Irrelon
DB.drop() is not actually dropping DB
Hi Irrelon,
We control stale data by date. So everytime user access our web app, we check the current date to drop DB and then create a new fresh DB.
if (current_date != localStorage.get("dbCreatedDate"){
var oldDB = FDB.db("DBName");
oldDB.on("drop", function(){
DB.save("dbVer", Config.database.version);
DB.save("dbCreatedDate", current_date);
})
FDB.db("DBName").drop();
}
var db = FDB.db("DBName"); //create new fresh one ??
When we use db to load collections, we still get the old data of collection. Could you advice us
Thanks, Karma
On github you can denote an area of code by wrapping it in three backticks ```
If you are writing js code you can format the code with three backticks and js ```js
Remember to add three backticks on a new line at the end of your code too :)
To answer your question, I believe the docs on the main page in the section: https://github.com/Irrelon/ForerunnerDB#dropping-and-persistent-storage are incorrect. You should pass true to db.drop so that it tells the db to specifically delete persistent data:
db.drop(true);
Could you try that? There are unit tests covering this exact scenario and they are passing so I'm confident it should work. If it works I will update the documentation to correctly include a boolean flag when dropping.
Thanks for your quick response. I tried db.drop(true) but when I check on Developer Tools of chrome, I can see the data in indexedDB. May it be caused by other places referring to FDB ?
Just checking you refreshed the indexedDB data (bottom left of chrome tools) after the drop?
I'm guessing you did but it doesn't refresh in realtime so worth checking before I go down the rabbit hole :)
Hi Irrelon,
Yes I refreshed the indexedDB data right after dropping DB. But I tried another way. After dropping DB, I tried to load collection again and I can found data in that collection:
db = FDB.db("DBName");
db.collection("WeeklyFollowUp").load(function(err, tableStats, metaStats){
$log.debug("loaded weekkkkk",tableStats);
});
I am using Version 1.3.867.
For your information, I am using ForerunnerDB add-on for Chrome. May it cause the issue ?
The add-on won't cause an issue, I have it too :)
If you look at the unit test that covers this functionality maybe you can spot something that is different?
Here are the lines that deal with checking a dropped database no longer contains data after a .load() call: https://github.com/Irrelon/ForerunnerDB/blob/master/js/unitTests/tests/testsPersist.js#L229-L281
I'm also running some more manual tests to see if I can identify a case where it doesn't work...
I found the difference. The unit test for this function is the intermediate logic. That means DB starts with some collections, persist then drop DB. While my case is: refreshing the webapp, FDB starts from the beginning and drop DB.
I will investigate more and let you know
Thanks
Ahh that is interesting. I will also investigate and see if I can reproduce the error based on what you've said.
Just put together this test and ran in console:
var fdb = new ForerunnerDB(),
db = fdb.db('test');
db.collection('test');
db.load(function () {
console.log('Loaded', arguments);
console.log('Current data', db.collection('test').find());
db.collection('test').insert({_id: 0, test: true});
console.log('Current data', db.collection('test').find());
db.save(function () {
console.log('Saved', arguments);
db.drop(true, function () {
console.log('Dropped');
console.log('Current data', db.collection('test').find());
// Generate a new database instance
db = fdb.db('test');
});
});
});
On refresh the data has gone from indexeddb. I am using the absolute latest build though.
I created test.html with code below:
<script type="text/javascript" src="fdb-core+persist.js"></script>
<script>
var fdb = new ForerunnerDB(),
db = fdb.db('test');
db.collection('test');
db.load(function () {
console.log('Loaded', arguments);
console.log('Current data', db.collection('test').find());
db.collection('test').insert({_id: 0, test: true});
console.log('Current data', db.collection('test').find());
db.save(function () {
console.log('Saved', arguments);
db.drop(true, function () {
console.log('Dropped');
console.log('Current data', db.collection('test').find());
// Generate a new database instance
db = fdb.db('test');
});
});
});
</script>
But there is error:
TypeError: obj.keys is not a function
$main @ fdb-core+persist.js:11999
function @ fdb-core+persist.js:11989
Overload.callExtend @ fdb-core+persist.js:10747
(anonymous function) @ fdb-core+persist.js:10681
(anonymous function) @ test.html:8
I think you need to update your forerunner to the latest version. I think this will solve your problem. Could you give it a go and let me know? :)
Firstly, I changed to new version 1.3.909. The js error go away.
Secondly, I found the problem. DB cannot be dropped/loaded without knowing in advance which collections it have. So, actually it is collection itself is dropped/loaded not the DB.
I made a test. First, I stored test collection data into indexedDB by FDB. Then, I use two testing logic below:
This code cannot drop real data in indexedDB
var fdb = new ForerunnerDB(),
db = fdb.db('test');
db.drop(true);
db = fdb.db('test');
This code can drop real data in indexedDB
var fdb = new ForerunnerDB(),
db = fdb.db('test');
db.collection('test');
db.drop(true);
db = fdb.db('test');
What I expect is FDB should be able to know which collection the DB have from indexedDB. And Whole DB should be dropped/loaded without declaring first the collections.
Hmm yes that is a very good point. I think what is missing from the persistence plugin is when it saves and loads it checks for a collection manifest so it knows ahead of time what should be loaded. It is an easy change (I think).
At least you have a fix for now. I will schedule work on the plugin to make this happen.