1

I've run into an interesting issue with some databases I've inherited, and could use some help unpacking it all.

The Issue

After adding a column to a table, views selecting * from that table are now breaking in strange ways. The best way for me to illustrate is to repro it, so here goes.

Repro

Here's my table definitions:

CREATE TABLE TestTable1 (
    col1 INT,
    col2 varchar(12)
)

CREATE TABLE TestTable2 (
    col3 INT,
    col4 varchar(12)
)

And some test data:

INSERT INTO TestTable1 VALUES
  (1,'abc')
, (2,'def')
, (3,'ghi')
, (4,'jkl')

INSERT INTO TestTable2 VALUES
  (1,'ABC')
, (2,'DEF')
, (3,'GHI')
, (4,'JKL')

Now the View definition (and yes I know views should have an explicit column set. Whoever wrote this one did not):

CREATE VIEW TestView AS

SELECT 
    tt1.*
    , tt2.col4
FROM TestTable1 AS tt1
INNER JOIN TestTable2 AS tt2
ON tt1.col1 = tt2.col3
GO

As you'd expect, this is the result when I SELECT * FROM TestView:

col1        col2         col4
----------- ------------ ------------
1           abc          ABC
2           def          DEF
3           ghi          GHI
4           jkl          JKL

Super sensible. Here's where it runs off the rails - I add a column to TestTable1:

ALTER TABLE TestTable1
ADD col5 varchar(8)

And having done so, here's what the view now returns:

col1        col2         col4
----------- ------------ --------
1           abc          NULL
2           def          NULL
3           ghi          NULL
4           jkl          NULL

Because of course it does. However, if I run the same query used to define the view, I get:

col1        col2         col5     col4
----------- ------------ -------- ------------
1           abc          NULL     ABC
2           def          NULL     DEF
3           ghi          NULL     GHI
4           jkl          NULL     JKL

Which is exactly what I'd expect. So what's happened? I've tried every method I can find to query the view definition to see what's changed:

SELECT VIEW_DEFINITION FROM information_schema.views WHERE TABLE_NAME = 'TestView'

EXEC sp_helptext 'TestView'

SELECT definition 
FROM sys.objects AS o
JOIN sys.sql_modules m ON m.object_id = o.object_id
WHERE o.object_id = object_id( 'dbo.TestView')
  and o.type      = 'V'

And each one returns the definition exactly as it was originally defined. It's not until I use the SQL Server Management Studio Design tool that I see something different:

SELECT        tt1.col1, tt1.col2, tt1.col5 AS col4, tt2.col4
FROM            dbo.TestTable1 AS tt1 INNER JOIN
                         dbo.TestTable2 AS tt2 ON tt1.col1 = tt2.col3

It's the work of a lunatic. It's easily fixed by updating the view to use explicit columns rather than the wildcard *. However, what I'm seeing is that this database and table are referenced in myriad views across multiple databases.

The Question

So my question is thus - where is the metadata/definition for this nonsensical version of the view, and why does it trump what is supposedly the unambiguous definition of the view?

2

The view will run according to it's metadata, which is no longer correct.

If you run sp_refreshview, it should work correctly.

sp_refreshview  @viewname =  'TestView' ;

select * from TestView ;

+------+------+------+------+
| col1 | col2 | col5 | col4 |
+------+------+------+------+
|    1 | abc  | NULL | ABC  |
|    2 | def  | NULL | DEF  |
|    3 | ghi  | NULL | GHI  |
|    4 | jkl  | NULL | JKL  |
+------+------+------+------+

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