[OPEN-ILS-DEV] Removing URLS from 856
Liam Whalen
whalen.ld at gmail.com
Wed Apr 3 17:48:50 EDT 2013
I would still use SELECTs to see what you are replacing. Subfield u is repeatable, so if you have a 856 field with two URLs, one with your HCC link, and the other with a a different link but an HCC short name, that regex will replace that as well.
That is most likely an unusual situation, but if you are not really familiar with this data there is no way to know. I guess there is only so much that can be done with bad data, but I always feel better knowing that I'm not getting rid of something I am not anticipating deleting.
Liam
On 2013-04-03, at 9:13 AM, Tim Spindler <tjspindler at gmail.com> wrote:
> Thanks fro all the replies. I did get the following regex to work
>
> regexp_replace(marc,E'<datafield tag="856" ind1="4" ind2="0"><subfield code="u">http://ezhc.ez.cwmars.org:4000/login.url=http://digital.films.com/PortalPlaylists.aspx.aid=9206.+?HCC</subfield></datafield>','','g')
>
> The url is unique to Films on Demand for HCC so that seems to work well to identify the beginning part of the 856 and then the HCC part identifies the end.
>
>
>
>
> On Wed, Apr 3, 2013 at 6:51 AM, Liam Whalen <whalen.ld at gmail.com> wrote:
>> Sorry for the chain replying to my own emails. But, that code is not exactly right. using matches between ^ $ will not get you what you want exactly, that will only return the first occurrence of 856 replaced in a record. It has been over a year since I've done stuff like this, so I'm sorry if the code is not very usable. However, the code wasn't really my main point. What I've learned using regex to replace data is I expect regex to get rid of useful data because there is no way to predict the outliers in the data. Almost definitely, there will be some 856s fields that do not conform to typical pattern in your data, and regex may remove them, in which case you will lose useful data.
>>
>> Liam
>> On 2013-04-03, at 6:35 AM, Liam Whalen <whalen.ld at gmail.com> wrote:
>>
>>> I forgot to mention checking the data that was replaced:
>>>
>>> SELECT id, replaced FROM
>>> (SELECT id, regexp_replace(marc,E'^(?:(?!<datafield[^>]+?tag="856").)*(<datafield[^>]+?tag="856".+?<subfield code="9">HCC</subfield>(?:(?!</datafield>).)*</datafield>').*$,'\1','g') AS replaced FROM biblio.record_entry WHERE marc ~ '<datafield[^>]+tag="856"(?:(?!</datafield>).)*</datafield>')
>>> WHERE length(replaced) > 0
>>>
>>> That should give you all the fields that were replaced and the ids for their records. You can then use further selects to make sure you are only replacing what you think you are replacing. For instance, you can look for data that was coded improperly. Perhaps there is a link with an HCC in 9 that isn't really an HCC link.
>>>
>>> I'm not sure what determines if it is HCC, maybe its the port or the aid=#?
>>>
>>> Something like
>>>
>>> SELECT id, regexp_replace(replaced, E'^(?:(?!<subfield code="u">).)*([^<]*)</subfield>','\1','g') AS url FROM
>>> (SELECT id, replaced FROM
>>> (SELECT id, regexp_replace(marc,E'^(?:(?!<datafield[^>]+?tag="856").)*(<datafield[^>]+?tag="856".+?<subfield code="9">HCC</subfield>(?:(?!</datafield>).)*</datafield>').*$,'\1','g') AS replaced FROM biblio.record_entry WHERE marc ~ '<datafield[^>]+tag="856"(?:(?!</datafield>).)*</datafield>')
>>> WHERE length(replaced) > 0))
>>>
>>> WHERE url !~ '.*aid=9206.*'
>>>
>>> That should give you urls you are replacing that do not have aid=9206. I'm not sure what data you need to check for, but the idea is to not replace data that has been entered incorrectly. While it might have HCC in subfield 9, that could be there incorrectly, in which case you will be eliminating a useful URL that has been coded incorrectly. There are other things to check for. I'm not sure if there are limitations on the data's use of subfield 9. However it might be repeated in a url indicating that a link belongs to more than one shortname. In which case the second subfield would get eaten by the negative lookahead, and the 856 tag would be removed when it may still be valid for another shortname.
