Sometimes you need to remove nasty duplicate on a table, based on a subset of the column. On every big database there is something called “rowid” which can be used to indentify a column in a unique way. On PostgreSQL is called ctid, as we shall see:

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Oracle SQL Developer is full of nice feature, damned by a overwhelming options pane, like the one I will describe to you right now.

Even if  Oracle databases (<12) does not support auto increment, you can easily ask to your sql data modeler to generate for you a sequence and a trigger in a automatic way.

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Oracle SQL Developer is full of nice feature, damned by a overwhelming options pane, like the one I will describe to you right now.

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Disapprove with me!

Okey, you know Oracle. A very good database, a very old database, a very solid rock. Not famous for its error messages. I have already stumbled upon a misleading error on the old rock.

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Working in a big company, my work laptop came with MS-Windows7 Enterprise installed. But as you imagine, Unix is my preferred desktop environment. So let’s how to configure a perfect Debian Linux for a old wolf consultant like me. You will be able to install commercial software mubmo jumbo like Oracle Express and IBM Websphere in a snap, and have a 64 rock solid system, easy to bring in a USB stick if you like.

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I stumbled upon a very brain-f**k error on Oracle 10g on these days.

Context: the following query [sql]SELECT * FROM (
SELECT TO_NUMBER(CUSTOMER_ID) AS SNDG FROM BAD_CODES_TABLE WHERE
AND I_LIKE=UPPER(‘STATIC_CONDITION’) AND CUSTOMER_ID NOT LIKE ‘%P%’ ) S WHERE TO_NUMBER(S.SNDG) >2000[/sql] could trigger a Invalid number if CUSTOMER_ID column contains invalid numbers.

Why?

Well…if you ask to “explain plan”, you will get something like

• a table full scan
  • Filter Predicates AND
    • I_LIKE=UPPER('STATIC_CONDITION')
    • TO_NUMBER(S.SNDG) >2000
    • CUSTOMER_ID NOT LIKE '%P%'

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