Serious bug with field type changes.

[Jon_Stephenson]

I have tried to contact AirTable support, but can get no response from them so I will post this here.

Airtable has a very nasty bug if you change a text field containing a large numeric value to a number (integer) field, it changes the data values.  The attached video shows two fields, the left one is a TEXT field, the right field is just a copy of the left for reference.

In the video you will see me change the type of the left field from TEXT to NUMERIC (integer) - See that this changes every value in the field with no warning at all.  I am guessing that it only does this on large numbers, I have not tested further.

[Sho]

Oh, I see that Airtable cannot handle numbers with more than 16 digits.
Excel seems to have 15 digits.
I didn't notice that because I didn't use such large numbers.

[Alexey_Gusev]

That question discussed from time to time, here for example. Not a bug, and not Airtable-specific, rather standard data type limitation.
TL;DR: the “number” type cannot safely represent integer values larger than (2^53-1) (that’s 9007199254740991 (15 digits)), or less than -(2^53-1) for negatives.

[Jon_Stephenson]

That is all well and good if you are technical and know this sort of thing (I suggest that very few people do), but numeric fields are often used for product codes, serial numbers, bar code data , which can easily be > 16 chars.

No databases should change data en masse without a clear warning.  if this is a technical limitation then Airtable should implement a block on changing text fields with data > 16 chars (or whatever) to numeric or at the very least warn the user performing the operation.