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MySQL inconsistently altering name of indexes associated with foreign keys on InnoDB tables


By : Tyronusana
Date : October 16 2020, 06:10 PM
Hope this helps I have noticed the same thing, but I've never seen any official documentation that explains this.
I agree it seems like InnoDB "knows" which indexes were created implicitly and which were created explicitly. But I don't know where it tracks this information. InnoDB exposes much of the metadata in INFORMATION_SCHEMA tables, but it must store more information in the internal data dictionary.
code :


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Is it possible to use Mysql foreign keys in InnoDB tables for inverse lookup?


By : Maria C. Calixto
Date : March 29 2020, 07:55 AM
this one helps. I wonder if it is possible to use FK's in Mysql (InnoDB) for inverse lookup. , After reading up a lot, one option would be to use something like:
code :
SELECT
  referenced_table_name parent,
  table_name child,
FROM
  information_schema.KEY_COLUMN_USAGE
WHERE
  referenced_table_name IS NOT NULL

Row locking in MySql InnoDb with foreign key constraints and indexes applied?


By : user2548757
Date : March 29 2020, 07:55 AM
I wish this helpful for you I wrote a blog post on this - http://www.mysqlperformanceblog.com/2010/09/20/instrumentation-and-the-cost-of-foreign-keys/ - the demo is just as your friend described. There is locking on parent rows!
Now for the part about explaining the difference between an "index" and a "key":

Setting up MySQL foreign keys and indexes - Migrating to InnoDB


By : christopher
Date : March 29 2020, 07:55 AM
wish of those help
Is this possible to do with foreign keys or will I have to do the verification in the programming language of my choice?

Foreign keys for myISAM and InnoDB tables


By : VadimIgnatuev
Date : March 29 2020, 07:55 AM
like below fixes the issue http://dev.mysql.com/doc/refman/5.0/en/innodb-foreign-key-constraints.html
Foreign keys definitions are subject to the following conditions:

Mysql error: 1215 Cannot add foreign key constraint[ foreign keys same type, innodb ]


By : Joy elalam
Date : March 29 2020, 07:55 AM
Does that help As the others stated in comments, your queries are correct
Couple of things you can try :
code :
USE `spring_normalize`;


CREATE TABLE IF NOT EXISTS `users` (
  `username` VARCHAR(60) NOT NULL,
  `password` VARCHAR(80) NULL,
  `authority` VARCHAR(45) NULL,
  `name` VARCHAR(100) NULL,
  `enabled` TINYINT(1) NULL,
  `email` VARCHAR(60) NULL,
PRIMARY KEY (`username`))
ENGINE = InnoDB;

CREATE TABLE IF NOT EXISTS `offers` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `text` VARCHAR(100) NULL,
  `users_username` VARCHAR(60) NOT NULL,
PRIMARY KEY (`id`, `users_username`),
INDEX `fk_offers_users_idx` (`users_username` ASC),
CONSTRAINT `fk_offers_users`
  FOREIGN KEY (`users_username`)
  REFERENCES `users` (`username`)
  ON DELETE NO ACTION
  ON UPDATE NO ACTION)
ENGINE = InnoDB;
-- Do not check foreign key constraints
SET FOREIGN_KEY_CHECKS = 0;
SHOW ENGINE INNODB STATUS;
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