Is it possible to recover an IMS DB Backup to Oracle

Question

I have an IMS DB Backup file which I have been asked to see if we can recover. Not having IMS, my goal is to somehow recover to Oracle 11g R2. Are there any resources where I can figure out if this is even possible, and what that process may be?

Answer 1

karluk wrote:
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the data will be encoded in ebcdic instead of ascii
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So what? Character conversion tables between EBCDIC and ASCII are readily availble. It's not exactly rocket science to include a conversion routine as part of the migration.True enough for character data. Not so true for 'binary' data, like cobol's COMP-3. So you gotta allow for some data being translated and some not. It is do-able as long as you know what is what.
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the application was probably written in cobol, and heavy use of the REDEFINES clause in data element definitions
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Again, so what? The quesion being asked is whether it's possible to convert IMS to Oracle. I answered, correctly, that it is. Any hypothetically necessary rewrites of the application code that uses the backend database is beyond the scope of this question.I never questioned if it was possible to convert IMS to Oracle (or any rdbms), per se. I did quite a bit of this in my cobol days, (converting from IMS to DB2 - and across ebcdic/ascii platforms) but had access working systems, and full record/table descriptions. Trying to reverse engineer it from nothing more than a backup is a whole different matter.
This one is not just a matter of rewrite of the app, it goes to the heart of how to interpret the data for conversion. Take this example of a record def in cobol
01  A-RECORD.
    05 A-RECORD-DATA  PIC X(50).
    05 REC-TYPE-A REDEFINES A-RECORD-DATA.
       10 SOME-STUFF      PIC X(10).
       10 A-DATE              PIC 9(6).
       10 SOME-DOLLARS  PIC S9(5)V99 COMP-3.
       10 OTHER-STUFF    PIC X(15).
    05 REC-TYPE-B REDEFINES A-RECORD-DATA.
       10 NUMBER1        PIC S9(7) COMP.
       10 NUMBER2        PIC S9(7) COMP.
       10 NUMBER3        PIC S9(7) COMP-3.
       10 NUMBER4        PIC S9(7) COMP-3.Does the first 10 bytes get translated from ebcidic to ascii? They do if they are SOME-STUFF, but not if they are NUMBER1, NUMBER2, etc. How do we know which it is? And what gets mapped to what in the relational database? Just what is the first 10 bytes of this record? No cheating now, for the OP's problem, you don't get to see the record description!
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Now throw in the complication that the OP apparently doesn't' even have a working IMS system, just a backup. So now you deal with whatever format that backup is in (the OP didn't say, probably because it never occurred to him that backups themselves could be in various file formats)
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An issue I also mentioned in my response. If he's lucky enough to have an unload rather than an image copy, the task becomes greatly simplified. An IMS unload would most likely be readily usable by SQL loader type utilities. An image copy, not so much.
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Again, expecting a working IMS system, where they have access to the DCLGENs to define the IMS data.
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Again, repeating an issue that I already addressed in my response.