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John Hotalen · Apr 27, 2020

Question:   Is there certain permissions that your Cache User Account must have to use the %Library/Global query that you show in your ObjectScript example above?   I tried this example and got an error message that my account was not privileged for the operation.  I used your first ObjectScript example and just substituted my namespace, global name, and value I was searching for.

Thanks.

John Hotalen · Jan 25, 2018

(sitting here amazed that someone was kind enough to build in VMS support for the open source product - I have found that is VERY rare)

Thank you very much Dmitry for this additional information.  I will discuss options with our internal infrastructure teams to see what the process is for installing the VMS libraries for ImageMagick.  It would be really cool to have those types of image handling libraries for VMS.

Thanks again - You Rock!

John Hotalen · Jan 25, 2018

Hi Jorge,  Thank you for the response/suggestion.  While the ZEN Report would be an option, our lab application interfaces with a reporting system that generates the report.  Our lab application provides all the report data (including images) to the reporting system.  Since the report has limited real estate for where/how the images are displayed, I was looking for a way to resize the raw images from our lab application image repository when sending the report data and images to the reporting system.   Thanks again for the feedback. 

John Hotalen · Jan 25, 2018

Hi Dmitry,  Thank you for the quick response/suggestion.  I checked out the imagemagick web site and it appears that the software is primarily used on Windows and has some Linux distributions.  The challenge for me is that my company is using Cache with the VMS 8.4 operating system, so when the user (running Win7/Win10 PC) saves the image files to the image directory, the file is actually being saved to an underlying VMS operating system directory.  And our web application is running on Cache which is installed on VMS (the users interact with the web application via a web browser).   So I am not sure if that software would work.  Do you know if there are any image resize capabilities built into Cache?

John Hotalen · Sep 26, 2017

When it comes to creating development/coding standards for your company, there are a few key things to keep in mind.  First the standards document should account for both development standards, as well as, coding standards.

Here are some thoughts/suggestions to consider:   Disclaimer:  The content listed below is just ideas and not necessarily a proposal of what your development/coding standards should be.

  1. The document should consider code that will be added/modified to existing legacy code versus new code that is being added to the application.  My recommendation for the legacy code is to insure any new code added to the legacy code try to maintain the coding style of the legacy code so the code does not become hard to read.  Example:  If the legacy code uses the old Mumps style of coding with line tags, goto, short variable names (i.e. X, Y, Z, I, J, K, PN, etc...), then I do not recommend adding Cache ObjectScript (COS) procedure blocks within the legacy code, because if added within code that contains things like structured DOs, then it could have impact on process flow, variable scoping, etc...;  If you do decide that new code (i.e. new methods) added to legacy code should follow COS standards, then consider having a coding standards rule telling programmers to add new COS style code at the end of the legacy routine - to keep all the COS style coding at the end of the routine, so the core legacy code looks consistent - it helps with reading the code for support and maintenance.   And it would be ok to allow the legacy code to call to classes/methods or to use new intrinsic functions ($Case, $Replace, etc...)
  2. The document should outline the recommended Development Standards vs. Coding Standards
    • Development Standards would be things like how to implement the various frameworks for things like error handling, database maintenance auditing, web services, handing of I/O, each definition page must have a corresponding inquiry, rules around creating custom components/composites/data types, etc...
    • Coding Standards would be things like:
      • naming conventions for packages, classes, routines, properties
      • type of comments to use
      • allow use of blank lines for readability
      • Commands should be in mixed case (or all uppercase or all lowercase - whatever is preferred for your company)
      • all Commands should be expanded (or collapsed)
      • maybe a rule about line length
      • rules around use of streams
      • rules around use of triggers
      • rules around SQL queries (dynamic? class? embedded?)
      • date/time formats
      • control structures
        • IF - comma versus double ampersand or exclamation point versus double vertical bar
        • Do-While
        • For
        • While
      • transaction processing (be careful not to mix old Mumps based TP with Cache Objects TP)
      • Should Xecute be allowed?  Can be hard to debug/support
      • Post Conditionals
      • locking (this can have information in both the development standards and the coding standards)
      • and on...
      • and on....
  3. Depending on the type of applications that your company has, there may need to be standards for the old type of UI (green screen/roll-n-scroll) versus UI for web-based applications.   There would be a whole separate list of recommendations around web-based development standards versus older Mumps based applications.
  4. When considering things such as Error Handling - there should be standards for how to deal with error handling for web-based applications, web services, and old Mumps based applications.  As you know, error handling for web-based applications can be more challenging because of the number of layers that could be involved (client, middleware (could be many layers), server (could also be many layers))
  5. Standards around database design
  6. Standards around MVC
  7. code should be modular and methods should perform a specific task.  Do not try and create methods that do everything (UI layout, validation, database updates, etc...) in a single method.
  8. There may need to be a separate standards sub-section on use of procedure blocks, since there are many things to consider when using procedure blocks
  9. and on....
  10. and on....

Any development/coding standards document could be fairly lengthy.  But as everyone can agree, standards are very important to insure applications are implemented in a consistent manner, where the code is supportable, maintainable, and reusable.  But it is also important to allow some flexibility with the standards to allow programmers the opportunity to be innovative with how they develop code.  The challenge is finding the perfect balance.

