level-atomic-data

level-atomic-data.js

//datomic clone
var log = db.sublevel('log')
var audit = db.sublevel('audit')
//var sha1sum = require('sha1sum')
//initialize current sha

db.pre(function (op, add) {
  var ts = timestamp() //or get timestamp from a transactor service
  //save this value at this timestamp.
  add({
    key: op.key + '!' + ts,
    value: op.value,
    prefix: log
  })
  //also, save a log that this key was updated at this time
  //maybe also track who did it, and maybe include the hash of the previous ts
  //which would make it impossible to insert fake old records
  add({
    key: ts, value: op.key, prefix: audit
  }
})

/*

put KEY VALUE -> 
  KEY -> VALUE             //latest value is stored without timestamp, for fast access.
  KEY : timestamp -> VALUE //can check out records at any timestamp
  timestamp -> KEY         //can read what was updated at which timestamp


normally, you retrive data like this:

*/
db.get(key, function (err, value) {

})

/*
but if you want to get data from a particular timestamp
use `level-peek` to get the last item in the range,
for that key:
*/
var peek = require('level-peek')

peek.last(log, key+'!'+timestamp, function (err, val) {
  
})