Problem with HOST_NAME Function with Linked View

I have an Access 2000 MDB file with a SQL 7 back end. I have a main table
with 50,000 records; and I have a selections table with 50,000 records for
each machine that uses the database (about 25-50). This allows each user to
have their own set of selections.
The selections table has three fields: ID (int), Sel (bit), MachName
(varchar). ID and MachName comprise the primary key.
I have a view that combines the main table and the entries for the
selections table for the current machine (SQL below). The view works fine
when opened in EM and QA. And if I create a pass-through query from my
Access MDB file, the results are displayed fine.
However, if I link the view to the Access MDB file, I get "#Deleted" in
every field of every record (which seems to indicate that the records were
there and then they were gone). However, if I hard-code the machine name
into the same view instead of using HOST_NAME and then relink the view to
the MDB file, the linked view opens fine. Only when I use HOST_NAME as a
parameter in the view is there a problem with it.
Anyone have any idea what's going on here, or have heard of any issues with
HOST_NAME and ODBC linked objects? SQL for the view is below.
Thanks!
Neil
SELECT INVTRY.*, InvtrySelections.Sel, InvtrySelections.MachName
FROM dbo.INVTRY INNER JOIN
dbo.InvtrySelections ON
dbo.INVTRY.ID = dbo.InvtrySelections.ID
WHERE (dbo.InvtrySelections.MachName = HOST_NAME())
Neil wrote:

> I have a view that combines the main table and the entries for the
> selections table for the current machine (SQL below). The view works fine
> when opened in EM and QA. And if I create a pass-through query from my
> Access MDB file, the results are displayed fine.
HOST_NAME() is a T-SQL function. Enterprise Manager, Query Analyzer and
Access Pass-Through querys are direct interfaces to SQL Server and thus
T-SQL

> However, if I link the view to the Access MDB file, I get "#Deleted" in
> every field of every record (which seems to indicate that the records were
> there and then they were gone). However, if I hard-code the machine name
> into the same view instead of using HOST_NAME and then relink the view to
> the MDB file, the linked view opens fine. Only when I use HOST_NAME as a
> parameter in the view is there a problem with it.
Does this not imply that T-SQL cannot construct HOST_NAME() from
Access/Jet SQL?
|||First, you shouldn't crosspost to newsgroups not relevant to your problem.
Second, create a view that will simply select and display the value of
HOST_NAME() and you will you see if there is a problem with it and
SQL-Server 7 and a MDB file.
Sylvain Lafontaine, ing.
MVP - Technologies Virtual-PC
E-mail: http://cerbermail.com/?QugbLEWINF
"Neil" <nospam@.nospam.net> wrote in message
news:lra9f.1731$8c5.1137@.newsread3.news.pas.earthl ink.net...
>I have an Access 2000 MDB file with a SQL 7 back end. I have a main table
>with 50,000 records; and I have a selections table with 50,000 records for
>each machine that uses the database (about 25-50). This allows each user to
>have their own set of selections.
> The selections table has three fields: ID (int), Sel (bit), MachName
> (varchar). ID and MachName comprise the primary key.
> I have a view that combines the main table and the entries for the
> selections table for the current machine (SQL below). The view works fine
> when opened in EM and QA. And if I create a pass-through query from my
> Access MDB file, the results are displayed fine.
> However, if I link the view to the Access MDB file, I get "#Deleted" in
> every field of every record (which seems to indicate that the records were
> there and then they were gone). However, if I hard-code the machine name
> into the same view instead of using HOST_NAME and then relink the view to
> the MDB file, the linked view opens fine. Only when I use HOST_NAME as a
> parameter in the view is there a problem with it.
> Anyone have any idea what's going on here, or have heard of any issues
> with HOST_NAME and ODBC linked objects? SQL for the view is below.
> Thanks!
> Neil
> SELECT INVTRY.*, InvtrySelections.Sel, InvtrySelections.MachName
> FROM dbo.INVTRY INNER JOIN
> dbo.InvtrySelections ON
> dbo.INVTRY.ID = dbo.InvtrySelections.ID
> WHERE (dbo.InvtrySelections.MachName = HOST_NAME())
>
|||Neil (nospam@.nospam.net) writes:
> SELECT INVTRY.*, InvtrySelections.Sel, InvtrySelections.MachName
> FROM dbo.INVTRY INNER JOIN
> dbo.InvtrySelections ON
> dbo.INVTRY.ID = dbo.InvtrySelections.ID
> WHERE (dbo.InvtrySelections.MachName = HOST_NAME())
Now that I see the entire view, I repeat what I said before: make
MachName nvarchar, and put the clustered index on this column.
