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  1. #1
    Join Date
    Dec 2016

    events based on a database(s) result


    I am a beginner attempting to transform to an intermediate C++ coder. I am looking for some ideas with regard to a homework task.

    The requirement is :
    - 3 different vendor databases (Oracle 11g, SQL Anywhere 17 and PostgreSQL 9.6), all have the same schema and data.
    - I am using SQLAPI++ to execute selects, updates, inserts & deletes (DML only!).
    - The responses from each DB are stored in a hash table (unordered_map), the key is the hash of the client and SQL statement and the value is a tuple of size three, which holds a struc
    - In the case of SELECT's a hash value(md5), instead of the full result set.
    - A class, Comparator, then compares the result.
    - The Comparator should start comparing when at least 2 results have been returned
    - if the 3rd result is present in the unordered_map, then if the comparison from the previous step is successful, the comparison to the 3rd result should proceed
    - the client is informed is result is positive or negative

    Summary of events:
    1. 2 results are present in the tuple (within the unordered_map)
    2. a third result has arrived
    3. the result comparison is positive
    4. the client is informed

    I have implemented a Boost.asio TCP/IP server to communicate to clients, but I would like to implement something different for the above summary of events,
    which forms a separate layer in the middleware.

    These are some of the options that I have read about thus far:
    - Boost.signals2
    - thread safe Observer Pattern
    - CAF_C++ Actor Framework

    I am unsure which is more appropriate and (for a beginner) the simplest to implement.
    Any suggestions on which I should focus on?

  2. #2
    Arjay's Avatar
    Arjay is online now Moderator / MS MVP Power Poster
    Join Date
    Aug 2004

    Re: events based on a database(s) result

    I don't know either, but I would recommended trying the sample code from each of the 3. That should help you decide which approach is best for you.

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