database - mysql key/value store problem -

i'm trying implement key/value store mysql

i have user table has 2 columns, 1 global id , 1 serialized data.

now problem everytime bit of user's data changes, have retrieve serialized data db, alter data, reserialize , throw db. have repeat these steps if there very small change of user's data (since there's no way update cell within db itself)

basically i'm looking @ solutions people use when faced problem?

maybe should preprocess json data , insert data proper mysql row separated fields.

since input json, have various alternatives converting data:

you mentioned many small changes happen in case. occur? happen in member of list? top-level attribute?

if updates occur in list members in part of json data, perhaps every member should in fact represented in different table separate rows.

if updates occur in attribute, represent field.

i think cost of preprocessing won't hurt in case.