DB2 Basics: Aliases

My blog entries covering the DB2 Basics continue to be my most popular blog entries. This is probably because they appeal to a wider audience – even non-DBAs are interested in them and I continue to rank highly in Google search results.… Read the rest

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Redesigning Tablespaces in an Existing Database

Like many applications, WebSphere Commerce puts all tables in USERSPACE1 unless they need larger page sizes. This actually works just fine for smaller and midrange implementations, but we have about one build a year that requires something else – either because of standards that client DBAs adhere to or because they actually are busy enough for I/O and separate buffer pools to matter.… Read the rest

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DB2 LUW – What is a Page?

The logical view of a database consists of the standard objects in any RDBMS – Tables, Indexes, etc. There are a number of layers of abstraction between this and the physical hardware level, both in the OS and within DB2.

Setting the Page Size

The smallest unit of I/O that DB2 can handle is a page.… Read the rest

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Oracle’s SCN Flaw – could it happen in DB2?

I read an article on a flaw in Oracle that was recently discovered. It had to do with the SCN number that is constantly increasing in any database:

http://www.infoworld.com/d/security/fundamental-oracle-flaw-revealed-184163-0

Thanks to my friend Fitz for bringing it to my attention – and you really should read all 6 pages of that article – it is fascinating for a database geek.… Read the rest

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Commerce Database Facts

So these are miscellaneous things that I sometimes note about Commerce databases. Though some of the details here may reference DB2, the basic facts are RDBMS-independent, so they would be true for Oracle Commerce databases as well as DB2 ones.

Most tables have generated primary keys

Commerce tends to use sequential numbers for most primary keys, or as a component of a composite primary key.… Read the rest

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