SP2010 JSOM: updating with CAML where clause

Question

So I learned and have used the following to update a list item by ID using Javascript Client Object Model:

function updateItem(passedID) {

var ctx = new SP.ClientContext.get_current();
var myList = ctx.get_web().get_lists().getByTitle('Example');
this.listItem = myList.getItemById(passedID);
this.listItem.set_item("Title", "different value");
this.listItem.update();
ctx.executeQueryAsnyc(Function.createDelegate(this, this.OnHooray), Function.createDelegate(this, this.onAwww));
}

function onHooray(sender, args) {
alert('hooray');
}

function onAwww(sender, args) {
alert('Awww');
}

So this is the basic idea, but I would am interested in finding out if I can apply a CAML query instead of updating by the Id in every instance. So for example if I had a ProjectID within the example list could I somehow apply this:

var proproductIDVal = "TR543A1Z";

"<Query><Where><Eq><FieldRef Name = 'ProjectID'/><Value Type='Text'>" + productIDVal + </Value></Eq></Where>"</Query>";

so that whatever Id that has a record gets updated instead of knowing (or querying for) the record Id everytime in advance? Is this is possible would and there were multiple records would that update every record that held that value?

greatly appreciated as I can't seem to find a reference to this in particular anywhere.

Answer 1

One oddity about the JSOM is that you need to wrap the CAML query in a <View> tag.

var proproductIDVal = "TR543A1Z";

var queryXml = "<View><Query><Where><Eq><FieldRef Name = 'ProjectID'/><Value Type='Text'>" + productIDVal + "</Value></Eq></Where></Query></View>";
var query = new SP.CamlQuery();
query.set_viewXml(queryXml);
var context = new SP.ClientContext.get_current();
var list = context.get_web().get_lists().getByTitle(listTitle);
var query = new SP.CamlQuery();
var items = list.getItems(query);
context.load(items);
context.executeQueryAsync(/**etc**/);

Then in your success callback you will need to take the items as a collection and loop through them.

var resultsEnumerator = items.getEnumerator();
while (resultsEnumerator.moveNext()) {
   var currentItem = resultsEnumerator.get_current();
   //Do stuff with the item and call update.
} 

//Call execute query async again, etc... 

Of course you can find plenty of examples online to get a full code example but this gives you the basics of how to do what you want.

Links: Getting List Items in JavaScript

Approve multiple documents or list items in one operation with client side code