Question

I have recently seen articles on HTML5 and local Db creation and usage. I have also seen some examples of Javascript connection strings to existing Access Db backends. I am interested in finding a way to build a Db, pre-load it with records, and use a web app to connect and read the Db. For example, I have created many standalone applications with Tcl, in Windows, that read off of Sqlite Db files. Essentially, the application (.exe file) and Db file sit next to each other in a folder and function like any other Db application, except without the use of servers.

I would like to be able to do the same, but with a web app (.html) and Db file. Does anyone know if this is possible? As an example, I wanted to build a language application that runs in any browser, with pre-loaded words saved in the backend. So there would be two files, the web app, and the db file.

Any suggestions or links to resources would be really appreciated. The only thing close that I could come up with was connecting to Access via OLE through Javascript, however I need a Db that is multi-platform like Sqlite.

Thanks,

DFM

Answer 1

Your web app, its local database, and the “priming” data will all have to start somewhere, so I’ll assume this all gets rolling during a live connection to a web server. When this first hit comes in, you:

1. Deliver the page and related code.
2. In your JavaScript, test for the existence of the database.
   1. Exists? No priming necessary. Do nothing, or sync, etc.
   2. Doesn’t exist? Build it and deliver initial data. If this is slow, you can give the user a friendly warning: “Setting up, please stand by.” Depending on how you’re pushing down all that data, you might even show a progress bar: “Initializing database: 10%”…
3. There is no step 3.

Once setup is complete, this app could be entirely local — no net connection required — as long as you code it without the assumption of non-local resources.

References:

• Getting Started with HTML5 Local Databases
• Offline Web Applications in HTML5