I have a table, say orders, which has a column, say a alphanumeric 15 character long itemId and a bunch of other columns. The same itemId can be repeated say up to 900 times for very popular items, which means the data will be repeated about 900 times. Obviously, we need to separate it out. However, we need the lookup for the list of items to be very quick and efficient. I read up a bit and thought reverse indexing would be a good way to achieve this. However, I am a bit confused on the actual implementation. I couldn't find any examples online as well other than http://blog.frankel.ch/tag/spring-data , but it uses solr. I was thinking of creating a items-orders table, adding a repository class which will have a method to . However, since there is many-many relation between items and orders, it will require a join table. This makes me think that i am on the wrong path as i intended items-orders table itself as a kind of join table as it only as itemId and orderId in it.
I am pretty sure I am doing something wrong. Any pointers are greatly appreciated. Sorry for a basic question, but I could not find much information with samples online.
thanks,
Alice
答案 0 :(得分：0)
You're on the right track with an item orders link table. You will probably find that you end up using the table for additional columns you haven't considered yet (quantity, price, etc.)
The main thing to do starting with is make sure your database design is right, look up the basic normalization rules about making sure you don't duplicate information. Also when you create your tables make sure you're explicitly telling the database of the the relationships between the tables using FOREIGN KEY and PRIMARY KEY constraints.
Once you have the correct logical structure in place you can see if you have any performance issues that require you to do anything clever.
Relational databases were designed to exactly what you're contemplating though so the performance will probably be much better than you fear. Premature optimization would be a huge mistake.
You mentioned solr, this is a generic text search engine (sort of like google). For your requirements you want to stick to a pure relational database. You want a base that delivers exact results based on exact criteria exactly what products have been included in an order etc. you don't want any fuzzy matching or artificial intelligence guessing about what has been ordered.
You might also store the product catalogue in solr so the user could pick look for products that mention pink,blue or purple in the description and comes in a size 4 etc, then once the product has been chosen use the itemId in the relational database.