What length should I give to a MYSQL VARCHAR field that stores a signature in JSON?

Question

I'm trying to store signatures in a database. I'm using a the signature pad plugin (signaturePad) which converts from canvas to JSON and now want to store the signature in MySQL.

I'm using a VARCHAR field, but I'm not sure which length I should allow. I tried several times and usually end up with a string between 2000 and 3000 characters.

Question:
What should I use for field length in MYSQL? I don't know how the CANVAS=>JSON conversion is done, so maybe someone can give me a pointer on what to expect?

Thanks!

You didn't see http://thomasjbradley.ca/articles/saving-signatures-php-mysql/? — Dancrumb, Oct 25 '12 at 21:04

score 4 · Accepted Answer · answered Oct 25 '12 at 21:05

4

I would not use VARCHAR, I would use TEXT. You may sacrifice performance in doing this, but you won't have to worry about size constraints.

Edit:

Also, the maximum of VARCHAR is VARCHAR(65535). Just making a note there..

answered Oct 25 '12 at 21:05

burmat

2,548
1
23
28

I can set `text` to emptry string in case no signature is supplied, can I? – frequent Oct 25 '12 at 21:14
1

Yes, you can submit '' or NULL and nothing will break – burmat Oct 25 '12 at 21:38

score 2 · Answer 2 · answered Oct 25 '12 at 21:05

2

Don't use VARCHAR. Use TEXT.

Outlined in the docs for the signaturePad plugin

answered Oct 25 '12 at 21:05

Dancrumb

26,597
10
74
130

score 2 · Answer 3 · edited May 23 '17 at 12:16

2

probably better off using one of the TEXT datatypes.

TINYTEXT    256 bytes    
TEXT    65,535 bytes    ~64kb
MEDIUMTEXT   16,777,215 bytes   ~16MB
LONGTEXT    4,294,967,295 bytes ~4GB

It also depends on your version of MySQL.

see: Is a VARCHAR(20000) valid in MySQL?

edited May 23 '17 at 12:16

Community

1
1

answered Oct 25 '12 at 21:10

djjolicoeur

484
3
7

What length should I give to a MYSQL VARCHAR field that stores a signature in JSON?

3 Answers3