December 7, 2014

Dynamic HTTP endpoint in Oracle Service Bus 12c based on values in a database routing table

This article outlines how to set a dynamic endpoint in an OSB HTTP Business Service. The endpoint is retrieved from a routing table which resides in an Oracle 12c database.

Components used for this solution:

Ubuntu Linux 14.04 64bit
1. JDeveloper, running the Quick Start Oracle Fusion Middleware suite
  1. Oracle Service Bus 12c
  2. Oracle Weblogic 12c
  3. OSB Project location:
    1. https://github.com/visscher/Fusion/tree/master/DBRouting
2. Oracle Virtualbox Developer Days image for DB 12c, running:
  1. Oracle Database 12c
3. Oracle SQL Developer 4

This picture shows the running solution in the OSB test console:

Database table preparation

We need a routing table in our schema, I’m using this table setup:

CREATE TABLE "C##JORIS"."ROUTINGTABLE"
  (
    "ROUTE" VARCHAR2(50),
    "ENDPOINT" VARCHAR2(100)
  );

Where ROUTE stands for the identifier and ENDPOINT is the HTTP endpoint we try to reach.

I’ve inserted two rows:

Insert into ROUTINGTABLE (ROUTE,ENDPOINT) values ('SalesOrder','http://localhost:7101/salesEndpoint');
Insert into ROUTINGTABLE (ROUTE,ENDPOINT) values ('FinanceReceipt','http://localhost:7101/financeEndpoint');

These two endpoints will point to very simple OSB services which we will create in a moment.

Weblogic configuration: JDBC Data Source

We need to configure a JDBC data source in our Weblogic server, this data source is used by the XQuery function to execute SQL.

Start JDEVeloper, select your integrated Weblogic Server and start it up.

When your domain is started, open the WLS Console:

http://127.0.0.1:7101/console/

Navigation in Console: DefaultDomain - Services - Data Sources

Create a new datasource, in my example I use the JNDI name “LocalDB“

When you’re done with the configuration, test the datasource to make sure all is well:

The status message will be green and show a check mark if you’ve configured your data source correctly.

JDeveloper: Oracle Service Bus project

If you import the DBRouting project from here, you should have all the necessary services.

I will only discuss the assign steps which are needed in the DBRouting_v1Pipeline.pipeline.

There are three assign actions:

1.) Assign $route: node-name($body/*[1])
This assign determines our routing key. It is the same key as
the first column in the routing table.
The XPath here is used to select the name of the first node
but you can change this to what you want to route on.

2.) Assign $query: 
fn:concat("select ENDPOINT from ROUTINGTABLE where ROUTE = '", $route, "'")
This assign determines the query which will be executed in
the next step. We want to select the ENDPOINT which belongs
to the ROUTE which was assigned in step 1.

3.) Assign $query: 
(fn-bea:execute-sql(
 xs:string("LocalDB"),
 xs:string("ENDPOINT"),
 $query
 )/*:ENDPOINT)[1]
This assign actually executes the SQL query to our database,
which is the first argument.
The second argument names the re-occurring rows, in this
case "ENDPOINT".
The thirst argument is the query to execute.
The XPath after the execute-sql statement is to make sure
we only get one endpoint.

4.) After those assigns, we use place a task “Routing Options” in the HTTP Route node:

We only use the “URI” Routing Option:

$endpoint/text()

This ends the article, if you execute the pipeline you will see the endpoint has become dynamic, it is retreived from the routing table:

Oracle Service Bus Console 12c : Pipeline Testing - DBRouting_v1Pipeline - Google Chrome_019

August 19, 2014

Can not connect to Virtualbox Guest Oracle Database 12c Developer Day Database VM due to Oracle Linux firewall

It seems there’s a firewall present on the latest Developer Days Database image which I’ve just downloaded from Oracle.

Description:

I enjoy using these images because it is a complete reference install of Oracle Linux, Oracle Database and Oracle SQL Developer (among others). Besides that, it only takes 10 minutes to setup a base install from the image.
Usually I like to connect from my local SQL Developer instead of the one inside the VM.

Problem:

But with this setup I could not connect when I added the NAT Port Forwarding in Virtualbox, it timed out when trying to connect. I could connect from the SQL Developer inside the VM, just not through the NAT port which was forwarded (important: see the bottom of this post to check the NAT Port Forwarding settings in Virtualbox)

Solution:

It’s fairly easy to add a firewall rule which allows access to port 1521 on Oracle Linux, we can even do it with a GUI:
Select Menu “System” – “Administration” – “Firewall”
Then follow these steps:

Click [Other Ports]
Click [Add]
Select [User Defined]
Enter Port: “1521”
Select Protocol: “TCP”
Click [Apply]
Click [Reload]

You’ve just added port 1521 to the iptables which makes it okay to connect to this port from another IP outside the local machine.
We can test from SQL Developer, running on the Host:

And it works! 🙂

Extra: NAT Port Forwarding in Virtualbox

Just to be sure, these are the settings you’ll need to set inside the Virtualbox Manager to setup the port forwarding on port 1521 from the guest to the host:
Select the “Settings” of the Developer Day VM and then:

Select “Network”
Click [Port Forwarding]

Then in the Port Forwarding Rules:

Enter a descriptive name: “DB”
Enter the host port: “1521”
Enter the guest port: “1521”

August 12, 2014

Oracle SQL Developer 4 does not run on Oracle Java 7 on Ubuntu 14.04

Wow, ain’t this awkward :-). I cannot run Oracle SQL Developer 4 (4.0.2) on Ubuntu with Oracle JDK 7..

