It’s a follow-up to the previous post.
As it turned out, implicit date conversions may also prevent Oracle from doing the partition pruning. For example, if you have a table INVOICES with a range partition on INVOICE_DATE field, then expression
SELECT ... WHERE invoice_date >= '01-MAR-09' AND invoice_date < '02-MAR-09' will not perform the partition pruning, whereas
SELECT ... WHERE invoice_date >= TO_DATE('01/03/2009', 'DD/MM/YYYY') AND invoice_date < TO_DATE('02/03/2009', 'DD/MM/YYYY') will.
Read more →When I was going through PL/SQL procedures written by some of my colleagues, I noticed a few mistakes made around the Oracle’s date conversion functions. There are some peculiarities about those functions that I thought everyone knew about. But I reckon if I write about it, it may help others to avoid such mistakes. I also allowed myself to outline a few rules that, if you adhere to them, will help you to write better programmes.
Read more →Virtually every software development methodology stresses a need for specifying how the software end product is expected to work before starting the programming. But the truth is that writing specifications is boring. And most programmers, being lazy people (in good meaning of “lazy”. Yes, I believe there is a good meaning) try to avoid boring work. So, when the specs are written, they are often incomplete and don’t cover all the possible scenarios.
Read more →A few days ago I went to a presentation by an Oracle recruiter. He talked about the ways Oracle searches for the potential candidates and and hires them. One particular thing that struck me was that Australian Oracle recruitment team does not use specialised recruitment web sites.
About a decade ago, looking for a job was all about reading newspaper ads. Then along came job web sites, and the recruitment landscape changed forever.
Read more →Once during one of the projects I was asked what was the risk of something going wrong. I remember I answered that we, programmers, do not assess risks. We just do everything possible to prevent them. “There is no point”, I said, “to calculate the chances and the impact of a file not being in the incoming directory upon the start-up of the process if we can implement a simple check and avoid the disaster”.
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