rdbms

I am a Java programmer who learns Haskell. I work on a small web-app that uses Happstack and talks to a database via HDBC. I've written select and exec functions and I use them like this: module Main where import Control.Exception (throw) import Database.HDBC import Database.HDBC.Sqlite3 -- just for this example, I use MySQL in production main = do exec "CREATE TABLE IF NOT EXISTS users (name VARCHAR(80) NOT NULL)" [] exec "INSERT INTO users VALUES ('John')" [] exec "INSERT INTO users VALUES ('Rick')" [] rows <- select "SELECT name FROM users" [] let toS x = (fromSql x)::String let names = map

I wonder how Object Oriented data modeling is different from Object Relational data modeling? Is it something like the pluses of both object oriented and relational data modeling were clubbed to achieve object relational data modeling? cheers Object-Relational data modeling supports some object-oriented concepts, while still supporting some relational concepts: Inheritance -- one table can have an IS-A relationship with another table. Likewise custom data types support inheritance. Distinction between a class and an object (instance of a class) that goes beyond simply the distinction between a

Is there a database out there that gives you the benefit of referential integrity and being able to use a SQL type language for querying, but also lets entities be loosely defined with respect to their data attributes and also the relationships between them? E.g. take a RBAC type model where you have Permissions, Users, User Groups & Roles. A complex/flexible model could have the following rules: Roles can have one or more permissions and a permission can belong to one or more Roles Users can have one or more permissions and a permission can belong to one or more Users Users Groups can have

From what I understood, Hadoop is a distributed storage system thingy. However what I don't really get is, can we replace normal RDBMS(MySQL, Postgresql, Oracle) with Hadoop? Or is Hadoop is just another type of filesystem and we CAN run RDBMS on it? Also, can Django integrated with Hadoop? Usually, how web frameworks (ASP.NET, PHP, Java(JSP,JSF, etc) ) integrate themselves with Hadoop? I am a bit confused with the Hadoop vs RDBMS and I would appreciate any explanation. (Sorry, I read the documentation many times, but maybe due to my lack of knowledge in English, I find the documentation is a

I'm trying to decide on the best way to model a relationship of records in a relational database. It's the classic friend/follow model: ~~~~ A User can have zero to many friends. A User can have zero to many followers. Friends and followers are both Users themselves. ~~~~~ What's the best way to model this? Thanks! Users (UserId, ...) Subscription (Subscriber, Publisher) Friendship (FirstUser, SecondUser) CREATE TABLE Users ( UserID int not null primary key, ... ) CREATE TABLE Subscription ( Subscriber int not null references Users(UserID), Publisher int not null references Users(UserID),

Two points I don’t understand about RDBMS being CA in CAP Theorem : 1) It says RDBMS is not Partition Tolerant but how is RDBMS any less Partition Tolerant than other technologies like MongoDB or Cassandra? Is there a RDBMS setup where we give up CA to make it AP or CP? 2) How is it CAP-Available? Is it through master-slave setup? As in when the master dies, slave takes over writes? I’m a novice at DB architecture and CAP theorem so please bear with me. A lot of databases now actually have different configurations and depending on the settings you set, it can be either CA, CP, AP, etc but can