How to store objects in a database for retrieval

Question

I am trying to create a database that can be used to store lots of objects. I was trying to do this with a relational database however it seems to be a bit of a beast. I mean take the simple object below

Object = {
   "Type":"Car",
   "Color":"Green",
   "Doors":3,
   Wheels:{
       "Material":"Alloy",
       "Size":17,
       "Color":"Black",
       "Tyres":{
          "Profile":"Low",
          "Material":"Rubber"
          "Tread":"Slick"
       }
   },
   Seats:{
       "Number":2,
       "Seatbelts":true
   }
}

From these you could picture a 3 door green car, with black 17inch alloy wheels, low profile, slick rubber tyres, 2 seats with seatbelts. Obviously, this whole object is not set in stone, you could go and then expand upon things

(eg.

Seatbelt:{
    "Type":"Harness",
    "Buckles":1,
    "Color":"Blue"
}

)

Eventually, assuming there are a lot of objects, I would want to return a list of objects that have these characteristics

{
"Type":"Car"
"Doors":3
}

From this I may get a list of 5 cars back that have 3 doors but have various other attributes, it doesn't matter, I haven't specified these criteria. I could narrow it down further, looking for all 3 door cars with slick tyres... I might get back 2

{
   "Type":"Car"
   "Doors":3
   "Wheels":{
      "Tyres":{
         "Tread":"Slick"
      }
   }
}

So I was thinking a database having 3 main tables: objects, attributes and values. Then having linking tables, linking objects to attributes, attributes to values. However, what if, like in the example I have objects containing objects, and also if I plan on having an object of car which the example could be an extension of?

How do we deal with this type of database problem? Can it be done with a relational database or do I need an object oriented one? If so, are there any OODBs that I can implement with a website as easily as I can MySQL.

If you can use a RDB to do this, then queries, surely they would be very resource intensive? How about OODBs? As resource intensive?

How can I make a Object Oriented DB for a website? using RDB or OODB, I don't mind, it's just how

Answer 1

I would take a look at hibernate (for Java) or nhibernate (for .net). http://www.hibernate.org

Hibernate provides ORM (Object Relational Mapping) for relational databases (like MySql)

Another solution (which I personally don't like) for small amounts of data are xml files, you can then parse the data with xpath expressions. http://www.w3schools.com/xpath