- From: Jeremy Orlow <jorlow@chromium.org>
- Date: Thu, 31 Mar 2011 11:17:28 -0700
- To: Keean Schupke <keean@fry-it.com>
- Cc: Jonas Sicking <jonas@sicking.cc>, Joran Greef <joran@ronomon.com>, public-webapps@w3.org
- Message-ID: <BANLkTimsZzNtHzftWj2=XW3HBdbojJ=ALw@mail.gmail.com>
On Thu, Mar 31, 2011 at 11:09 AM, Keean Schupke <keean@fry-it.com> wrote: > On 31 March 2011 17:41, Jonas Sicking <jonas@sicking.cc> wrote: > >> On Thu, Mar 31, 2011 at 1:32 AM, Joran Greef <joran@ronomon.com> wrote: >> > On 31 Mar 2011, at 9:53 AM, Jonas Sicking wrote: >> > >> >> I previously have asked for a detailed proposal, but so far you have >> >> not supplied one but instead keep referring to other unnamed database >> >> APIs. >> > >> > I have already provided an adequate interface proposal for putObject and >> deleteObject. >> >> That is hardly a comprehensive proposal, but rather just one small part of >> it. >> > > I wanted to make a few comments about these points :- > > >> >> I do really think the idea of not having the implementation keep track >> of the set of indexes for a objectStore is a really interesting one. >> As is the idea of not even having a set set of objectStores. However, >> there are several problems that needs to be solved. In particular how >> do you deal with collations? >> > > no indexes, no object stores... well I for one prefer the > "validate_object_store", "validate_index" approach, in that it can hide > statefullness if necessary (like I do with RelationalDB) whilst presenting a > stateless API. It also keeps the size of the put statements down. > > >> >> I.e. we have concluded that there are important use cases which >> require using different collations for different indexes and >> objectStores. Even for different indexes attached to the same >> objectStore. >> >> Additionally, if we're getting rid of setVersion, how do we expect >> pages dealing with the (application managed) schema changing while the >> page has a connection open to the database? >> > > 1 - there is no schema > 2 - dont allow it to change whilst the database is open > > In reality a schema is implicitly tied to a code version. In other words > the source code of the application assumes a certain schema. If the assumed > schema and the schema in the DB do not match things are going to go very > wrong very quickly. Schema changes _always_ accompany code changes > (otherwise they are not schema changes just data changes). As such they > never happen when a DB is open. The way I handle this in RelationalDB, by > validating the actual schema against the source-code schema in the db-open > (actually the method is called validate), is probably the best way to handle > this. If the database does not exist we create it according to the schema. > If it exists we check it matches the schema. If there is a difference we see > if we can 'upgrade' the database automatically (certain changes like adding > a new column with a default value can be done automaticall), if we cannot > automaticall upgrade, we exit with an error - as allowing the program to run > will result in corruption of the data already in the database. At this point > it is up to the application to figure out how to upgrade the database (by > opening one database with an old schema and another with a new schema)... > There is not point in ever allowing a database to be opened with the wrong > schema. > > >> So pretty please, with sugar on top, please come up with a proposal >> for the full API rather than bits and pieces. >> >> And I should mention that I have as an absolute requirement that you >> should be able to specify collation by simply saying that you want to >> use "en-US" or "sv-SV" sorting. Using callbacks or other means is ok >> *in addition to this*, but callback mechanisms tend to be a lot more >> complex since they have to deal with the callback doing all sorts of >> evil things such as returning inconsistent results (think "return >> Math.random()"), or simply do evil things like navigate the current >> page, deleting the database, or modifying the record that is in the >> process of being stored. >> > > The core API only needs to deal with sorting binary-blob sort orders. A > library wrapper could provide all the collation ordering goodness that > people want. For example RelationalDB will have to deal with sorting orders, > it does not need the browser to provide that functionality. In fact browser > provided functionality may limit what can be done in libraries on top. > This is difficult if not impossible to do. See previous threads on the matter. J > > >> >> / Jonas >> >> > > Cheers, > Keean. > >
Received on Thursday, 31 March 2011 18:18:18 UTC