Another 6 Oracle goodies

Written on 25 July 2011, 12:16pm

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Continuing the Oracle Cheat Sheet 🙂

1. Create an Oracle user


create user xxx identified by yyy;
grant connect, resource, unlimited tablespace to xxx [identified by yyy];
grant create session to xxx;

2. Extend tablespace


ALTER DATABASE
DATAFILE  'C:\ORACLEXE\ORADATA\XE\SYSTEM.DBF'
RESIZE 1000M;

link

3. Invoking UNIX commands from SQL*Plus

You can invoke a UNIX command from SQL*Plus by using “HOST COMMAND”:

host ls -la *.sql 

lists all SQL files in the current directory
(more…)

A little bit about Fusion Tables

Written on 22 May 2011, 10:49pm

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Google Fusion Tables is a modern data management and publishing web application that makes it easy to host, manage, collaborate on, visualize, and publish data tables online.

So as far as an user is concerned, a Fusion Table is a virtual table stored in the cloud, on which he can perform the regular CRUD operations. Here comes the nice part: the language on which you can perform these operations is SQL-like. The API is designed so that you can use URLs like
http://www.google.com/fusiontables/api/query?sql=select+*+from+1234567
The output of this request is a CSV text, with the contents of the selected table.

Let’s assume that you have a Fusion table where you store some physical addresses for some items. Below is a very simple PHP script which reads the contents of the fusion table, parses it, extracts the address, then performs a geocoding request using the geocoding API, parses the JSON object and outputs the latitude and longitude of the given address.

<?php
//run sql query to get data from fusion table
$url = 'http://www.google.com/fusiontables/api/query?sql=select+*+from+822057';
$lines = file($url);

$i = 0;
foreach ($lines as $line_num => $line) 
{
	//parse csv line
	$csv = str_getcsv($line);

	//extract the address
	$address	= $csv[7];
	
	if($address)
	{
		//we need to geocode the address to get the latitude and longitude
		$url_address = urlencode ($address);
		$geocode_url = "http://maps.google.com/maps/api/geocode/json?address=$url_address&sensor=false";
		$geocode = file_get_contents($geocode_url);
		$output = json_decode($geocode);

		$latitude = $output->results[0]->geometry->location->lat;
		$longitude = $output->results[0]->geometry->location->lng;

		//sleep for a second
		sleep(1);

		//do something nice with all this data

	}
}

?>

6 useful Oracle commands

Written on 26 March 2011, 12:43pm

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This is more of a reference post to store some useful Oracle features. Or a cheat sheet if you wish 🙂

1. How to find the maximum column size in a table


select
       max(vsize(mycol))
from
       mytable;

2. How to paginate in Oracle using rownum

Method 1:


select * from 
( 
       select rownum r, a.* from 
       (
             YOUR_QUERY
       ) a 
       where rownum < = 10
) 
where r >= 1;

Method 2: (more…)