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se
Books Online for SQL Server SP3 at
http://www.microsoft.com/sql/techinf...2000/books.asp
|||Ananda Sim (AnandaSim@.gmail.com.invalid) writes:
> Does this not imply that T-SQL cannot construct HOST_NAME() from
> Access/Jet SQL?
Indeed, the host name must be set through the connection string. I don't
know how it works through Access, but the mechanism is such that the
client tells SQL Server about the name, and lie as much as it want.
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se
Books Online for SQL Server SP3 at
http://www.microsoft.com/sql/techinf...2000/books.asp
|||Neil wrote:
> I have an Access 2000 MDB file with a SQL 7 back end. I have a main table
> with 50,000 records; and I have a selections table with 50,000 records for
> each machine that uses the database (about 25-50). This allows each user to
> have their own set of selections.
> The selections table has three fields: ID (int), Sel (bit), MachName
> (varchar). ID and MachName comprise the primary key.
> I have a view that combines the main table and the entries for the
> selections table for the current machine (SQL below). The view works fine
> when opened in EM and QA. And if I create a pass-through query from my
> Access MDB file, the results are displayed fine.
> However, if I link the view to the Access MDB file, I get "#Deleted" in
> every field of every record (which seems to indicate that the records were
> there and then they were gone). However, if I hard-code the machine name
> into the same view instead of using HOST_NAME and then relink the view to
> the MDB file, the linked view opens fine. Only when I use HOST_NAME as a
> parameter in the view is there a problem with it.
> Anyone have any idea what's going on here, or have heard of any issues with
> HOST_NAME and ODBC linked objects? SQL for the view is below.
I've not had any problems with Host_name() as a parameter, as the only
records I retrieve are for my particular machine there is very little
point in returning that column so I never ask the server for it as I
know the value already.
A couple of things you need to know about Access and SQL Server, firstly
bit fields should be made NOT NULL and default to 0 as Access interprets
these as Jet Yes/No columns and treats them accordingly so it expects a
value to be there (In Access/Jet, a Yes/No column cannot be null and
defaults to 0). The results otherwise can be unpredictable.
Secondly, if you have any floating point columns in your data (including
datetime as these are stored as floating point numbers) then you most
probably need a timestamp column as floating point errors can cause the
#Deleted condition you describe.
|||Hello, everyone.
I've made some progress with this strange situation. I played around with
different scenarios of the view with HOST_NAME that won't work when linked
to the MDB file, removing most fields, trying just one table, then the
other, and kept getting the "#Deleted" results. However, I found then when I
didn't assign a logical primary key when I linked the view, the results
displayed fine!
That only makes the situation stranger. But there it is.
In another post here I noted that I had created a test table with a
two-field PK, one of which contained the HOST_NAME value, and created a view
which returned records from this test table, with HOST_NAME() as a parameter
for that field. When I linked that view to the MDB file, selecting the two
PK fields as the logical primary key, it worked fine. So it's not all
logical primary keys that it has problems with.
Neil
"Neil" <nospam@.nospam.net> wrote in message
news:lra9f.1731$8c5.1137@.newsread3.news.pas.earthl ink.net...
>I have an Access 2000 MDB file with a SQL 7 back end. I have a main table
>with 50,000 records; and I have a selections table with 50,000 records for
>each machine that uses the database (about 25-50). This allows each user to
>have their own set of selections.
> The selections table has three fields: ID (int), Sel (bit), MachName
> (varchar). ID and MachName comprise the primary key.
> I have a view that combines the main table and the entries for the
> selections table for the current machine (SQL below). The view works fine
> when opened in EM and QA. And if I create a pass-through query from my
> Access MDB file, the results are displayed fine.
> However, if I link the view to the Access MDB file, I get "#Deleted" in
> every field of every record (which seems to indicate that the records were
> there and then they were gone). However, if I hard-code the machine name
> into the same view instead of using HOST_NAME and then relink the view to
> the MDB file, the linked view opens fine. Only when I use HOST_NAME as a
> parameter in the view is there a problem with it.
> Anyone have any idea what's going on here, or have heard of any issues
> with HOST_NAME and ODBC linked objects? SQL for the view is below.
> Thanks!
