Recipe 14.8 Reference Data from More than One SQL Server Database in an ADP

14.8.1 Problem

You'd like to have your ADP connect to multiple SQL Server databases at one time. However, the Data Link dialog allows room for only one SQL Server database.

14.8.2 Solution

Although at first glance this seems to be a problem, the solution is readily at hand with SQL Server's three-part naming convention. You are probably already familiar with the OwnerName.ObjectName syntax for referring to SQL Server objects, which is needed when users other than the owner (or creator) of that object wish to use the object. The three-part naming syntax is:

DatabaseName.OwnerName.ObjectName

To refer to another SQL Server database in your ADP, follow these steps:

Create a new project and link it to the Northwind database. You can look at the list of tables and see only the tables from Northwind.
Create a new form. Type the following statement into the RecordSource property of the form:
```
SELECT * FROM pubs.dbo.authors
```
You will then see the Field List for the authors table in the pubs database. Figure 14-18 displays the Field List from the sample form, frmPubsAuthorsSQL, and shows that the form is now bound to data in the pubs database, not the Northwind database.

Figure 14-18. The Field List from frmPubsAuthorsSQL

Alternately, you can create a view in the Northwind database that selects data from the pubs.authors table:
```
CREATE VIEW vwPubsAuthors
AS
SELECT au_id, au_lname, au_fname, phone, 
  address, city, state, zip, contract 
FROM pubs.dbo.authors
```
You can then base forms and reports in your Northwind project on the view.

14.8.3 Discussion

SQL Server allows users to access other databases residing on the same server when the three-part naming syntax is used. However, users must have been granted permissions in the source database if data is to be accessed with a direct SQL statement. SQL Server will return a permissions error message if those permissions have not been granted.

Working with data from multiple databases is easy in ADPs, even though you see the objects from only one database listed in the database window. Just remember to use the three-part naming syntax.

If the data you need is not just in another database but on another server, it gets a little more complicated. In this case, you need to set up a linked server in SQL Server to access the data. Linked servers in SQL Server use OLE DB providers, which means you are not limited to only SQL Server data. Linked servers allow you to use SQL Server as a gateway to many different data sources, just as you may use Access databases to link to multiple data sources.

[ Team LiB ]