Hope this helps and Have a Great Day!!!  Go Team!!

Happy Coding!!

John Hotalen · Sep 26, 2017

There are multiple options you can choose from when implementing automated actions as part of your application.  In the end, it all comes down to what solution fits best for your business use case.  Here are a few examples:

  • (automated option) You could implement a database trigger that would fire when a record is inserted or updated to your database table, where the trigger could perform some action, such as call a method to evaluate the record data and to auto-send a notification based on some business rule (i.e.  the debut date is greater than some date then auto-send the notification).  You will want to give thought to the business logic fired with the trigger to minimize performance impacts to your database transactions - but there are options for how to achieve that.
  • (automated option) You could setup a scheduled task to run at certain times of the day that would query your database table(s) for specific things and if those things (business rules) are true, then auto-send the notification
  • (manual option)  If you want a user to be the one who determines whether a notification should be sent out, then you could have a web portal application that would query your database table(s) and display key data values to the user.  Based on the data displayed, the user could manually select one or more rows and click a button or perform some action to cause the notifications to be sent.
  • and on....
  • and on....

Bottom line, it comes down to what option works best for your company/applications.

P.S.  Also, based on the size of your database tables, be sure to review the SQL Query Plans for each of your SQL Queries to insure your queries are performing optimally.  If necessary, add the appropriate indexes to the tables to help improve the query plans (and the query performance).

Hope this helps and Have a Great Day!!!   Go Team!!

John Hotalen · Jan 30, 2017

Also, I recommend using caution for when the cached queries are purged "dynamically".   Purging cached queries dynamically can add risk to users running the application, such as incorrect/incomplete data and/or application errors.   It is not a good practice to purge cached queries while users are actively using the application.  If the cached query routines are deleted while a user is in the middle of having resultset data retrieved that could cause unwanted behavior.   From what I understand of Cache Database Management, things like purging of cached queries should be done during slow/down times when users are not active on the system.    Please feel free to confirm this with the InterSystems team.

Best of luck and Happy Coding....

John Hotalen · Dec 19, 2016

Hi Sebastian,

If you add an  onloadHandler() method (which gets called when the page is first loaded), this method could call to the GetMessages class method to load your page property named Messages with the message content you want displayed on the page.  Then, a little later in the ZEN page creation processing when the server processing renders the ZEN page components, the <html> component will call to the DrawMessages method to load the message data on the page.

Hope this helps and Have a Great Day!!!

John

John Hotalen · Nov 14, 2016

Hi Marc,

As a starting point, I recommend that you have the developers review the Cache ObjectScript (COS) documentation at the InterSystems web site:  http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls

The documentation has many reference guides and tutorials that will be helpful for any developer (new or experienced).

The developers will quickly see a lot of similar comparisons between the basic Java commands and COS commands.  Cache has various looping structures, such as For, While, and Do..While looping commands.  COS procedure blocks has local variable scoping.  COS works hand-in-hand with Cache Objects and can call class methods, instance methods, etc...

The great news is that COS is very easy to learn and use for any developer.  Also, in addition to the online Cache documentation, there is the InterSystems Cache Developer Community that has tons of wonderful information.  After your developers start using COS/Cache Objects, have them join this community, so they can ask questions about specific design or coding issues they might encounter.  There is a whole international community of Cache Developers always willing to help out.

Best of luck to you and your developers.

Best Regards,

John Hotalen

John Hotalen · Oct 14, 2016

So to make sure I understand, what would the global structure look like if the [NoExtent] keyword is added?

I am guessing since the Person class is abstract - that the data would be stored in 

^USA.President - contains records for presidents

^USA.Senator - contains records for senators

^USA.Representative - contains records for representatives

But what happens if someone forgets to add [NoExtent] to the USA.Person class?

Then would the data be stored as

^USA.Person(seq,"President")

^USA.Person(seq,"Senator")

^USA.Person(seq,"Representative")

And if the [NoExtent] keyword is omitted, then would bitmap indexes need to be added for president, senator, and representative, since I am guessing the data would be stored within ^USA.Person?    Another question:  If the number of people in one of these sub-grouping would exceed 10,000, then would a bitmap index still be used?  Or should another type of index be used?

John Hotalen · Oct 7, 2016

Also, you could use a simple javascript method to retrieve the value for a specified request parameter from a URL.  Hope this helps and Happy Coding!!!

Example:

ClientMethod getRequestParameter(sParameterName) [ Language = javascript ]
{
    var sRegexPattern='[\\?&]'+sParameterName+'=([^&#]*)';
    var oRegex=new RegExp(sRegexPattern);
    var aParms = oRegex.exec(window.location.href);
    if (aParms == null) {
        return "";
    } else {
        return aParms[1];
    }
}
John Hotalen · Oct 7, 2016

You can use the example method (parseURLquery) that Sergei posted to get at the query (request params) information.  You might also consider applying the $zconvert code that Tomas recommended as a good practice to account for any possible encoding and or use of different character sets.   Also, Fabian was kind enough to post a link to InterSystems documentation that discusses the built-in (%Net.URLParser) Parse method - which would be useful/helpful, as well.