Monday, March 31, 2008


HI All,
Here i try to analyze different Data loading methods available...and some other debatable issues..
Best Practices:
1.Always have the rightly balanced teams.
A typical ratio for medium complexity process would be(1:1:2 )(Functional:Technical Designer:Developers).
Techical designer should be a guy who understands both the importance of business and technical limitations.
And the rule should be , technical designer should always be involved at the Functional Discussions with the customer.
This always help for not committing things which are not technically feasible..(Nothing is impossible ..but the effort needed to make it happen is worth or not??)

2.The other big Question is how should I divide my project team???
Method A>Functional,Technical( With in technical people by technologies they are good at like ..reports ,Forms & OAF ...)
Method B> One Process one team.(Atleast team size should be more than 20 to implement this)

There are advantages & disadvantages of both the ways..I am part of implementations which are done both ways....Lets me list some of them...
Method A:
Advantages: Less time is taken for development of components..(As technical people are doing what they are good at..)
1.I don't know whether I am correct or not in quoting this but the truth is you will find a clear divide between the two teams..And once things start going wrong people start blaming each other...I think every one might have experienced it already..
2.For technical people it is even bigger loss because you work on different components belonging to different process and never understand how your component fits in the overall solution. At the end of day it will be just a
piece of code...
3.Any change in the process during the course of development is very difficult to handle, as there will be inter dependencies among components

Method B:
1.Every one will feel the ownership of the process and better team spirit.
2.Technical team will also have better understanding of the processes and will able to implement the changes faster (as In a development project change is unavoidable ) as they have all the components with them

1.Development time might be a bit long as the technical people in u r team might not have expertise in all the technologies involved in the process

My views might be a bit biased as I am strong supporter for method B..

Coming to our today's technical discussion loading..This will be one of the first steps(development) and the last step(before live) of a implementation..
The typical way of data loading is a three step process.
1.To load data from the legacy/Flat files to temporary tables.
2..Perform all the validations on the temporary table data and load it to the open interfaces or API's
3.Run the Open interface Concurrent programs/API's to load data to the standard tables.

First let me figure ways of data movement in oracle apps..
1.Open Interfaces-- used for live interfaces(every day activity) & one time loading
2.API's--Almost same as Open interfaces but are easy to handle.(validation & integrity logic is taken care by them)
3.Out Bound Interfaces--Required if we integrate oracle apps with third party or legacy systems
4.EDI--automation process..we will talk about them later

For loading data
SQL Loader:
1.Used when data is available in flat files(tab delimited,Comma delimited)
2.Faster & Easier way of loading data
3.Can use sql functions to modify data

DB Links: if the legacy systems is on oracle data base the best thing is to get access to the data customer want to import through db links

Data loader tool : These are third party tools used for loading ,which automates the process of punching data.There are very much user friendly and not much technical expertise is required to work with them.
But the biggest disadvantage of these tools is they are slow.If you have huge data it is not advisable to use them(unless u r patient enough to see thru :-) )
The data loaded will be valid because it is as good as manual punching..

XML: Oracle Provides Apis to import XML data and to export data into XML.This should be most convenient way for data interaction as most of the other technology systems are able to parse XML data easily.
There are some limitations(can be easily overcome) also for these in oracle like while importing XML data into oracle tables oracle can't parse huge files

WEBADI: These are oracle provided templates for data loading into some standard interfaces.Easy to use. we can create the custom api's and use for data loading..i felt this is one of the best ways of loading data

UTL_FILE: it is PL/SQL way of loading data into oracle tables.This packages gives us the API to read and data into flat files.This method is very useful when the data to be loaded is less and more validations are required
before loading.One of the limitations of this pacakge it reads data in lines and the maximum length it can read is 1022 charecters..In writing data to files it can write only 32K in one shot..later we need to close the file
and reopen it again..

External Table:This concept concept comes from Oracle 9i onwards.This is one of the easiest way of loading data.Once you create the external table you can simple use the select stament to query the table.
On performance basis this is as good as Direct path loading of SQLLDR.(Technical People Give a try for this...)

Caution:Disable any indexes on the table before loading data..other wise it will slow down the process of loading data.

On summary for all conversions(one time data movement) use External Tables or SQL Loader
For interfaces use PL/sql,dblinks or XML
HI all i have not used SQL loader much..most of the time i have used External tables ,UTL_FIle and XML.So people who has much exposure can come up with any limitations or advantages of it..
Plz let me know if any thing is wrong or any other suggestions to make this better....


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Sridevi Koduru said...

Sridevi Koduru (Senior Oracle Apps Trainer
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