Example How to represent table from RDBMS to HBase

1
votes

I read few articles and videos on YouTube about HBase. I understood that HBase is hadoop database. And it has different architecture (like column group etc.) compared to RDBMs. But I am still not clear how a RDBMs table will be represented in HBase?

Let me know if there is any suitable tutorial available.

e.g. If I have employee table with column as id, first_name, last_name, departement_id and salary. And Department table with departement_id, dept_name as columns.

If I want to represent it in HBase how will it be defined ? Can someone please elaborate.

3
hadoophbasenosql

3 Answers

1
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Please see the link. The internal architecture is different from the RDBMS. You have rows, column families, column qualifiers. Internally all the details are stored as key:value pairs. More videos with good information link. The question asked seems like you might be thinking to join those two tables. This post might give info regarding that aspect. There is also a Tall vs wide table design aspect here

HBase: The Definitive Guide book's chapter 9 talks about Tall-Narrow vs Flat-wide tables. (http://ofps.oreilly.com/titles/9781449396107/advanced.html)

which might help you in your decision. In a nut shell, your design would be based on which parameters you would like to retrieve data. Happy coding

1
votes

Basic concepts like "table in HBase can be visualized as Map of Map" and how timestamp is used was clarified by http://jimbojw.com/wiki/index.php?title=Understanding_Hbase_and_BigTable

Then I found explanation in this PDF very useful http://0b4af6cdc2f0c5998459-c0245c5c937c5dedcca3f1764ecc9b2f.r43.cf2.rackcdn.com/9353-login1210_khurana.pdf

1
votes

you can use sqoop to import and export tables from hbase to RDBMS and vice versa