Is there a limit size to the field name?

[cepeti]

When creating a table i'm trying to get some fields with 27 character names or longer and they just aren't created as columns in MySQL. Here i'm trying to create a table with data from the "qual_procedimento_utilizado" field.

I confirmed this is the correct field name from the redcap API playground

Redcap-etl doesn't give any warning but it simply ignores that line entirely.

I tried changing that line to another field, and i can get it to work with fields with shorter names, but it ignored every field i tried with 27 characters or more.

I also didn't find anything about field name limit on the docs so i think this could be a bug.

[mullen2]

@cepeti I have not been able to recreate this issue. I created a REDCap project that has a field name that was 63 characters long, and REDCap-ETL successfully exported the field to MySQL.

[mullen2]

@cepeti If you can upload a small example REDCap project (without real data) and transformation rules where the problem occurs for you, I can run it on my system to see what happens.

[cepeti]

i'll give you an api key for a duplicate test project with no real data. But could it have something to do with the checkbox (multiple values) field type? I didn't see any examples with it in the docs and no mention of how it'll store it with multiple values in one MySQL column.

[mullen2]

It could have something to do with the checkbox type. For checkboxes, a field is created for each option. So if you have a "weekday" checkbox field with values and labels as follows:

• 1,Sunday
• 2,Monday
• 3,Tuesday
• 4,Wednesday
• 5,Thursday
• 6,Friday
• 7,Saturday

the following fields will be created in the database (using the checkbox values):

weekday___1, weekday___2, weekday___3, weekday___4, weekday___5, weekday___6, weekday___7

In addition, if label fields are being generated, then the following additional fields will be added:

weekday___1_label, weekday___2_label, weekday___3_label, weekday___4_label, weekday___5_label, weekday___6_label, weekday___7_label

It is possible that with the addition of the checkbox value (especially if yours are very long) and the label field suffix, the maximum size for a MySQL column name could be exceeded.

[cepeti]

I tested a transformation file with the root table having only this field and still it's not in there. It makes a table, but without that field. I tested this field with both int and string and nothing:

Here's the example so you can test it: onedrive

this folder has the transformation file and the config file, with all set to extract from a test project with no real data in it.

This is the field in the designer page:

[mullen2]

@cepeti Thanks for the information. I'm still looking into this, but I tried using type "checkbox" in the transformation rules instead of "string" for the checkbox field, and it looks like that made things work.

Change:
FIELD,qual_procedimento_utilizado,string,procedimento
to:
FIELD,qual_procedimento_utilizado,checkbox,procedimento

[cepeti]

Oh, my bad, i didn't find that in the documentation before, but i see it now right before the examples. I was mistaking the "type" in the transformation rules for MySQL types and didn't think it was a REDCap field type.

It was my mistake, but if i could add a suggestion, i think a warning would be good in cases where it doesn't generate a column for a transformation rule. Like "couldn't find a REDCap field of type [type] named [name], skipped column"