How much can SQLite store on the iPhone?

问题:

I have an idea for a webapp for the iPhone but its unknown to me how much data can be stored in mobile Safari's SQLite db. I tried searching through the Apple docs but found nothing:

Safari Client-Side Storage and Offline Applications Programming Guide: Using the JavaScript Database

回答1:

It's as the other posters say. You're only limited by the drive space on the device.

You also need to consider your in memory footprint though. There is a finite amount of memory on the iphone, and in general it's quiet small, so the amount of data/hydrated objects you'll be able to have in memory is another potential limitation for your app.

回答2:

Most of these answers are totally wrong. Safari will not allow you to create SQLite databases over 50MB (or expand existing databases beyond that size).

This is a limit imposed by Safari - as other people have noted, SQLite itself supports much larger databases that you can use from native apps. But webapps are limited to 50MB.

It might be useful to note that this is per database - if you really need the extra space, you can create multiple databases, although this would obviously cause a lot of hassle.

回答3:

There are a LOT of people answering that have clearly never tested it. I am on the latest version of iOS (4.3.3) and have set up a system to create multiple databases and keep them under 45 MB but found that the 50 MB cap is for the site as a whole. So, no matter how much you split the data up, it still restricts it to an aggregated cap of 50 MB.

回答4:

The database size limit on safari mobile, is 50 mb per site not per database. i have tested this. even if you have an extra empty database you cannot add to it if the total size of all databases on a single site is 50 mb

whats worth noting as well is that characters are saved as double bytes on websql, that is 2 million characters will be 4 megabytes not 2 megabytes on disk.

回答5:

You are only limited by the amount of free space on the device.

回答6:

I'm not sure. If you were doing your own application you'd be limited by free space on the device and to some extent in memory footprint (as Bryan McLemore points out).

However since you're looking at using JavaScript inside of Safari there's no easy way to tell. According to the document you found it looks like it may be limited by site, but there's nothing telling you how much. I'd suggest writing a quick script to fill up the database and figure out how much it actually is. After that, I'd probably halve that value and assume I'd be always be able to use that much.

Be sure to report back so we'll all know!

回答7:

It's most likely 32 terabytes... which is well over the available disk space.

I reached this number by multiplying the maximum page size by the maximum page count listed at the bottom of the SQLite limits page.

回答8:

Limits In SQLite

"Limits" in the context of this article means sizes or quantities that can not be exceeded. We are concerned with things like the maximum number of bytes in a BLOB or the maximum number of columns in a table.

SQLite was originally designed with a policy of avoiding arbitrary limits. Of course, every program that runs on a machine with finite memory and disk space has limits of some kind. But in SQLite, those limits were not well defined. The policy was that if it would fit in memory and you could count it with a 32-bit integer, then it should work.

Unfortunately, the no-limits policy has been shown to create problems. Because the upper bounds were not well defined, they were not tested, and bugs (including possible security exploits) were often found when pushing SQLite to extremes. For this reason, newer versions of SQLite have well-defined limits and those limits are tested as part of the test suite. As of version 3.6.19 (all statistics in the report are against that release of SQLite), the SQLite library consists of approximately 65.7 KSLOC of C code. (KSLOC means thousands of "Source Lines Of Code" or, in other words, lines of code excluding blank lines and comments.) By comparison, the project has 690 times as much test code and test scripts - 45409.7 KSLOC.

回答9:

The default storage limit on iPhone seems to be 5mb

回答10:

davibe has done some work to raise the limit up to 1GB with his PhoneGap plugin. https://github.com/davibe/Phonegap-SQLitePlugin

The plugin calls the native sqlite3 API, with a wrapper on the Javascript side.
The relevant code extracted from sqlite.js are:

update origins set quota = '999999999999' where origin = 'file__0';   
"update databases set estimatedSize = '999999999999' where name = '" + dbName + "';'";

回答11:

Caution: my iphone is jailbroken! But I don't suspect that this changes anything.

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The limit of 50MB is no longer correct.

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On my iPhone 4S with iOS 6.1 I have a database of 58.66 MB (448496 records) for my webclip (website pinned to the springboard).

No special tricks, just standard HTML5 usage.

回答12:

Maximum Database Size

Please refer Official Sqlite site

Every database consists of one or more "pages". Within a single database, every page is the same size, but different database can have page sizes that are powers of two between 512 and 65536, inclusive. The maximum size of a database file is 2147483646 pages. At the maximum page size of 65536 bytes, this translates into a maximum database size of approximately 1.4e+14 bytes (140 terabytes, or 128 tebibytes, or 140,000 gigabytes or 128,000 gibibytes).

This particular upper bound is untested since the developers do not have access to hardware capable of reaching this limit. However, tests do verify that SQLite behaves correctly and sanely when a database reaches the maximum file size of the underlying filesystem (which is usually much less than the maximum theoretical database size) and when a database is unable to grow due to disk space exhaustion.