If you’ve got a deal with Teradata as your POA system and are looking to migrate data from existing system; then this post is for you. Though I started working on this task(understated :)) some 6 months back, I decided to post once I ended that journey.
So what do I mean by “Data Migration”. It means copying your data from source folder and pasting it in target folder. Simple yet complex as things will unfold and one would wish it was as simple as cut-copy-paste. All hopes down, it isn’t.
Data Migration is like moving from one house to another. True story. You’ve got to analyze a huge deal. And I will try to put it in a simple steps:
- What you have in present house?
- Do you need it in your new house?
- Where will you place it?
- Most importantly, how are you going to port it?
One may feel that #4 is the crux but believe me every one of it is critical and if you under estimate it; it will come back and make sure you over estimate the next time 🙂
Also, since the entire process is comprised 3-4 tasks, each being substantial, I will posting a series here. First one contains the concept, overview & design. All the posts will not have a detailed code base associated with it. The idea is to share the approach with some code snippets. I do not intent to make it specific to particular source databases and putting a lot of code.
So coming to the technical part; I worked on migrating data from Sybase(ASE & IQ) to Teradata. I began with analyzing what I had within the Sybase environment that had to be posted to Teradata. Next, I had to study the demographics of objects that had to be migrated. Demographics would include the following :
- No. Of tables.
- Usage : Transactional or Analytical.
- Categorization based on size.
- Categorization based on data types. Columns with date/timestamps, encryption, etc. need special attention.
- Categorization based on BLOB/CLOB data(if present).
Answers to above questions will give you a fair idea of your current position. Remember, there will be a plethora of ideas striking your mind while working on this project. Always, stick to the basics in case of any confusion.
I will leave this post here. Next one in this series will cover the “Extract Creation” i.e. selecting data from various objects that need to be migrated.