, older Microsoft technologies, at which point it breaks completely and we're forced to rewrite it on a ridiculously short timescale. It's better to keep the "upgrades" trickling along more gradually.

    > "... the Data(1mio records+) has gathered over the last perhaps 20 year's?"
    Quite possibly but so what? In my experience, 1 million rows is going to stress Access; it's nothing to SqlServer.

    Regards,
    Phill W.

  7. #7
    Superbly Moderated NeedSomeAnswers's Avatar
    Join Date
    Jun 2002
    Location
    Manchester uk
    Posts
    2,660

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    its hard to give an statement if you should use Access or SQL-Server ...
    Really it's not hard at all. Considering the amount of data you have you should be migrating away from Access and SQL Server is a good choice to move to.

    Also yes you should definitely move your data to a new database first. This will be the easier much less time consuming job.

    You should be able to run you existing system against your migrated SQL Server database no problem.

    There are built in Tools which will do much of the heavy lifting of the data migration for you, then you will just need to test you app against your new SQL database and change any queries where you using non standard sql (if you are using any - there are some statements you can use in access which you cant use in sql server)

    Obviously make sure you take backups of your database before you start this in case you have problems along the way

    Just search for "migrating database from access to sql server" in google and the top few links are all about migration tools!


    As for migrating your application, you would probably be best served doing it in a modular approach. Identify sections of the app and re-write it in more manageable pieces.
    Please Mark your Thread "Resolved", if the query is solved & Rate those who have helped you



  8. #8
    PowerPoster ChrisE's Avatar
    Join Date
    Jun 2017
    Location
    Frankfurt
    Posts
    3,046

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    good point !
    like so many other, older Microsoft technologies, at which point it breaks completely and we're forced to rewrite it on a ridiculously short timescale. It's better to keep the "upgrades" trickling along more gradually.
    regards
    Chris

  9. #9
    PowerPoster ChrisE's Avatar
    Join Date
    Jun 2017
    Location
    Frankfurt
    Posts
    3,046

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    Really it's not hard at all. Considering the amount of data you have you should be migrating away from Access and SQL Server is a good choice to move to.
    I just thought it was strange that DAO was in use, so only the thread starter
    can tell us how old this App. is

    regards
    Chris

  10. #10

    Thread Starter
    Lively Member
    Join Date
    Jan 2017
    Posts
    68

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    Hi all thanks for the replies. As many of you have stated it's forward thinking to start migrating over to .net now rather than when falling into the "Obsolescence Trap" as i am aware the migration would be very time consuming.

    I see the general consensus is to migrate to the database to SQL first which was my line of thinking. Especially as the database is on a local server and has multiple users connected to it at anyone time (another reason i feel it's out grown Access). I think i will write my proposal base on migrating the the database first and then followed by the code. I really appreciate all you insightful knowledge.

  11. #11

    Thread Starter
    Lively Member
    Join Date
    Jan 2017
    Posts
    68

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    Quote Originally Posted by ChrisE View Post
    I just thought it was strange that DAO was in use, so only the thread starter
    can tell us how old this App. is

    regards
    Chris

    The app has been under construction since approx 2004 but the original developer was old school and had only used VB6 and guess he was stuck in his ways and preferred to code using ADO.

  12. #12
    Fanatic Member
    Join Date
    Jan 2013
    Posts
    759

    Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    Or, equally likely:

    Manager: "Can you just add this feature ... ?"

    Developer: "I can do that in a couple of days, but you did say that we should re-write the whole application into Technology Z, and that will takes months."

    Manager: "We don't have the time/money for that; just add the feature".


    Rinse and repeat over a period of years and you get to exactly where you are now.

    Regards, Phill W.

  13. #13

    Thread Starter
    Lively Member
    Join Date
    Jan 2017
    Posts
    68

    Post Re: Work Flow Query - Regarding VB6 to VB.Net Migration

    Quote Originally Posted by Phill.W View Post
    Or, equally likely:

    Manager: "Can you just add this feature ... ?"

    Developer: "I can do that in a couple of days, but you did say that we should re-write the whole application into Technology Z, and that will takes months."

    Manager: "We don't have the time/money for that; just add the feature".


    Rinse and repeat over a period of years and you get to exactly where you are now.

    Regards, Phill W.
    Probably also a very valid point.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  



Click Here to Expand Forum to Full Width