Oracle Migration Workbench - Part 5 - Page 2

December 22, 2004

Picking up where we left off in Part Four

After starting OMWB, select Action>Capture Source Database and the Capture Wizard starts. The following series of screen shots is similar to what we already saw with the MySQL example, so they are shown without comment.

After clicking "Yes" at this last window, let's generate a migration report and view its contents. You generate the reports via the Report menu and OMWB informs you as to where they are located.

Clicking OK results in the report being presented to you in your browser. Let's look at the details for Northwind's stored procedures. The first line item has to do with a "set ROWCOUNT" statement in the Ten_Most_Expensive_Products procedure. Oracle does not support "set ROWCOUNT" which is what SQL Server uses to return (in this case) the top ten, umm, most expensive products.

The main body of the original code is:

ALTER  procedure "Ten Most Expensive Products" AS
SET ROWCOUNT 10
SELECT Products.ProductName AS TenMostExpensiveProducts, Products.UnitPrice
FROM Products
ORDER BY Products.UnitPrice DESC

To perform the manual conversion, you have at least two options.

Option 1) Modify the original code in SQL Server (or Oracle) to something you can immediately use in Oracle. You can simply run the SELECT part of the code and see that any product with a price greater than 44 is going to be in the top ten. Of course, you will be performing regular and frequent checks to ensure "44" is the correct value to distinguish the top ten most expensive products from the rest.

The kludged code is shown below.

ALTER procedure "Ten Most Expensive Products" AS
SELECT Products.ProductName AS TenMostExpensiveProducts, Products.UnitPrice
FROM Products
WHERE UnitPrice > 44
ORDER BY Products.UnitPrice DESC

Option 2) Modify the original code in SQL Server (or Oracle) to use ANSI SQL standards or syntax. This may or may not be simple, depending on your knowledge of what ANSI SQL looks like when compared to SQL Server or Oracle SQL. If you do not know how to reformat "set ROWCOUNT" to ANSI SQL (or a comparable construct in Oracle), but need to get this migration project done like yesterday, do what you do know and go back and fix it later.