>>>
>>> Liam
>>>
>>>
>>> On 2013-04-02, at 11:32 PM, Liam Whalen <whalen.ld at gmail.com> wrote:
>>>
>>>> For the first SELECT you can use something like SELECT regexp_replace(marc,E'<datafield[^>]+?tag="856".+?<subfield code="9">HCC</subfield>(?:(?!</datafield>).)*</datafield>','','g') FROM biblio.record_entry WHERE marc ~ '<datafield[^>]+tag="856"(?:(?!</datafield>).)*</datafield>'
>>>>
>>>> That should give you your datafields without HCC. If you can search through the results for HCC and find any examples of HCC left, then you can improve the regex to catch them. Or opt for another non-regex route. If there are no HCC's left, then check to make sure you aren't missing some due to something else in the WHERE regex.
>>>>
>>>> SELECT no_hcc FROM
>>>> (SELECT regexp_replace(marc,E'<datafield[^>]+?tag="856".+?<subfield code="9">HCC</subfield>(?:(?!</datafield>).)*</datafield>','','g') AS no_hcc FROM biblio.record_entry WHERE marc ~ '<datafield[^>]+tag="856"(?:(?!</datafield>).)*</datafield>' )
>>>> WHERE no_hcc ~* <subfield code="9">HCC</subfield>'
>>>>
>>>> Its been a while since I've written that type SQL, and I don't have an Evergreen database to test it on. So, that may not work exactly as written, but that is the general idea on how to double check mass db updates. The idea with the last WHERE clause is to look for the least amount of data that could catch the HCC subfield. If you are willing to sort through some false positives, it might be worthwhile changing the where to '>HCC<' or even 'HCC', just to make sure you are getting everything. The idea being to look for malformed MARCXML. As well, I put a case insensitive regex search (~*) in the last WHERE clause. If you are sure all the HCCs are upper case you will not need that.
>>>>
>>>> Liam
>>>>
>>>>
>>>> On 2013-04-02, at 10:20 PM, Liam Whalen <whalen.ld at gmail.com> wrote:
>>>>
>>>>> You could also use negative lookahead to capture the 856 fields where subfield 9 is not at the end.
>>>>>
>>>>> regexp_replace(marc,E'<datafield[^>]+?tag="856".+?<subfield code="9">HCC</subfield>(?:(?!</datafield>).)*</datafield>','','g')
>>>>>
>>>>> I did not test this much either, but it does pick up only your HCC fields in the data you provided below. That being said, I was always surprised when using regex on large sets of data. A good way to test this is to run it as a SELECT first to try and pull records with that regex, then grep through them to make sure you are only getting rid of the data you want. Then for completeness, do another select for 856 fields with a WHERE clause using your regex to exclude the items you just verified for completeness, and grep through those results to make sure you are not missing any 9 = HCC fields.
>>>>>
>>>>> Liam
>>>>>
>>>>>
>>>>> On 2013-04-02, at 10:14 AM, Mike Rylander <mrylander at gmail.com> wrote:
>>>>>
>>>>>> On Tue, Apr 2, 2013 at 9:43 AM, Tim Spindler <tjspindler at gmail.com> wrote:
>>>>>>> This is the regex I was trying but in testing it wasn't working.
>>>>>>>
>>>>>>> regexp_replace(marc,E'<datafield[^>]*?tag="856"+?<subfield code="9">HCC</subfield></datafield>','','g')
>>>>>>
>>>>>> Perhaps something like: regexp_replace(marc,E'<datafield[^>]+?tag="856".+?<subfield code="9">HCC</subfield></datafield>','','g')
>>>>>>
>>>>>> As long as subfield 9 is at the end of all the datafields, that should work. It's not heavily tested.
>>>>>>
>>>>>> --miker
>>>>>>
>>>>>>>
>>>>>>> On Tue, Apr 2, 2013 at 9:41 AM, Tim Spindler <tjspindler at gmail.com> wrote:
>>>>>>>> Mike,
>>>>>>>>
>>>>>>>> For the batch update, it is about 6000 records with bucket, I didn't think Evergreen could handle that many in a bucket.
