问题
I'm using the Ethereum api. I want to store the information from the api into a mysql table.
The address data looks like:
0x3f5ce5fbfe3e9af3971dd833d26ba9b5c936f0be
0x1d80982502f3bb75654df13aa32bbd5ac9cab7d6
0xaf13bbdbe1ff53c2df7109a53c217320d2d76ee2
...
I've been using just varchar column for these characters. Are there a better data type? I'm thinking maybe varbinary but I don't know if there's any advantages. The disadvantage is that the sql code will be messier as I will have to HEX() and UNHEX().
回答1:
For me no specific type exists, you need to choose between text and binary :
CHAR(40) : (charset is not important here)
- pros : simplicity
- cons : you need more space disk (~+100%)
- cons : you risk to store invalid
non hexadata
BINARY(20) :
- pros : reduce space disk
- pros : you can't store invalid data
- cons: you need to convert (if you need see hexa value)
For me data consistency is the most important point : I prefer binary option.
- unhex('FF') == unhex('ff') but 'FF' <> 'ff'
- trying to store unhex('zz') raises an error, with text no error raised)
Moreover Hex/unHex are very simple function
Hint : You can store your data in BINARY column and create an hexa view to see easily hexa value.
Here is an example to store data in binary zone http://rextester.com/SEV11235
回答2:
Advantage CHAR: simplicity.
Advantage BINARY: you save 22 bytes per row.
In my opinion, the complexity increase isn't worth the space saving unless you're looking at a minimum of million-row databases. Even then I probably wouldn't bother.
In either case, if you care that much you can save a byte or two (and possibly improve your DB structure optimization) by using a fixed-length column rather than variable.
来源：https://stackoverflow.com/questions/47166199/best-datatype-to-store-hexidecimal-and-hex-characters-in-the-database