{"id":20,"date":"2008-06-15T12:57:01","date_gmt":"2008-06-15T07:27:01","guid":{"rendered":"http:\/\/www.tothenew.com\/blog\/?p=20"},"modified":"2016-12-19T14:35:16","modified_gmt":"2016-12-19T09:05:16","slug":"how-to-use-table-per-subclass-inheritance-strategy-instead-of-table-per-hierarchy","status":"publish","type":"post","link":"https:\/\/www.tothenew.com\/blog\/how-to-use-table-per-subclass-inheritance-strategy-instead-of-table-per-hierarchy\/","title":{"rendered":"How to use table-per-subclass inheritance strategy instead of table-per-hierarchy"},"content":{"rendered":"

In this blog I want to share how to use table per sub-class<\/strong> instead of table per hierarchy, which is the default mechanism provided by Grails<\/a>.<\/code> I am not sure why Grails chose to use “table-per-hierarchy’. I always find it difficult to understand the table structure produced by “table-per-hierarchy<\/strong>“. Moreover, it makes things difficult for other non-grails application which need to read data from the data database. Another disadvantage is that columns cannot have a \"Not Null\"<\/code> constraint applied to them at the db level.<\/p>\n

If you are like me and prefer to use a table-per-subclass <\/code><\/strong>inheritance strategy, it can be easily achieved using fantastic Grails GORM DSL.<\/p>\n

Simply include the following code in all your Grails domain classes.<\/p>\n

   static mapping = {\r\n   tablePerHierarchy false\r\n}<\/pre>\n
This can be simply specified at the root class level and does-not need to be specified for all sub-classes in the hierarchy.<\/p>\n
Hope this helps.<\/p>\n","protected":false},"excerpt":{"rendered":"
In this blog I want to share how to use table per sub-class instead of table per hierarchy, which is the default mechanism provided by Grails. I am not sure why Grails chose to use “table-per-hierarchy’. I always find it difficult to understand the table structure produced by “table-per-hierarchy“. Moreover, it makes things difficult for […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"iawp_total_views":26,"footnotes":""},"categories":[7],"tags":[29,4840],"class_list":["post-20","post","type-post","status-publish","format-standard","hentry","category-grails","tag-gorm","tag-grails"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t