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Critical - RETS search returning different columns in result set

asked 2019-09-10 16:07:24 -0600

My implementation of retrieving data from uses Python and the 'rets' library. The search takes parameters:

  1. resource=Property
  2. resource_class=RE_1
  3. limit=25 // really an arbitrary integer
  4. search_filter= text for state, county, and listing date range

This works fine... however, I've seen that results in one date range (e.g. 9/1/2019 - 9/10/2019) differ from another (e.g. 1/1/2000 - 9/10/2019). Differences seen include:

  • Addition of LM_Char25_10
  • Dropping of LM_char10_44
  • Dropping of LM_char10_46
  • Et cetera

Is the server supposed to return varying results like this? If so, is there a different method to get the full (non-variable) result set every time?

This implementation requires a consistent data set be output from the search every time.

Please advise, thank you.

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answered 2019-09-10 18:18:12 -0600

The MLS can sometimes add or remove fields and the change will register when the next RETS Refresh is done.
Wyoming had one done on 9/9/2019 which would probably be why you are seeing a difference in the fields.
I guess I don't understand the issue you are referring to with date ranges?
When it comes to modification dates though, they are in UTC.

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The add/remove done on 9/9 caused what I saw with the WY data. It's not clear to me how to best handle this scenario though. How often do these changes take place? Our implementation downloads data via RETS, stores it, and then presents it to the user so they can add custom data based on onsite appraisal work. Storing data sets that have the columns periodically changed is fraught with headache! There really should be a consistent API. Is there someone I can speak to? kmccartney@gmecwy dot com

Kevin McCartney gravatar imageKevin McCartney ( 2019-09-11 08:10:34 -0600 )edit

Fixed typo in my email address. Sorry.

Kevin McCartney gravatar imageKevin McCartney ( 2019-09-11 14:04:23 -0600 )edit

When you login to RETS it returns metadata version information that can be used to determine if changes have been made.
Another way is instead of using all the columns returned, select the ones you need and pass them in the search Select parameter so that it only returns those fields.

bwolven gravatar imagebwolven ( 2019-09-11 18:04:31 -0600 )edit

Hi Bwolven, the approaches suggested really aren't what I'm after. I'm using structured data, so I have a table created with all the expected columns. Retrieving the metadata, parsing it, and egregiously updating the table based on changes won't work for us. And when I search I'm getting back 156 parameters consistently having values - not a small set mapping to what I search with. I need a consistent way to get the same results. With whom may I speak about this?

Kevin McCartney gravatar imageKevin McCartney ( 2019-09-12 09:08:38 -0600 )edit

You would probably need to contact the MLS directly and ask them inform you when they are making field changes in the system. RETS basically follows whatever changes they make in the system.

bwolven gravatar imagebwolven ( 2019-09-13 10:11:18 -0600 )edit

Hi Bwolven, OK - I highly expect to do as you said for our implementation. Additionally, am I missing something -- why are Paragon field names different from other vendors field names? So the L_ListingID, L_* and other field names I use to parse this data set are Paragon-proprietary. Is there not a cross-vendor standard? Thanks very much.

Kevin McCartney gravatar imageKevin McCartney ( 2019-09-26 16:45:10 -0600 )edit
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Asked: 2019-09-10 16:07:24 -0600

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Last updated: Sep 10 '19