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Null Value [message #30343]

Mon, 26 April 2004 02:38

Ajendra
Messages: 165
Registered: February 2004

Senior Member

What is the memory size of a NULL value. I mean how many bytes does a NULL value aquires ?

Thanks & Reagrds

Ajendra

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Re: Null Value [message #30344 is a reply to message #30343]

Mon, 26 April 2004 04:12

lalitha
Messages: 39
Registered: June 2002

Member

Hi
Null is not at all a value. It's simply void. Normally
in the remaining languages whenever we don't use
the allocated space(ie for a variable), the previous memory contents will be placed as it is. And whenever we store value the new contents overwrites the pervious
garbage values. But in oracle once after memory allocation (ie variable or instance creation) there will not be any garbage values. That is memory space doesn't contain any value. This status will be considered as null . That's it.
Again we are making comparisions with nulls means simply we are checking for that no value status itself.
lalitha

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Re: Null Value [message #30354 is a reply to message #30344]

Mon, 26 April 2004 21:06

Ajendra
Messages: 165
Registered: February 2004

Senior Member

Lalitha Thank you so much for your briefings. I am getting new ideas. Still I do have doubt. Could you please clarify me again.

As per you "But in oracle once after memory allocation (ie variable or instance creation) there will not be any garbage values. That is memory space doesn't contain any value. This status will be considered as null . "

"That is memory space doesn't contain any value" if yhis is the case, that memory space must occupy some Bytes ? How many bytes could be that.

For Example X:= 12; -- It stored an integer value and occupies certian Bytes
Then X:= NULL; -- There should be certian bytes stored on that space?

Thanks
Ajendra

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Re: Null Value DOES occupy memory [message #30358 is a reply to message #30354]

Mon, 26 April 2004 22:24

Sashi
Messages: 22
Registered: January 2004

Junior Member

NULL value DOES occupy memory in ORACLE.
It differs as where the column exists in ORACLE.
If the column having NULL is the last column then it occupies less memory than the cols present between any two columns

Last Column NULL Values occupy: NO Memory
Other Column NULL values occupy: SINGLE BYTE

Rgds
Sashi.

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Re: Null Value DOES occupy memory [message #30369 is a reply to message #30358]

Tue, 27 April 2004 03:37

Pulkit Agrawal
Messages: 5
Registered: April 2004

Junior Member

HI Sashi,

Thanks for putting light on Null value memory size.
Can we calculate its size by any means. I tried with Length function but it doesn't return any thing.

Regards
Pulkit Agrawal

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Re: Null Value DOES occupy memory [message #30378 is a reply to message #30358]

Tue, 27 April 2004 20:38

Ajendra
Messages: 165
Registered: February 2004

Senior Member

Thats g8 stuff Pullkit. Thanks. Is there any way to verify that NULL values occupies single byte.

Anyone knows the link in Oracle Manual for it.

Regards
Ajendra

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