Results 1 to 5 of 5

Thread: Using Meta data to update other fields based on entries in a field

  1. #1
    Senior Member
    Join Date
    Apr 2012
    Location
    United Kingdom
    Posts
    552

    Using Meta data to update other fields based on entries in a field

    I'm working on some code to sync my Liana databases with my Xcase model.

    Is the following possible in Lianja, using meta data so that I can simply update the meta data rather than having code in the UI.

    Three fields

    The mother of an animal cfk_danimal - foreign key to the animal table
    The father of an animal cfk_danimal0 - foreign key to the animal table
    The species of their offspring cfk_dtaxon - foreign key to the species table

    In my current vfp system I have in Xcase some code in the cfk_dtaxon column that if cfk_daniml or cfk_danimal0 changes the code goes off and using those values returns the cfk_dtaxon value for the offering.

    All the code I have, just truing to figure out how to fire this using meta data in Lianja.\

    Another scenario might be three logical columns used as checkboxes on a page

    A, B, C

    Only one can be checked. If A is checked and user checks B then A unchecks itself.

    I know this is easy to do in the pages themselves, but if I can do it via meta data then I never have to lay hunt the code when I want to alter anything as it woudl all come from my Xcase model and be put into meta data by my conversion program.

  2. #2
    Lianja MVP
    Join Date
    Feb 2012
    Location
    Berea, KY, USA
    Posts
    2,071
    HI David,

    when a control changes, you then need to query the metadata, which might looks like "f2ref:" followed by an array of other columns to do things with, or might reference a prg. The metadata doesn't do the work: it's the code traffic controller information.

    Hank

    PS: you could do this in field triggers as well -- but that means you have to know where the code is running (don't want it running twice).

    PPS: for those who think calculated and recalculate would do the trick: scenarios exist where field a changes field b but field b then changes field c Plus field b can be changed independently and has to change field c. A calculated field can't also be a modifiable (recalculate) field.
    Last edited by HankFay; 2021-03-11 at 04:18.

  3. #3
    Senior Member
    Join Date
    Apr 2012
    Location
    United Kingdom
    Posts
    552
    Thanks Hank,

    Yes that is what I meant, a call to my own prg do do the work, just need to know how to trigger that via metadata

  4. #4
    Lianja MVP
    Join Date
    Feb 2012
    Location
    Berea, KY, USA
    Posts
    2,071
    This is your magic page: the attribute names for Fields: https://www.lianja.com/doc/index.php/Field_Attributes

    The Change event is the one you want: https://www.lianja.com/doc/index.php/Custom_Delegates#Change

    If you find data controls where there is no such event delegate, you know where to submit an ER. <gd&r from Barry>.

    Hank

  5. #5
    Senior Member
    Join Date
    Apr 2012
    Location
    United Kingdom
    Posts
    552
    Thanks Hank, that looks very promising.

    David

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Journey into the Cloud
Join us