Migration from Oracle to Teradata- Basic Analysis

On Request of one of the viewers, I have detailed here some information to have in mind while migrating from oracle to teradata. FIrst of all the following analysis is not biased and I am not proving either Teradata or Oracle is better. Both hav different features and both are good in their areas. The following anslysis is purely related to the senders query.


Senders Query read as follows-
Hi Krish,
I would need some suggestions about the Impact on moving data sources from Oracle to Teradata.We have 4 packages that are impacted in that area and each having about 150 Report Studio reports.  They said, that they are doing fork lift and the data items will also not change. Was wondering if you can help me doing the impact analysis and this is my first time in a project like this.

Thanks

Sravanthi

Now, Lets discuss if it is worth migrating from Oracle to Terradata.

My answer is one word YES. If your client is concentrating on huge data managemnet then terradata is the one but a bit expensive. This is not a technical issue and i have no comments on that. TerraData is really catching up now a days and argubly having the better architecture and a slight edge over ORACLE. Teradata has a cutting edge multi processing RDMS system which oracle doesnt have until the invention of Grid Computing.

Oracle on the other hand is mostly an OLAP architecure and if the client is ready for taking up the OLAP systems, then Oracle is quiet good and to say it is the best. It is cheaper compared to teradata as well.

But, this is all till the both giants join hands to provide a combined result to the client. Oracle now gains using the teradatas data handling ability. Oracle vs Teradata is the age old saga now.

Now, coming to the senders query, Yes the fork lifting from oracle to teradata is possible and can be done easily if the architectures are well aware of the data models of the existing data.

• Oracle attributes and Teradata attributes for the tables differ and the intermediate, temporary, lookup tables are to be properly mapped for the use in teradata.
• What if the lookup, temporary and intermediate tables are over looked ? The teradata will not get the right data and the business users might not get the sufficient data. 

• If we dump from oracle to teradata straight away meaning fork lift, the keys in teradata might not work well because there is a huge difference in handling keys between both of these sources and if overlooked, there will be overly dumped teradata and with worst performance.

• There will be some minute information that have to be taken care while moving like the field types. For example In Oracle there is a data type named datetime and where as teradata reads them as date and time.

In this context, the 4 packages that are dependencies of your reports willl not change but the way data is populated in the data items might get changed if they overlook it as per my explanation above. It purely depends upon how the architects have designed the functional spec of the entire project. The other factors that are to be considered are the versions of oracle and teradata since oracle has underwent lot of variations and also the teradata and supports many features now globally.

You didn't mention the reporting tool here. Considering it as cognos, the data items have no change but the data in case of datetime (date and time seperately in teradata) and the keys and the indexes like bit map index which is not in the scope of teradata.

Hope, this will help you for initial understanding and constructing your ideas from there.

~Urs Krish