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From:Jeremiah Gowdy Date:May 26 2005 4:26am
Subject:Re: InnoDB to MyISAM
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>> >>key relationships?
>> >
>> > MyISAM can't FK's.
>> Yes it can, they're just not enforced.
> LOL - that's just like saying that MyISAM supports transactions
> if you only do transactions that are a single statement...
> In other words: useles.

Somehow I use these "useles" foreign keys to create relational databases.

A foreign key is merely a column which references a primary key or a unique 
key in the same or another table.

I think you're confusing referential constraints with foreign keys.  Even in 
database systems that support referential constraints and cascade 
dependencies, the usage of such constraints on foreign keys is optional and 
dependant on your desire to trade-off referential integrity for performance.

In some systems, the performance penalty of enforcing referential 
constraints and doing deletions in dependant tables simply cannot be 
afforded during high usage hours for databases that serve real-time systems 
(I work in telecom for example), and therefore one may choose to implement a 
cleanup process during very low usage hours in the middle of the night to 
find orphaned records, delete them, and then optimize the table.  This 
allows you to avoid deleting anything but the primary record while people 
are waiting on the phone, which for MyISAM has the added benefit of allowing 
concurrent insert/select to continue in the dependent tables.

InnoDB to MyISAMScott Purcell25 May
  • Re: InnoDB to MyISAMDBA)25 May
  • Re: InnoDB to MyISAMRafal Kedziorski25 May
  • Re: InnoDB to MyISAMJeremiah Gowdy25 May
  • Re: InnoDB to MyISAMMartijn Tonies25 May
  • Re: InnoDB to MyISAMJeremiah Gowdy26 May
    • Re: InnoDB to MyISAMmfatene26 May
  • Re: InnoDB to MyISAMMartijn Tonies26 May
  • Re: InnoDB to MyISAMJeremiah Gowdy26 May
  • Re: InnoDB to MyISAMJeremiah Gowdy26 May
  • Re: InnoDB to MyISAMMartijn Tonies26 May
    • RE: InnoDB to MyISAMPeter Normann26 May
  • Re: InnoDB to MyISAMJeremiah Gowdy27 May
Re: InnoDB to MyISAMMartijn Tonies26 May
Re: InnoDB to MyISAMDBA)26 May