- From: Keean Schupke <keean@fry-it.com>
- Date: Thu, 31 Mar 2011 18:24:57 +0000
- To: Jeremy Orlow <jorlow@chromium.org>
- Cc: Jonas Sicking <jonas@sicking.cc>, Joran Greef <joran@ronomon.com>, public-webapps@w3.org
- Message-ID: <AANLkTimTgrY7LX8L6f=SF_GnAUUhCHVC1xU3Paoyt=W-@mail.gmail.com>
On 31 March 2011 18:17, Jeremy Orlow <jorlow@chromium.org> wrote: > 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 > I can find a lot of stuff on collation, but not a lot about why it could not be done in a library. Could you summerise the reasons why this needs to be core functionality for me? A library could chose to use an object store as meta-data to store the collation orders that it is using for various indexes for example. Cheers, Keean.
Received on Thursday, 31 March 2011 18:25:30 UTC