- From: Keean Schupke <keean@fry-it.com>
- Date: Thu, 31 Mar 2011 18:54:38 +0000
- To: Jeremy Orlow <jorlow@chromium.org>
- Cc: Jonas Sicking <jonas@sicking.cc>, Joran Greef <joran@ronomon.com>, public-webapps@w3.org, Pablo Castro <Pablo.Castro@microsoft.com>
- Message-ID: <AANLkTimZ3ZbDLAVDaH6ST9Q9aiFp706m0CwPK=LkJ+9C@mail.gmail.com>
On 31 March 2011 18:36, Jeremy Orlow <jorlow@chromium.org> wrote: > On Thu, Mar 31, 2011 at 11:24 AM, Keean Schupke <keean@fry-it.com> wrote: > >> 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? >> > > Sorry, but that stuff is paged out of my brain. Pablo, can you? > > >> 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. >> >> > > Thanks would help me understand. As long as there is a way to turn default collation off and just have a binary string sort order thats fine for my needs. Cheers, Keean.
Received on Thursday, 31 March 2011 18:55:11 UTC