Multiple Databases

[mzhu]

Hi Everyone,

I am new to Oracle. We are developing a web application. We used to use MS SQL Server to create a separate database for each customer user. Now we switch to Oracle. It seems that it is commen to have a single database with multiple schemas in Oracle. My question is -- What is the difference between single database and multiple databases in Oracle? Take our case as an example: We have 200 customers, so we can use a single database to create 200 schemas, OR we can create two databases and each database with 100 schemas. Which way is better?

Thanks.

[sreddy]

It depends on somany factors,to mention few

Application Requirement and Flexibility for system integration
Hardware Resources
Dependency between the customers data
Future enhancements and requirements
Data growth

Blah Blah...

Hope you got it. Keeping kinda things in mind justify it...

[hbk_emp]

Databases cannot be assumed on no of users connecting to it but it differs by data. suppose you have a huge application and about 100 users login to it at the same time and that is related to accounting ,it is advisable to create one accounting named database and not 100 databases and giving links.
In you specific case as you have described for you 1 databases is enough and you only need another database if you are going to have a new system (application of hr/finance etc...)

[sambavan]

If undestand your question correctly, then the opinion of sreddy would hold good. On the other hand, there are some more concepts, when you talk about, multiple database, I presume that you mean individual schemas. Under such scenario, the advantages are that the database engine, otherwiese the instance under which these schemas are going to reside, would be one that would provide resources to these schemas. As a result, if the programing had been well designed, there are a number of advantages where the schemas could share the same resource efficiently, rather than each schema user having his or her own set of background process and some getting used to the max and some not. There is another way to split this, i.e you can have two instances, each with 100 users. As a result you would be more efficient in the resource usage, but you have to be aware that each instance by default would home around 10-...
process, if you are going to use the Multi threaded operation.

For a better undestanding of these concepts, it would be good for you to undestand the oracle's physical and logical structures, before you start implemeting things.

If you have any question in more specific, let us know and we will try to be more clear :)

Sam