Re: How to migrate column type from uuid to serial

I was thinking UUID was not a very good choice for id. Serial would be a
better one because I don't have a billion customers. It is more like a
thousand. So when I saw the customer ID of the payment gateway cannot
accept more than 32 characters, I thought UUID is overkill. So I want to
migrate to using a serial int instead as the primary key.,

On Wed, Oct 7, 2020 at 10:48 PM Francisco Olarte <folarte(at)peoplecall(dot)com>
wrote:

> Hemil:
>
> On Wed, Oct 7, 2020 at 2:49 PM Hemil Ruparel <hemilruparel2002(at)gmail(dot)com>
> wrote:
> > I was integrating a payment gateway for my app when I noticed its
> maximum length of customer id string is 32. SIze of UUID is 36 (32
> characters and 4 dashes). So I want to change the type of customer id to
> serial. The problem is by now, the column is being used at many places. How
> to migrate the column to serial without dropping the data?
>
> An uuid is just a 128 bit number, as noted by many. Your problem is
> the default encoding is 32 hex digits plus 4 hyphens. If your payment
> gateway uses a 32 CHARs string ( "maximum length of customer id
> string is 32" ) you can just use other encodings. Passing to integer
> and using decimal wont cut it ( you'll need 39 digits ), but using
> just hex (without hyphens) will drop the string representation to 32
> characters ( you can encode with a subst and postgres accepts it
> without hyphens ).
>
> If you want to buy a little more space for your own purposes you can
> even fit 128 bits in 22 base64 chars with a couple pairs of bits to
> spare, and IIRC you can do it with a creative decode/encode step after
> killing the dashes.
>
> And if your payment gateway uses unicode codepoints instead of ASCII
> chars as units you could probably use more creative encodings ;-) ,
> but probably using a "drop the dashes" subst in the interface will be
> your simpler option.
>
> Francisco Olarte.
>