Zend Framework Blog » Foreign keys http://blog.richardknop.com Zend Framework, PHP, Django, Python, SQL, MySQL, PostgreSQL, Oracle, PL/SQL, data model patterns, OOP, design patterns, JavaScript, jQuery, HTML, XHTML, CSS, XML, web services & APIs, Security, E-commerce and much more Sat, 04 Feb 2012 19:47:10 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 #1005 – Can’t create table ‘database_name.table_name’ (errno: 150) http://blog.richardknop.com/2009/07/1005-cant-create-table-database_name-table_name-errno-150/ http://blog.richardknop.com/2009/07/1005-cant-create-table-database_name-table_name-errno-150/#comments Sun, 19 Jul 2009 22:20:40 +0000 Richard Knop http://blog.richardknop.com/?p=444 When you are working with MySQL InnoDB table engine and especially foreign keys (as I do) you will encounter a similar error message quite often. Tracking down where exactly lies the problem can be very frustrating as the error message isn’t very suggestive.

From my experience, the problem is 99% of the time with foreign keys. Here are three most common reasons I have come across:

  • the two fields in the foreign key relationship are not exactly the same type (for example one is TEXT and another is VARCHAR)
  • although the two fields are the same type they aren’t the same size (for example one is INT(10) and another is INT(4))
  • the field you are referencing with the foreign key has no index (if the field is not a primary key you must add index to it)

I hope this might be helpfull to someone who comes across a similar error message.

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