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Natalka Roshak's picture

Recursive WITH, part II: Hierarchical queries

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In my last post, I looked at using recursive WITH to implement simple recursive algorithms in SQL. One very common use of recursion is to traverse hierarchical data. I recently wrote a series of posts on hierarchical data, using Oracle’s CONNECT BY syntax and a fun example. In this post, I’ll be revisiting the same data using recursive WITH.

Natalka Roshak's picture

Recursion with recursive WITH

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I recently had the opportunity to talk with Tom Kyte (!), and in the course of our conversation, he really made me face up to the fact that the SQL syntax I use every day is frozen in time: I’m not making much use of the analytic functions and other syntax that Oracle has introduced since 8i.

Partitioning and Oracle Standard Edition

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I first came across partitioning with release 7, when it didn't exist. Like many DBAs, I simulated it by writing a lot of application code. You can still do this – and you may have to if you haven't bought Enterprise Edition plus the partitioning option. Here's another way to do it, with partitioned views.

Role Playing Dimension in data warehouse

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Dimensions are often recycled for multiple purposes within the same database. For instance, a “Date” dimension can be used for “Date of Sale”, as well as “Date of Delivery”, or “Date of Hire”. This is often referred to as a “role-playing dimension”.

Transporting tablespace from 32 to 64 bit using RMAN

Performing a 32 bit to 64 bit migration using the Transportable Database RMAN feature

This note describes the procedure used to perform a 32 bit to 64 bit conversion of an 11.2.0.3 database on the Linux platform.

The RMAN CONVERT DATABASE command is used to automate the movement of an entire database from one platform (the source platform) to another (the destination platform).

This is provided that the source and destination platforms are of the same endian format.

For example between Linux X86 32 bit and Linux X86 64 bit.

Note the following:

When is an index access path better than a full table scan?

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The cost based optimizer makes decisions that can be hard to understand. One of the hardest may be why it chooses indexed or scan access paths: a burning question for many DBAs.

Selenium Webdriver Online Training with Java Tutorial

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Selenium WebDriver is a website robot framework that allows you to implement your assessments against various windows, not just Opera.

Selenium WebDriver also allows you to make use of a coding language in developing your examination texts (difficult in Selenium IDE).

It's simple to employ conditional operations like if-then-else or change-event
You can also accomplish looping like do-while.
Following development languages are recognized by Selenium WebDriver:

What is DB Time? Where has it gone?

DB Time is the time spent by the database server executing user calls. What is this composed of? CPU time, waiting time, and IO time.

Windows Registry - ORACLE_SID

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Hi All,

I would like to share something about ORACLE_SID registry parameter.

I had a chance to restore (RMAN) a database on a new Windows server. The restoration/recovery was completed and there was no issue in logging to the database from the server.

The only thing I had to do was to set the ORACLE_SID variable everytime using the statement "set ORACLE_SID=abcd". I will encounter the error "ORA-12560: TNS:protocol adapter error".

Proxy authentication

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Proxy authentication has been around since release 9i, but it isn't widely used. It can be a very useful facility for giving certain users access to high privileges without having to give them any direct grants or roles, and avoids many of the problems of using shared accounts. It is of course fully audited.

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