Re: Database Design

Hi Sach,

    I have implemented systems similar to what you are describing in the past. The major difference is that I kept the jpegs, gifs, etc outside of the database.

    I used Oracle as a great big table of contents and index system. User queries ran against the Oracle database and returned a list of candidates to the user. The user then selected one or more candidates which the system retrieved for the user.

    From a design standpoint it doesn't matter if the jpegs, gifs, etc are stored in the database as blobs or kept in Unix files outside of the database.

    The trick is in how you build your table of contents and index structures. In my case I had to support a tree with many-to-many relationships in both directions. I wound up cheating. My tables were all built using one-to-many relationships. Each row had the id of its parent as well as the descriptive information about the item.

    Using this scheme descending the tree is a relatively slow operation. Since the table has no hierarchy what you have to do is find a row and then find all of the rows where the row you initially found is a parent. This process is repeated for each level you descend in your structure. Even with indexes on both parent_id and item_id this technique can result in a substantial amount of disk activity.

regards

Jerry Gitomer

spotdar_at_nsf.gov wrote in message <36DAF6A0.580A9C1_at_nsf.gov>...
>Hi everyone
> First of all, I am new to database design. I have never done any
>kind of database design before. Because of unforseen circumstances, I
>have been forced to design the database myself.
> Currently I have a web based system that is purely based on flat
>files. This system consists of a large number of .html, .pdf, .xls,
>.gif, .jpeg files. All of these files are organized in a hierarchical
>tree sturcture on a UNIX system. My job is to design an Oracle 8
>database to move all the files from the file system into the database.
>The current system is running on Solaris 2.6 with Apache web server.
>Oracle 8 database is going to run on Solaris 7.0 with Apache web server
>again.
> If there is anyone out there who has done similar kind of work or
>has some knowledge as how to approach this problem, I would really
>appreciate your response. Also any information on database design books
>will be helpful.
>
>Thanks
>
>Sach
>
Received on Tue Mar 02 1999 - 00:00:00 CET