>>>>>>>>
>>>>>>>> Tim
>>>>>>>>
>>>>>>>>
>>>>>>>> On Tue, Apr 2, 2013 at 9:20 AM, Mike Rylander <mrylander at gmail.com> wrote:
>>>>>>>>> If your removal code is regexp-based, you'll just need to match on HCC in the middle of the "find for removal" regexp. Alternatively, you could apply the batch MARC update function to a bucket or CSV file full of the records. That has the ability to modify records conditionally, based on subfield content within a datafield.
>>>>>>>>>
>>>>>>>>> --miker
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Tue, Apr 2, 2013 at 9:12 AM, Tim Spindler <tjspindler at gmail.com> wrote:
>>>>>>>>>> We have a library that wants to reload its Films on Demand records. These records have multiple 856s for other institutions with the subfield 9 associated with their shortname. What would the best way be to remove these for instance. I have created a list of the records needing updating in the staging table. Here is an example of the of he 856. I have code that can remove all the 856s but am having trouble removing just one. We just want to remove the one for HCC (although I'll take suggests for removing the duplicate QCC lines also)
>>>>>>>>>>
>>>>>>>>>> <datafield tag="856" ind1="4" ind2="0"><subfield code="y">Click here to access this film online (MCLA students, faculty, and staff only)</subfield><subfield code="u">http://libproxy.mcla.edu:2048/login?url=http://digital.films.com/PortalPlaylists.aspx?aid=11580&xtid=152</subfield><subfield code="9">MCLA</subfield></datafield>
>>>>>>>>>> <datafield tag="856" ind1="4" ind2="0"><subfield code="u">http://ezhc.ez.cwmars.org:4000/login?url=http://digital.films.com/PortalPlaylists.aspx?aid=9206&xtid=152</subfield><subfield code="y">Click here to access this film online (HCC Students and Staff only)</subfield><subfield code="9">HCC</subfield></datafield>
>>>>>>>>>> <datafield tag="856" ind1="4" ind2="0"><subfield code="y">Click here to access this film online (QCC studetns, faculty, & staff only)</subfield><subfield code="u">http://ezqc.ez.cwmars.org:5200/login?url=http://digital.films.com/PortalPlaylists.aspx?aid=19277&xtid=152</subfield><subfield code="9">QCC</subfield></datafield>
>>>>>>>>>> <datafield tag="856" ind1="4" ind2="0"><subfield code="u">http://ezhc.ez.cwmars.org:4000/login?url=http://digital.films.com/PortalPlaylists.aspx?aid=9206&xtid=152</subfield><subfield code="y">Click here to access this film online (HCC Students and Staff only)</subfield><subfield code="9">HCC</subfield></datafield>
>>>>>>>>>> <datafield tag="856" ind1="4" ind2="0"><subfield code="y">Click here to access this film online (QCC studetns, faculty, & staff only)</subfield><subfield code="u">http://ezqc.ez.cwmars.org:5200/login?url=http://digital.films.com/PortalPlaylists.aspx?aid=19277&xtid=152</subfield><subfield code="9">QCC</subfield></datafield>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> Tim Spindler
>>>>>>>>>> tjspindler at gmail.com
>>>>>>>>>>
>>>>>>>>>> P Go Green - Save a tree! Please don't print this e-mail unless it's really necessary.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Mike Rylander
>>>>>>>>> | Director of Research and Development
>>>>>>>>> | Equinox Software, Inc. / Your Library's Guide to Open Source
>>>>>>>>> | phone: 1-877-OPEN-ILS (673-6457)
>>>>>>>>> | email: miker at esilibrary.com
>>>>>>>>> | web: http://www.esilibrary.com
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Tim Spindler
>>>>>>>> tjspindler at gmail.com
>>>>>>>>
>>>>>>>> P Go Green - Save a tree! Please don't print this e-mail unless it's really necessary.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Tim Spindler
>>>>>>> tjspindler at gmail.com
>>>>>>>
>>>>>>> P Go Green - Save a tree! Please don't print this e-mail unless it's really necessary.
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Mike Rylander
>>>>>> | Director of Research and Development
>>>>>> | Equinox Software, Inc. / Your Library's Guide to Open Source
>>>>>> | phone: 1-877-OPEN-ILS (673-6457)
>>>>>> | email: miker at esilibrary.com
>>>>>> | web: http://www.esilibrary.com
>
>
>
> --
> Tim Spindler
> tjspindler at gmail.com
>
> P Go Green - Save a tree! Please don't print this e-mail unless it's really necessary.
>
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