To be complete: when running SQL Developer with JDK 7 from Oracle itself, displays the following error;

joris@dipshit:~/programs/sqldeveloper$ ./sqldeveloper.sh
Oracle SQL Developer
 Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
LOAD TIME : 968#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x6aa69be0, pid=9537, tid=1836366656
#
# JRE version: Java(TM) SE Runtime Environment (7.0_65-b17) (build 1.7.0_65-b17)
# Java VM: Java HotSpot(TM) Server VM (24.65-b04 mixed mode linux-x86 )
# Problematic frame:
# C 0x6aa69be0
#
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /home/joris/programs/sqldeveloper/sqldeveloper/bin/hs_err_pid9537.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#
/home/joris/programs/sqldeveloper/sqldeveloper/bin/../../ide/bin/launcher.sh: line 1193: 9537 Aborted (core dumped) ${JAVA} "${APP_VM_OPTS[@]}" ${APP_ENV_VARS} -classpath ${APP_CLASSPATH} ${APP_MAIN_CLASS} "${APP_APP_OPTS[@]}"

Solution: Run Oracle SQL Developer with OpenJDK

First we’ll need to install OpenJDK:

sudo apt-get install openjdk-7-jdk

Then we’ll need to change the path which SQL Developer uses. This was asked once when you first started it and it is saved in the following path:

~/.sqldeveloper/4.0.0/product.conf

The file [[ product.conf ]] contains the value SetJavaHome, we need to change this to the OpenJDK path;

If you're running 32 bit Ubuntu:

SetJavaHome /usr/lib/jvm/java-7-openjdk-i386

Or if you're running 64 bit Ubuntu:

SetJavaHome /usr/lib/jvm/java-7-openjdk-amd64

After saving this change, you can start SQL Developer on Ubuntu 14.04 and it will use OpenJDK 7, without changing your regular Java settings!

December 6, 2013

Oracle SQL – BLOB to XML Type ( ORA-06502 PL/SQL : numeric or value error : raw variable length too long )

I am working with a database schema where xml content is being stored in a BLOB and I’m working on querying that XML.
When you cast the BLOB to VARCHAR, you’ll run into the limit of 2000 characters with the following error:

ORA-06502 PL/SQL : numeric or value error : raw variable length too long

So this trick came in handy:

SELECT XMLTYPE( BLOB_FIELD, 871 ) AS AWESOMEXML FROM YOUR_TABLE;

Please be very aware of the character set that you are using, you can enter a world of hurt when you’re using the wrong one. The number 871 is the character set UTF8, which we are using.
For other character sets, check http://www.mydul.net/charsets.html

May 17, 2013

How to try to drop a table without raising exception ORA-00942: table or view does not exist

With the piece of code below it’s quite easy to first make sure your table exists before dropping it, so you’re not running into SQL Error: ORA-00942: table or view does not exist
Script explanation: It will check if the table is present before trying to drop it.

-- Drop table
DECLARE
 l_count NUMBER;
BEGIN
 SELECT COUNT(1)
 INTO l_count
 FROM ALL_TABLES
 WHERE table_name = 'TABLE_NAME'
 AND owner = 'USERNAME';
 IF l_count > 0 THEN
 EXECUTE IMMEDIATE 'Drop table USERNAME.TABLE_NAME CASCADE CONSTRAINTS';
END IF;
END;
/

January 3, 2013

Oracle Database 11gR2, quick and easy

It’s been a while since the last article and I just found myself being enthousiastic about a neat Oracle hands on again. So while it’s downloading I might as well tell you guys about it.
Last year I have been working with Oracle XE a lot, but some features are not available in the express edition (XE), so some queries might not run as expected or simply don’t run at all. Oracle has a VM ware image, which provides a really nice solution for this problem:
They have created a database application environment inside a Virtualbox VM image, with the following specifications:

Oracle Linux 5
Oracle Database 11g Release 2 Enterprise Edition
Oracle TimesTen In-Memory Database Cache
Oracle XML DB
Oracle SQL Developer
Oracle SQL Developer Data Modeler
Oracle Application Express
Oracle JDeveloper
Hands-On-Labs (accessed via the Toolbar Menu in Firefox)

So if you’re looking for a nimble way to quickly run a OraDB on your laptop, without the hassle of installing all these components, this might just be what you’re looking for.
You can download the Oracle Developer Days 11g DB image here:
http://download.oracle.com/otn/other/virtualbox/dd/Oracle_Developer_Day.ova
The only prerequisite is that you have Oracle Virtualbox installed on your machine;
But this is easily installed via this link

In the coming days I will post another article, which will describe a neat way of connecting to this database!

The original article can be found here: http://www.oracle.com/technetwork/database/enterprise-edition/databaseappdev-vm-161299.html

June 25, 2012

Unlock HR user and schema in Oracle Database

In an Oracle database there is a sample user called “HR”. This user comes with a schema which contains data which is quite convenient for demo purposes.
You can unlock this user using the following steps:

Connect to your database with the system user
Execute the following command (Note: replace “password” with your password)
```
ALTER USER HR IDENTIFIED BY password ACCOUNT UNLOCK;
```
Log in to the database with the HR user and your specified password

You can use this user for tutorials / demo’s in almost all Oracle databases since the tables are all equal.

Screenshot - Tables, Views and Procedures for the HR user — Screenshot – Tables, Views and Procedures for the HR user

Ps. I’ve posted this small tutorial mainly because it will serve as a prerequisite for other tutorials.

Category: Database

Select an XML tag or node using Oracle PL SQL