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Diffstat (limited to 'doc/development/single_table_inheritance.md')
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diff --git a/doc/development/single_table_inheritance.md b/doc/development/single_table_inheritance.md new file mode 100644 index 00000000000..27c3c4f3199 --- /dev/null +++ b/doc/development/single_table_inheritance.md @@ -0,0 +1,18 @@ +# Single Table Inheritance + +**Summary:** don't use Single Table Inheritance (STI), use separate tables +instead. + +Rails makes it possible to have multiple models stored in the same table and map +these rows to the correct models using a `type` column. This can be used to for +example store two different types of SSH keys in the same table. + +While tempting to use one should avoid this at all costs for the same reasons as +outlined in the document ["Polymorphic Associations"](polymorphic_associations.md). + +## Solution + +The solution is very simple: just use a separate table for every type you'd +otherwise store in the same table. For example, instead of having a `keys` table +with `type` set to either `Key` or `DeployKey` you'd have two separate tables: +`keys` and `deploy_keys`. |