There is a lot of confusion when it comes to ionic 2 storage. There was a lot of changes in the new ionic version as Storage was moved to #ionic/strage . I am new to Ionic so some of the things are confusing for me. I have web-development background. From the documentation,
A simple key-value Storage module for Ionic apps based on LocalForage,
with out-of-the-box support for SQLite. This utility makes it easy to
use the best storage engine available without having to interact with
it directly. Currently the ordering is SQLite, IndexedDB, WebSQL, and
LocalStorage.
Installation
npm install #ionic/storage
If you'd like to use SQLite as a storage engine, install a SQLite plugin (only works while running in a simulator or on device):
cordova plugin add cordova-sqlite-storage --save
What I would like to know is, what happens when I run this in browser ? Where does it store the data? What would happen if I dont use cordova-sqlite-storage ? Where does it store the data then?
Ionic also supports SQLite plugin natively to store data in SQLite database .
import { SQLite } from 'ionic-native'
How is it different from Storage other than the fact that there is a fallback to IndexedDB, WebSQL, and LocalStorage ?
I hope my thoughts are in the right direction. A clear answer on how these modules work would be really helpful.
Ionic Storage is the first module written with proper web fallback in mind.
One near-term goal we have with Ionic is enabling devs to build 99% of their app in the browser. It's a much faster workflow. This means support for native plugins that have web fallbacks, as well as better mocking for ones that don't. - Max Lynch on Twitter
By default when running, #ionic/storage will prioritize the storage methods this way:
When running in a native app context, Storage will prioritize using
SQLite, as it's one of the most stable and widely used file-based
databases, and avoids some of the pitfalls of things like localstorage
and IndexedDB, such as the OS deciding to clear out such data in low
disk-space situations.
When running in the web or as a Progressive Web App, Storage will attempt to use IndexedDB, WebSQL, and localstorage, in that order.
- Official Documentation
So when your app is running in the browser (or on a device without the SQLite plugin) it will detect that SQLite is not available and will use IndexedDB/WebSQL instead.
How is it different from Storage other than the fact that there is a fallback to IndexedDB, WebSQL, and LocalStorage?
The SQLite plugin gives you low-level access to an SQLite database, which means you have to care about creating/updating your schemas, and write queries.
#ionic/storage is a wrapper which abstract away the differences of LocalForge and SQLite and provide a simple, unified API to store key/value pairs.
Also it takes care of serializing/deserializing of your objects.
From my understanding of the Ionic 2 RC Storage module, when you are running in the browser you are now only able to store key-value pairs (LocalStorage). You are currently not able to store anything more than that, so you should check out other options like PouchDB and LocalForage if you need full SQL support. This definitely isn't ideal for progressive web apps.
Pardon if this sounds noob.
We are current working on a mobile application that utilizes the Cordova framework. We would need to store data on the device, and such had decided on to use a database system.
We understand that for db storage, Cordova supports the WebSQL API, but since currently W3C stopped the development on WebSQL, we would wish to use a native SQLite database.
However, we do have a database file that are created via the WebSQL API. I understand that WebSQL actually utilize SQLite underneath(correct me if i'm wrong), but would the file display the characteristic of a WebSQL database? such as the file size limitation on mobile device?
The file size limitation is implemented in the particular copy of the SQLite library that is used to access the database, not in the database file itself.
Please note that W3C's (lack of) endorsement does not necessarily influence whether Cordova continues to use WebSQL.
What is the safest way to store offline data that can be synchronized with a remote Sql Server if we build an app using Xamarin on IPhone?
We are currently investigating SiaqoDB and Sqlite.
SiaqoDB does have samples for this, however, the database itself seems somewhat unknown and the community around it is small.
Sqlite has a huge userbase but there don't seem to be any out of the box sync support for this.
Are there other alternatives?
How does SiaqoDB compare to Sqlite here?
I dont know SiaqoDB but i used SQLite on a Xamarin project a while ago.. If you use the SQLite component from Krueger systems Krueger you will have a working database, without synchronization. You could also go for Zumero SQLite, which includes synchronization to their own server, but i haven´t tried them so i cant compare the two.
I'm building an app that will grab a content from some CMS, and save it in the phone.
Usually I do that using IsolatedStorageSettings. Is there any reason why would I use the SQLlite instead?
