Just to pile on about how bad this is (and I know this was not your idea) starting with this sample data:

IF OBJECT_ID('dbo.table1','U') IS NOT NULL DROP TABLE dbo.table1;
IF OBJECT_ID('dbo.table2','U') IS NOT NULL DROP TABLE dbo.table2;

CREATE TABLE dbo.table1 (nameId INT IDENTITY, phoneNbr VARCHAR(20), email VARCHAR(100));
CREATE TABLE dbo.table2 (nameId INT IDENTITY, ContactInfo XML);

INSERT dbo.table1(phoneNbr,email) VALUES ('555-444-3333','JoeBlow@gmail.com');
INSERT dbo.table2(ContactInfo) VALUES 
('<contactInfo>
 <phone>555-444-333</phone>
 <email>JoeBlow@gmail.com</email>
</contactInfo>');

Note these queries:

-- relational
SELECT t.nameId, t.phoneNbr, t.email
FROM dbo.table1 AS t
WHERE t.email IS NOT NULL

-- XML:
SELECT 
  t.nameId,
  phoneNbr = t.ContactInfo.value('(contactInfo/phone/text())[1]', 'VARCHAR(20)'),
  email  = t.ContactInfo.value('(contactInfo/email/text())[1]', 'VARCHAR(100)')
FROM dbo.table2 AS t
WHERE t.ContactInfo.value('(contactInfo/email/text())[1]', 'VARCHAR(100)') IS NOT NULL;

Before considering performance, just consider how much more complicated the XML-based solution is. Which is easier to understand? Which appears easier to troubleshoot? Which structure seems easier to maintain?

Now look at the execution plans:


... and this is just one record. Imagine trying to join some other tables, adding a GROUP BY or other basic SQL. The queries will be miserably slow and impossible to tune because the execution plan becomes insanely verbose. Just more food for thought.

Don't you just have a couple articles you can point them to, Jeff? I'm sure I've seen you do this at least once, maybe in forum posts, I don't know. And again, sad I missed out on you last month, I love "beating them with their own bat".....

OMG don't get me started. NO!!! We had meetings and discussions and "understandings". I even have an email from one of the developers a couple days before this last meeting asking me at what point the tables should be populated and getting specifics on things. But then suddenly, they turned the tables (pun intended). A lot of the development they were doing they hard coded things and/or just populating this blob table as a "place holder". Place holder my butt!!! I am also appalled that they aren't following any sort of SDLC methodology... just sort of "get it done" approach. But it will be me that gets thrown under the bus when everything tanks...

Be sure that you have all your CYA documentation. I have seen that turn the bus around on the people trying to throw someone under the bus.

I actually am ok with placeholders, its sort of like "stubbing out" code but that's probably not helpful for you in any case. I do it, its a great way to get sections done in such a way to progress a project. Not saying there aren't costs but costs are ok if you can account for them via the benefits. I doubt you're interested in that discussion though, right?

I would be really interested in hearing more from your counterparts about their plans. I don't have that great interest in "sargability" posts and the like that you're seeing here because honestly anybody should be able to read on that, even your counterpart / associates. I'm interested in what your counterparts are doing, but you are sort of coloring the discussion in such a way that I think you'd be better served by just going with the "choir" you are "preaching" to and in any case you aren't obliged to serve my curiosity and that's cool!

I like what your counterpart said to you to be honest, and I'd like to hear more, but I think your posts indicate that you aren't in the mood and this isn't what you're after in this thread so for my part I'll have to let it go at that.

I will say this however, you're implying that you'll get "thrown under the bus" even when documenting your contrary indications to their plans, so can we at least be honest on this one, ie., that it isn't a technical issue? If you think you'll get adversely affected despite your best efforts isn't that really the heart of the issue?

I'd love to play devils advocate and examine your initial "list". In particular I disliked your "ACID" line item and thought it plain that it did not apply. But in explaining my thoughts I'd probably just be typing gratuitiously LOL when in reality I don't think the issue is technical at all and in any case there's plenty of other posters who can make you feel better on this one so there's that.