Avoiding duplicate clients

Lino Welfare offers some functionality for avoiding duplicate Client records.

This page contains code snippets (lines starting with >>>), which are being tested during our development workflow. The following snippet initializes the demo project used throughout this page.

>>> import lino
>>> lino.startup('lino_welfare.projects.gerd.settings.doctests')
>>> from lino.api.doctest import *

In Lino Welfare, a Client inherits from DupableClient.

Phonetic words

See lino.mixins.dupable.PhoneticWordBase.

>>> rt.show(pcsw.CoachedClients, column_names="id name dupable_words")
...
==== ======================= =========================================
 ID   Name                    dupable_words
---- ----------------------- -----------------------------------------
 17   Ausdemwald Alfons       `ASTMLT <…>`__, `ALFNS <…>`__
 78   Brecht Bernd            `PRKT <…>`__, `PRNT <…>`__
 19   Collard Charlotte       `KLRT <…>`__, `XRLT <…>`__
 25   Dobbelstein Dorothée    `TPLSTN <…>`__, `TR0 <…>`__
 80   Dubois Robin            `TP <…>`__, `RPN <…>`__
 29   Emonts Daniel           `AMNTS <…>`__, `TNL <…>`__
 53   Emonts-Gast Erna        `AMNTS <…>`__, `KST <…>`__, `ARN <…>`__
 30   Engels Edgar            `ANJLS <…>`__, `ATKR <…>`__
 28   Evers Eberhart          `AFRS <…>`__, `APRRT <…>`__
 33   Groteclaes Gregory      `KRTKLS <…>`__, `KRKR <…>`__
 34   Hilgers Hildegard       `HLKRS <…>`__, `HLTKRT <…>`__
 38   Jacobs Jacqueline       `JKPS <…>`__, `JKLN <…>`__
 82   Jeanémart Jérôme        `JNMRT <…>`__, `JRM <…>`__
 40   Jonas Josef             `JNS <…>`__, `JSF <…>`__
 42   Kaivers Karl            `KFRS <…>`__, `KRL <…>`__
 79   Keller Karl             `KLR <…>`__, `KRL <…>`__
 43   Lambertz Guido          `LMPRTS <…>`__, `KT <…>`__
 45   Lazarus Line            `LSRS <…>`__, `LN <…>`__
 47   Malmendier Marc         `MLMNT <…>`__, `MRK <…>`__
 48   Meessen Melissa         `MSN <…>`__, `MLS <…>`__
 54   Radermacher Alfons      `RTRMKR <…>`__, `ALFNS <…>`__
 56   Radermacher Christian   `RTRMKR <…>`__, `KRSXN <…>`__
 58   Radermacher Edgard      `RTRMKR <…>`__, `ATKRT <…>`__
 60   Radermacher Guido       `RTRMKR <…>`__, `KT <…>`__
 62   Radermacher Hedi        `RTRMKR <…>`__, `HT <…>`__
 74   Radermecker Rik         `RTRMKR <…>`__, `RK <…>`__
 66   da Vinci David          `FNS <…>`__, `TFT <…>`__
 67   van Veen Vincent        `FN <…>`__, `FNSNT <…>`__
 69   Östges Otto             `ASTJS <…>`__, `AT <…>`__
==== ======================= =========================================

Similar Clients

The test database contains a fictive person named Dorothée Dobbelstein-Demeulenaere as an example of accidental duplicate data entry. Dorothée exists 3 times in our database:

>>> for p in pcsw.Client.objects.filter(name__contains="Dorothée"):
...     print(str(p))
...
DEMEULENAERE Dorothée (23)
DOBBELSTEIN-DEMEULENAERE Dorothée (24*)
DOBBELSTEIN Dorothée (25)

The detail window of each of these records shows some of the other records in the SimilarClients table:

>>> translation.activate("en")

>>> rt.show(dupable_clients.SimilarClients, pcsw.Client.objects.get(pk=23))
`DOBBELSTEIN-DEMEULENAERE Dorothée (24*) <…>`__ Phonetic words: TMLNR, TR0

>>> rt.show(dupable_clients.SimilarClients, pcsw.Client.objects.get(pk=24))
...
`DEMEULENAERE Dorothée (23) <…>`__ `DOBBELSTEIN Dorothée (25) <…>`__ Phonetic words: TPLSTN, TMLNR, TR0

>>> rt.show(dupable_clients.SimilarClients, pcsw.Client.objects.get(pk=25))
...
`DOBBELSTEIN-DEMEULENAERE Dorothée (24*) <…>`__ Phonetic words: TPLSTN, TR0

Note how the result can differ depending on the partner. Our algorithm is not perfect and does not detect all duplicates.

Checked at input

If a user tries to create a fourth record of that person, then Lino will ask a confirmation first:

>>> data = dict(an="submit_insert")
>>> data.update(first_name="Dorothée")
>>> data.update(last_name="Dobbelstein")
>>> data.update(genderHidden="F")
>>> data.update(gender="Weiblich")
>>> test_client.force_login(rt.login('robin').user)
>>> res = test_client.post('/api/pcsw/Clients', data=data, REMOTE_USER="robin")
>>> res.status_code
200
>>> r = json.loads(res.content)
>>> print(r['message'])
There are 2 similar Clients:<br/>
DOBBELSTEIN-DEMEULENAERE Dorothée (24*)<br/>
DOBBELSTEIN Dorothée (25)<br/>
Are you sure you want to create a new Client named Mrs Dorothée DOBBELSTEIN?

This is because lino.mixins.dupable.Dupable replaces the standard submit_insert action by the CheckedSubmitInsert action.

The algorithm

The alarm bell rings when there are two similar name components in both first and last name. Punctuation characters (like “-” or “&” or “,”) are ignored, and also the ordering of elements does not matter.

The current implementation splits the name of each client into its parts, removing punctuation characters, computes a phonetic version using the NYSIIS algorithm and stores them in a separate database table.

How good (how bad) is our algorithm? See the source code of lino.projects.min2.tests.test_min2.