Bundled the tiles into SQLite (I was inspired by seeing Dr. Hipp speak at a conference) and voila, things both easy to move and to checksum. Tiles were identified by X & Y offset at a given (Z)oom level, which made for super easy indexing in a relational DB like SQLite. On the iPad, it was then easy to give map bundles an application icon, associated datatype from file extension, metadata in a table, etc. At the time, I was fairly intimidated by the idea of creating a file format, but databases, I knew. And then making some CLI tools for working with the files in any language was trivial after that.
SQLite is very simple, yet very reliable and powerful. Using SQLite as file format might be the best decision an engineer can take when it comes to future-proofing preservation of data.
- https://github.com/rumca-js/Internet-Places-Database
For UI I use HTML, because it already provides components with bootrap, and everybody can use it without installation of any software.
All data comes from a single SQLite that is easy read, and returns data.
My database is really big, so it takes time to browse it, I wanted to provide more meaningful way to limit scope of searching
I always wonder when people can sell ideas or products so effectively.
There's always the lazy approach of storing JSON blobs in TEXT fields, but I personally shy away from that because you lose out on a huge part of the benefits of using a SQL DB in the first place, most importantly migrations and querying/indexing.
Naively, most data looks hierarchical and the instinctive reaction is to make your file format match. But if you think of this as a set of documents stacked on top of each other if you take the data as a bunch of 90 degree slices down through the stack now your data is relational, you loose the nice native hierarchical format, but you gain all sorts of interesting analysis and extraction options.
It is too bad relational data types tend to be so poorly represented in our programming languages, generally everything has to be mapped back to a hierarchical type.
Maybe a very simple document oriented db would have been better?
My biggest gripe is that the sqlite cli is brutally minimal (makes sense given design), but I probably should have been using a nicer cli.
My issue with SQLite's JSON implementation is that it cannot index arrays. SQLite indexes can only contain a single value per row (except for fulltext indexes but that's not what I want most of the time). SQLite has nothing like GIN indexes in Postgres.
Also, another usecase is to export data from production to uat for testing some scenarios, it can be easily encoded in a sqlite file.
- files can be individually extracted, in any order, from the archive
- thousands of implementations available, in every language and every architecture. no more than 32KiB RAM needed for decompression
- absolutely no possibility of patent challenges
Any multi-file archive format would do, but ZIP is very portable and random access.
If you don't need any table/relational data and are always happy to rewrite the entire file on every save, ZIP is a perfectly fine choice.
It's easier than e.g. a SQLite file with a bunch of individually gzipped blobs.
Alternatively, he could mean that, for the purposes of archiving, ZIP is very far behind the state of the art (no solid compression, old algorithms, small windows, file size limits without the ZIP64 extensions, and so on, most of which are not relevant to using ZIP as a container format)
I’ve reached for ZIP for application containers because it’s really easy, not because of design choices that affect me. Typically the compression is a convenient byproduct but not a requirement, and file size limits could be an issue, perhaps, but isn’t something I’ve ever hit when using ZIP for application data. File size limits is something I’ve hit when trying to archive lots of files.
Using ZIP for build pipelines that produce a large number of small files is handy since it’s often faster than direct file I/O, even on SSDs. In the past was much faster than spinning media, especially DVDs. These days in Python you can unzip to RAM and treat it like a small file system - and for that file size limits aren’t an issue in practice.
zip is used for Java jar files, OpenOffice documents and other cases.
The benefit is that individual files in the archive can be acces individually. A tgz file is a stream which can (without extra trickery) only be extracted from begin to end with no seeking to a specific record and no way to easily replace a single file without rewriting everything.
tgz is good enough for distributing packages which are supposed to be extracted at once (a software distribution)
CREATE TABLE image_attributes ( name text, value blob);
CREATE TABLE layers (id text, parent_id text, sequence integer, uti text, name text, data blob);
CREATE TABLE layer_attributes ( id text, name text, value blob);
> and is backwards compatible to its inception in 2004 and which promises to continue to be compatible in decades to come.
That is pretty amazing. You could do a lot worse.
Doesn't mean that whatever the app stores inside will remain backward compatible which is the harder problem to solve.