MyISAM-Heap-ISAM-Merge

hello experts..
what are the differnces between MyISAM,Heap,ISAM and Merge when creating tables in Mysql db ?
yazan3000Asked:
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steve918Commented:
Hi yazan3000,

MyISAM - MySQL's implementation of ISAM, Does not support transactions or foreign keys, is extremely fast and excels in read-only enviornments,
             or read/write with a small/moderate number of users. For transactions/Large read/write capabilities check out InooDB
Merge - A merge table is actually a collection of tables, this allows you to have tables that exceed the maximum file size for your OS.
         This allows for extremely large tables over 2gb.  I think this only works with MyISAM tables.
HEAP - Tables are stored temporarily in memory, they do not survie  a reboot, but are very fast and efficient in read-only setups

check this out for more info
http://www.developer.com/db/article.php/2235521

Cheers!
0
SqueebeeCommented:
From an end user perspective, MyISAM is what you should be using unless you have reason to choose otherwise.

InnoDB is what you should use when you need row-level locking, foreign keys, and transactions.

HEAP is what you use when you need a very fast in-memory table, but a good buffer on MyISAM can have similar performance without losing the table in a power failure.

Merge is a way of grouping identical MyISAM tables into a super table.

ISAM is old, don't touch it.

So the moral of the story is: Use MyISAM until you need something more.


Regards,
Mike Hillyer
http://www.openwin.org/mike
0

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