> Neil
> SELECT INVTRY.*, InvtrySelections.Sel, InvtrySelections.MachName
> FROM dbo.INVTRY INNER JOIN
> dbo.InvtrySelections ON
> dbo.INVTRY.ID = dbo.InvtrySelections.ID
> WHERE (dbo.InvtrySelections.MachName = HOST_NAME())
>
|||One possible cause for seeing things like #deleted is a missing primary key
or Access is not able to determine which field is the primary key.
You have said in your first post that you have defined a composite primary
key on two field. This is quite possibly the source of your problem: you
should try replacing it with a single field primary key. From past
experience, Access seems to have a lot of trouble with linked tables or
views having composite primary keys.
Also, take a look at the following article; in case it might help you:
http://support.microsoft.com/kb/q209123/
Sylvain Lafontaine, ing.
MVP - Technologies Virtual-PC
E-mail: http://cerbermail.com/?QugbLEWINF
"Neil" <nospam@.nospam.net> wrote in message
news:hFf9f.3901$yX2.1657@.newsread2.news.pas.earthl ink.net...
> "Sylvain Lafontaine" <sylvain aei ca (fill the blanks, no spam please)>
> wrote in message news:uQV0$Ra3FHA.2432@.TK2MSFTNGP10.phx.gbl...
> I wasn't aware that I had done that.
>
> Good point. I created a view that returned the value of HOST_NAME(), and
> it linked fine into the MDB. I also created a new table, gave it a
> two-field PK, and used HOST_NAME() as a parameter for one of the fields in
> a view. That view also linked and displayed records fine. (Didn't do a
> two-table test, which would be similar to what I'm working with. But it
> shows that HOST_NAME() works fine with MDB linked views.)
> Neil
>
>
|||Also, if possible, that a look on the SQL-Server with the Profiler or
activate the ODBC tracing option. This will give you the possibility of
seeing what Access is trying to do.
Sylvain Lafontaine, ing.
MVP - Technologies Virtual-PC
E-mail: http://cerbermail.com/?QugbLEWINF
"Sylvain Lafontaine" <sylvain aei ca (fill the blanks, no spam please)>
wrote in message news:uTA0rGd3FHA.2640@.TK2MSFTNGP09.phx.gbl...
> One possible cause for seeing things like #deleted is a missing primary
> key or Access is not able to determine which field is the primary key.
> You have said in your first post that you have defined a composite primary
> key on two field. This is quite possibly the source of your problem: you
> should try replacing it with a single field primary key. From past
> experience, Access seems to have a lot of trouble with linked tables or
> views having composite primary keys.
> Also, take a look at the following article; in case it might help you:
> http://support.microsoft.com/kb/q209123/
> --
> Sylvain Lafontaine, ing.
> MVP - Technologies Virtual-PC
> E-mail: http://cerbermail.com/?QugbLEWINF
>
> "Neil" <nospam@.nospam.net> wrote in message
> news:hFf9f.3901$yX2.1657@.newsread2.news.pas.earthl ink.net...
>
|||Re. the composite primary key, note that in my test I did create a table
with a composite primary key, to simulate the situation, and it worked fine.
I followed up on that in my more recent post in this thread, which shows
that the situation is now even more bizarre.
Regarding changing to a single field primary key, I do not believe that is
possible. The main table has a single-field primary key (int, identity), and
the other table (which has a one-to-one relationship with the main table)
has a dual primary key -- one field corresponding to the main table's
primary key, and the other containing the machine name. That table has to
have both fields in the primary key.
The resulting view can have a one-field or two-field virtual primary key
when linked in access, depending on whether or not I include the machine
name field in the resultset. Seems to me that it's better to include it and
have a two-field primary key, so that Access can determine the record.
Neil
"Sylvain Lafontaine" <sylvain aei ca (fill the blanks, no spam please)>
wrote in message news:uTA0rGd3FHA.2640@.TK2MSFTNGP09.phx.gbl...
> One possible cause for seeing things like #deleted is a missing primary
> key or Access is not able to determine which field is the primary key.
> You have said in your first post that you have defined a composite primary
> key on two field. This is quite possibly the source of your problem: you
> should try replacing it with a single field primary key. From past
> experience, Access seems to have a lot of trouble with linked tables or
> views having composite primary keys.
> Also, take a look at the following article; in case it might help you:
> http://support.microsoft.com/kb/q209123/
> --
> Sylvain Lafontaine, ing.
> MVP - Technologies Virtual-PC
> E-mail: http://cerbermail.com/?QugbLEWINF
>
> "Neil" <nospam@.nospam.net> wrote in message
> news:hFf9f.3901$yX2.1657@.newsread2.news.pas.earthl ink.net...
>