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How to allo two comp to write into database at a same time? RRS feed

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    Hi all,

    I have a program -> it is stored in personal cloud -> to this cloud are connected three, sometimes more computers -> this program, written in C# of course, use sometimes more computers so they fill out some fields and try to store data ... BUT when they do it  at the sometime ... it couse an error ... different computer = different data ... saved data from  on PC are sometimes  same as saved data from another PC (but it filled different data)  ... How to allow more  comp access to the  database at the  same time?

    I hope you understand my question ... what I need to solve ... thank  you for  answers
    Monday, September 3, 2018 6:22 AM

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    Hi TakeshiKitano,

    According to your description, you want to allow multiple users to access database at the same time. When you update the data, the database will automatically lock this record.

     In multi-user environment it’s possible that multiple users can update the same record at the same time causing confusion between users.

    you will need to look into things like row locking, transactions, and isolation modes.

    There are some articles about this, you can take a look:

    https://docs.microsoft.com/en-us/sql/2014-toc/sql-server-transaction-locking-and-row-versioning-guide?view=sql-server-2014

    https://www.codeproject.com/Articles/114262/6-ways-of-doing-locking-in-NET-Pessimistic-and-opt

    If you use EF or ado.net, you can show your code here.

    Best Regards,

    Cherry

    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

    Tuesday, September 4, 2018 2:38 AM
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    I am very sorry ... excuse me for my english but I will try to describe my problem again (but  maybe your answer is right)

    1) - As it is mentioned above, program  is stored in personal cloud in which are connected more computer (for example two)

    2) - Both computer open that program at the same time and fill out some fields.

    3) First  one want to update old client's data - second one wants to insert new client's  data

    4) Both, of course, use another clientID ... BUT both use same fields from form

    5) Both push at the same time  button bntSave()

    6) It happened that  First PC updated old client with data that filled Second PC

    Now I hope it is more clear ...

    Thank you very much for your understanding


    Tuesday, September 4, 2018 10:29 AM
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    Then this sounds like there is something rather seriously wrong with your program, because it should not be possible for two different records to end up with the same data this way.

    There is nothing inherently wrong with multiple PCs connecting to the same database and all updating and adding at the same time. This is what databases are for!

    Generally the only things you need to consider are what to do if two people try to update exactly the same record at the same time. This is where you need to look at the things that Cherry Bu already mentioned in the post above.

    If you have a situation where two PCs should be updating or adding two completely different records, but are somehow conflicting then, as I said, something is seriously wrong.

    But this is going to be almost impossible to determine what without more information!

    E.g. Perhaps a rough idea of the data schema, and any parts of relevant code you could supply.

    Tuesday, September 4, 2018 11:02 AM
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    OK, so sam problem -> two PC's -> not one update and one insert ....  but both insert or both update
    Tuesday, September 4, 2018 11:56 AM
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    Hi TakeshiKitano,

    Since this forum is discussing question about wpf, but your issue is related database, if you use sql server database, I suggest you can ask your question at Sql server forum or C# forum for professional help.

    https://social.msdn.microsoft.com/Forums/sqlserver/en-US/home?category=sqlserver

    https://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=csharpgeneral

    Best Regards,

    Cherry

    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

    Thursday, September 13, 2018 6:34 AM