Web sql database earased when users update app from App store

I have a cordova application which uses web sql databse. Before releasing this version I have updated a table to include to new columns. When user update the APP previous data is erased. If user install a new copy it works and on updating user is unable to find any previous data.

I can't even alter the table because I don't know if user already has table or not. Currently I am using 'CREATE TABLE IF NOT EXISTS' to create a table.

var myDB = openDatabase('test', 1.0, 'Native APP', 5*1024*1024);

I have tried changing the version of the database from 1.0 to 2.0 but to no avail. Need some help!

I am surprised to see no answers to this question.So I found something Here is How you do it,

var db = openDatabase("example_db", "", "Example Database", 100000);

if(db.version == ""){
  db.changeVersion("", "1", function(t){
    t.executeSql("create table foo...");
  }, null /* error callback */, function(){
    // success callback
    db.changeVersion("1", "2", function(t){
      t.executeSql("alter table foo...");
    });    
  });
}

if(db.version == "1"){
  db.changeVersion("1", "2", function(t){
    t.executeSql("alter table foo...");
  });
}

This worked for me!