Author Archives: Michael Simons

Optimizing the Oracle Query Optimizer

20-Oct-10

The Oracle Query Optimizer does a great job in rewriting Queries. For example the nested subquery in SELECT C.cust_last_name, C.country_id FROM customers C WHERE EXISTS (SELECT 1 FROM sales S WHERE S.quantity_sold > 1000 AND S.cust_id = C.cust_id);SELECT C.cust_last_name, C.country_id FROM customers C WHERE EXISTS (SELECT 1 FROM sales S WHERE S.quantity_sold > 1000 and […]

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Unicode substrings in Ruby 1.8.x

15-Oct-10

Here is how to get correct unicode substrings in Ruby 1.8.x require ‘jcode’ $KCODE = ‘u’   "öäüÖÄÜß".split(//)[4,2].join # ÄÜrequire ‘jcode’ $KCODE = ‘u’ "öäüÖÄÜß".split(//)[4,2].join # ÄÜ Don’t know, if this performes well… In case you have better ideas, please drop me a comment.

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Create reusable MySQL schema dumps

16-Sep-10

In case you need a MySQL schema transferred from one host to another and the schema names differ, you can ran into problems with a standard MySQL dump. Use the following statement to create a schema dump that contains all table and view definitions as well as all stored procedures without a reference to the […]

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iTunes terminal tipps 2010

13-Sep-10

4 years ago i had a first iTunes terminal tipp, here is a round up (all terminal tipps require Mac OS X): Invert the iTunes Store links in the list The littler arrows can either point to the iTunes store or to the same artist or album in your library. Invert their behavior to let […]

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Oracle “sleep” procedure: DBMS_LOCK.SLEEP

07-Sep-10

There’s a nice little “sleep” procedure in Oracle: A procedure that stops the execution of the current thread for n seconds. Strangely, this method can be called in SQL*Plus like so: EXEC dbms_lock.sleep(10);exec dbms_lock.sleep(10); but not in another stored procedure or function like so CREATE OR REPLACE PROCEDURE FOOBAR AS BEGIN DBMS_LOCK.SLEEP(1); END; /CREATE OR […]

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