Hy there,
I can't find enough beginner resources on the web about HTML5 database storage usage examples (CRUD)
I'm opening(creating) my DB like this:
var db; $(document).ready(function() { try { if (!window.openDatabase) { alert('Not Supported -> Please try with a WebKit Browser'); } else { var shortName = 'mydatab'; var version = '1.0'; var displayName = 'User Settings Database'; var maxSize = 3072*1024; // = 3MB in bytes 65536 db = openDatabase(shortName, version, displayName, maxSize); } } catch(e) { if (e == 2) { alert("Invalid database version."); } else { alert("Unknown error "+e+"."); }return; } });
QUESTION 1: How many databases can i create and use on one domain? QUESTION 2. How to delete (drop) a database. -> i have not figured this out yet.
To create sql queries you use transaction:
function nullDataHandler(transaction, results) { } function createTables(db) { db.transaction(function (transaction) { //first query causes the transaction to (intentionally) fail if the table exists. transaction.executeSql('CREATE TABLE people(id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL DEFAULT "John Doe", shirt TEXT NOT NULL DEFAULT "Purple");', [], nullDataHandler, errorHandler); }); }
QUESTION 3: How so is the above transaciton failed if a table exists? Is the nullDataHandler involved to do this? Where on the web is there documentation explaining the executeSql API? Arguments?
thx
Advertisements. The Web SQL Database API isn't actually part of the HTML5 specification but it is a separate specification which introduces a set of APIs to manipulate client-side databases using SQL.
One of the HTML 5 specifications, Web SQL database, enables offline data storage by defining an API for storing structured data within the client. Yuvarani Meiyappan introduces the new Web SQL database feature in HTML5 and its API, and then dives into using Web SQL database with a demo for implementing a shopping cart.
The spec you're looking for is Web SQL Database. A quick reading suggests:
HTML5 Doctor also has a good introduction.
Going forward, though, I'd recommend looking at Indexed DB. Web SQL has essentially been abandoned since there is no standard for SQL / SQLite. Even Microsoft has endorsed Indexed DB. See Consensus emerges for key Web app standard.
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