Re: Need help to understand difference, and contrast between Relational database model and the Object-Oriented model

From: Nobody <nobody_at_nowhere.net>
Date: Wed, 31 Dec 2003 13:07:24 GMT
Message-ID: <gSzIb.703884$Tr4.1770994_at_attbi_s03>


You are missing the point. When I said "some sort of physical pointer" I didn't mean direct file offset: I glossed over this because different systems implement it differently. You can't apply your one experience to a whole class of databases; there is no rule saying a database must exist in one file.

The point of my posting was the static versus dynamic relationships between objects.

Craig Tait wrote:
> I dont beleive this is correct as my experience with R83 pick 15 years ago
> accesses data using linked chains with a direct reference to Physical
> storage location on disk. Anyone who ever had a GFE (Lost chain) will know
> this. I have on a few occasions had to go through the physical chains and
> repair them. This is primarly why Pick was always so fast using pre
> allocated chunks of space on physical disk in a contiguous blocks so related
> data is referenced in a continues read primarly on the same sector on Hard
> disk. This is why housekeeping file sizing was so important so as not to
> have any data fill beyond its allocated file size and flow into overflow
> space (kind of a pre allocated area for file fragements on disk).
>
> So I think that this (I might be wrong) proves
>
>
> "Nobody" <nobody_at_nowhere.net> wrote in message
> news:xzbBb.65050$_M.317461_at_attbi_s54...
>

>>Relational databases use keys.  Object databases use some sort of
>>pointer to physical storage location.
>>
>>That's all.
>>
>>
>>yensao wrote:
>>
>>>Hi,
>>>I have a hard time to understand difference and similarities between
>>>Relational database model and the Object-Oriented model. Can somebody
>>>help me with this?
>>>
>>>
>>>Thank you in advance.
>>>
>>>Yensao
>>

>
>
Received on Wed Dec 31 2003 - 14:07:24 CET

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