Should we repeat multilevel dependency reference columns to avoid multiple joins breaking the normal forms for better performance

In general I know repeating information in tables are not considered a good database design But I have a question for following particular design for multi level parent child relationship Table_1_Table_2_Mapping - Id - Table_1_Id - Table_2_Id Table_2_Table_3_Mapping - Id - Table_2_Id - Table_3_Id I am just showing the two levels relationship here for example, but I have 5 levels of such parent child relation So with the current design (which I feel is the correct design following the database normal forms) if I have to traverse to Table 1 from Table 3 I have to go via Table 2 So this way Table_3 joins Table_2 join Table_1 This looks okay because they are just three tables, but what if I have to reach from Table_9 to Table_1, there will be more than 15 joins going from each mapping table to each main table. It it still worth to follow the normal forms in that case also if I have say 9 child parent tables? Or should I keep adding the repeating information in child mapping tables like this to keep the performance in mind (however this is not a good design as far as I know) Table_2_Table_3_Mapping - Id - Table_2_Id - Table_3_Id - Table_1_Id //added this id to go directly to Table_1 from Table_3 skipping Table_2 join