?

Log in

No account? Create an account
current entries friends' entries archives about me Previous Previous Next Next
Technical Life - cellophane — LiveJournal
the story of an invisible girl
renniekins
renniekins
Technical Life
read 16 comments | talk to me!
Comments
pstscrpt From: pstscrpt Date: April 2nd, 2008 01:18 pm (UTC) (Link)
stored procedures wherever possible
75% of my work since June has been PL/SQL programming, so I've got that part covered. Would the hard parse be where it does the hash comparison to see if it already has that SQL compiled?

it's not true in Oracle that NULL = NULL
SQL Server is descended from Sybase, but they corrected the "Null = Null" thing in SQL Server 7 (the version before 2000), and it returns Null, like it's supposed to. I was just getting started in databases then, and was surprised to learn that, because I didn't know you could successfully compare Null to Null. Anyway, I'm kinda surprised Sybase hasn't changed that, yet.

People have been complaining about Oracle treating empty strings as Null for many years. I hear rumors they're going to fix it, but nothing concrete.


But there's subtle things that make it stupid.
Yup. One thing I've learned is that, even though a WHERE EXISTS may seem like it's saying exactly what I want and ought to be more efficient, it's likely to have 300 times the execution cost of a derived table equivalent. I'm not really sure, though, if the optimizer really does just have more shortcomings, or it's that I had eight years of experience learning what SQL Server likes.


Sybase and Oracle like to miss an index and convert the indexed columns to your literal's type rather than convert your literal to the type supported by the index.
SQL Server does that, too. You can have a VarChar column and do a select "Where MyColumn = 3", and it will work until somebody puts in a value that can't be interpreted as a number.


And a premium was placed on using Company Standard Products
That's how we wound up using Oracle's Java tools at Talk America (after they bought out LDMI, where I used to work). The idea was that we could just call up Oracle for help, no matter where in the stack a problem occurred. I think that ended when Talk America was bought by Cavelier, though.
read 16 comments | talk to me!