conversion from Informix to oracle

[jonax]

Hi everyone...

I have a 450GB database size in informix, if i migrate my database from informix to oracle9i database, what will be the size of the database in oracle9i after the conversion?

thanks,

[njia_1]

no likely you get the answer you want, why not try to do the conversion and let us know, I believe you will have to test the conversion procedure before implementing it on the real database.

thanks

[Indira Aramandla · Accepted solution]

Hi Jonax,

I guess the size of the target database will be close enough to the source database size.

The conceptual differences in the storage structures between INFORMIX and Oracle do not affect conversion process directly. However, the physical storage requirements need to be in place before the conversion begins.

You can control the physical placement of database objects in either database. In INFORMIX, you use the 'IN dbspace' clause. In Oracle, you use the TABLESPACE clause in CREATE TABLE statements.

An attempt should be made to preserve the storage information during the conversion. The decisions that were made when defining the storage of the database objects for INFORMIX should also apply for Oracle.

Initial object sizes and physical object placement are especially important.

DATATYPES

INFORMIX Oracle Equivalent
INTEGER, INT NUMBER(10)
DECIMAL(p,[s]) NUMBER(p,{s})
CHAR(n) VARCHAR2(n)
BYTE LONG RAW

The best approach is to create the database manually in Oracle. INFORMIX applications that use two or more databases on the same server usually translate to one Oracle database with several tablespaces.
In most cases, the INFORMIX application should be converted so that one server in INFORMIX is converted to one Oracle database instance.

INFORMIX does not support database links, sequences (uses SERIAL datatype instead), snapshots, and tablespaces (uses dbspaces instead)


Indira A

[Yogeeraj_1]

hi,

if you decide to use the COMPRESSION feature when creating you object, you might indeed turn up with a smaller sized database.

but, the truth is that you must Benchmark, Benchmark, Benchmark. Try it out -- see what it does for you.

You will need to test your migration on another marchine perferrable and see how it works!

It is also advisable for you to work closely with oracle support!

btw. why 9i and not 10g??

good luck!

kind regards
yogeeraj

[jonax]

Thank you very much for the info.