Save json data in SQL lite if there is no internet connection

Ionic Framework ionic-v3
1

Hi I want to know what is the best way to save data coming from external link in json fromat
in the SQL lite database
and if there is no internet connection … the application will retrieve data from SQL database

2

Hi @aboulfotouh,

I did this for caching and works fine.

Use e.g. https://ionicframework.com/docs/native/sqlite/ to add sql support and store the json data you retreived via the http request in your local database together with an identifier (in my case the url params I use for the request).

In second step, add https://ionicframework.com/docs/native/network/ to check what kind of connection (none at all, 3G, …) you have and depending on the answer retreive the data from your database with the url params in a query to select the right local data set or get it via http.

Very minimalistic example:

if(!this.checkNetwork()){			
  this.getCacheData(params)
}else{            
    this.loadData(params);
}

checkNetwork(){
    //Uses ionic native network to check if there is a connection or not and returns true or false
}

getCacheData(params) {
    //Perform the acual database query with your params
    //Don't forget to sanitize any input before doing the acual query!!!
   //If there is no data in storage matching your params, trigger an error message your the user telling him to reload or wait a little
}

loadData(params){
    //Retreive your data via http request from your server.
    //In case the server is not available at that moment, you could implement a fallback and requesting the cached data from local storage instead.
    //In case of a successfull request, store the response in your local database for future usage
}

triggerError(){
    //Show error message if no cached data is available or data could not be loaded
}

The above example is quite simple but it should explain the general concept I think.

1 Like
3

Think about whether you really need to be interacting with SQLite. Ionic Storage is much simpler to deal with and works in browsers as well, making development much easier.

1 Like
4

thank you for the clear example
but it’s better to save the data in SQLite or caching it ?

5

As rapropos said, you could also use Ionic storage. These are the only two ways i’m aware of at the moment to effectively store your data on a device.

And regarding “it’s better to save the data in SQLite or caching it?”: Storing data localy is caching in some ways. If you make yourself independent from an internet connection with storing a server response for future use, you do cache it.

I usually use SQLite for caching content as I need it for other stuff too, but the ionic storage solution should be enough in your case i think

8

Kindly fill in sample codes for each of the functions for better understanding. Thanks.