Why you need to use SQLite; MS doesn't have direct support to SQLite. You can use SQLCE for your application instead. Simply the usage of Isolated Storage is not appreciable if you are using a huge chunk of structured data. Still you decide to use ISO for storing i am sure definitely you will face issue in future. Probably the areas like Tombstoning, FAS etc where yo may take a lots of time for saving your data to files
I don't know how authoritative this is but I found this:
http://www.sqlite.org/cvstrac/wiki?p=PerformanceConsiderations
and it doesn't seem good to have a lot of connections to sqlite. This seems to be bad for the web and most applications that have more than a few users. I'm having a hard time thinking of what sqlite would be used for when you don't need that many connections. Every program I can think of needs users, lots of them sometimes, so what would I use a database for that doesn't allow that many connections? I thought about prototypes but why would I use that when I can just connect to a larger database? Embedded apps maybe?
Thank you.
EDIT: Thanks everyone. I look at the page recommended below but an confused about something:
Under appropriate uses for sqlite it has:
Situations Where SQLite Works Well
•Websites
SQLite usually will work great as the database engine for low to medium traffic websites (which is to say, 99.9% of all websites). The amount of web traffic that SQLite can handle depends, of course, on how heavily the website uses its database. Generally speaking, any site that gets fewer than 100K hits/day should work fine with SQLite. The 100K hits/day figure is a conservative estimate, not a hard upper bound. SQLite has been demonstrated to work with 10 times that amount of traffic.
Situations Where Another RDBMS May Work Better
•Client/Server Applications
If you have many client programs accessing a common database over a network, you should consider using a client/server database engine instead of SQLite. SQLite will work over a network filesystem, but because of the latency associated with most network filesystems, performance will not be great. Also, the file locking logic of many network filesystems implementation contains bugs (on both Unix and Windows). If file locking does not work like it should, it might be possible for two or more client programs to modify the same part of the same database at the same time, resulting in database corruption. Because this problem results from bugs in the underlying filesystem implementation, there is nothing SQLite can do to prevent it.
A good rule of thumb is that you should avoid using SQLite in situations where the same database will be accessed simultaneously from many computers over a network filesystem.
The Question:
I'm going to show my ignorance here but what is the difference between these two?
This is answered well by sqlite itself : Appropriate use of sqlite
Another way to look at SQLite is this:
SQLite is not designed to replace Oracle. It is designed to replace fopen().
It's good for situations where you don't have access to a "real" database and still want the power of a relational db. For example, Firefox stores a bunch of information about your settings/history/etc in an SQLite database. You can't expect everyone that runs firefox to have MySQL or postgre installed on their machine.
It's also perfectly capable of running relatively-low traffic, read-heavy websites. The performance of it is overall very good, it's more than the large majority of websites need for their traffic levels.
It's often used for embedded applications.
It can be very handy to use a database like storage when you have no access to a database service. So SQLite is used since it's just a file you store somewhere.
I also find that using SQLite is good for getting a prototype application together pretty quickly without the overhead of having a seperate DB server or bogging a development environment with an instance of MySQL/Oracle/Whatever.
Also easy to pick up and move the database to a different machine if you need to.
The iPhone uses it for call history, SMS messages, contacts, and other type of data. Like Ólafur Waage said, good for embedded applications on mobile device because it's lightweight. I have used it also on stand alone applications. Easy to use and available on most platforms.
Think about simple client or desktop apps that could make use of a db, like as a poor example, an address book. Rather than bundling a huge db engine like mysql or postgre with your deliverable, sqlite is very lightweight and easy to include with your finished app.
This FLOSS Weekly podcast episode talks with the creator of SQLite and covers among other things goes over the type of things you would use it for. Everything from file systems for mobile phones to smallish web sites.
In the simplest terms, SQLite is a public-domain software package that provides a
relational database management system, or RDBMS. Relational database systems are
used to store user-defined records in large tables. In addition to data storage and management,
a database engine can process complex query commands that combine data
from multiple tables to generate reports and data summaries. Other popular RDBMS
products include Oracle Database, IBM’s DB2, and Microsoft’s SQL Server on the
commercial side, with MySQL and PostgreSQL being popular open source products.
The “Lite” in SQLite does not refer to its capabilities. Rather, SQLite is lightweight
when it comes to setup complexity, administrative overhead, and resource usage.
For detail info and solution about SQLite visit the link below:
http://blog.developeronhire.com/what-is-sqlite-sqlite/
Thank you.
What the above two answers say. Expanding slightly on Chad Birch's answer, its teh calls to the SQLite db, and a rather poor implementation of sync() that causes FF3 to be so slow in linux.