There has been a lot of talk related to Cassandra lately.
Twitter, Digg, Facebook, etc all use it.
When does it make sense to:
use Cassandra,
not use Cassandra, and
use a RDMS instead of Cassandra.
I'm writing some JDBC code which calls a Oracle 11g PL/SQL procdedure which has a Custom Object return type. I can get the code to call the procedure, but how do I access the returned Custom Object to obtain it's contained values?. An example of my code calling the procedure is below:
PLSQL Code:
Procedure GetDataSummary (p_my_key IN …
There has been a lot of talk recently about NoSQL.
The #1 reason why I hear people use NoSQL is because they start to de-normalize their DBMS data so much so, to increase performance, that they end up with just one table with all of their data within that single table.
With Materialized Views however, you can keep your data normalized, yet…
I'm writing some JDBC code which calls a Oracle 11g PL/SQL procdedure which has a Custom Object return type. Whenever I try an register my return types, I get either ORA-03115 or PLS-00306 as an error when the statement is executed depending on the type I set. An example is below:
PLSQL Code:
Procedure GetDataSummary (p_my_key IN …
Hi!
I'm using a nested set in a MySQL table to describe a hierarchy of categories, and an additional table describing products.
Category table;
id
name
left
right
Products table;
id
categoryId
name
How can I retrieve the full path, containing all parent categories, of a product? I.e.:
RootCategory > SubCategory 1 >…
Hi, I wonder if there is a canonical way to convert data from long to wide format in SQLite (is that operation usually in the domain of relational databases?). I tried to follow this example for MySQL but I guess SQLite does not have the same IF construct... Thanks!
I have a NoSQL system for storing real estate houses.
One piece of information I have in my key-value store for each house is the longitude and latitude.
If I wanted to retrieve all houses within a geo-lat/long box, like the SQL below:
SELECT * from houses WHERE latitude IS BETWEEN xxx AND yyy
AND longitude IS BETWEEN www AND…
There's an API for Twisted apps to talk to a database in a scalable way: twisted.enterprise.dbapi
The confusing thing is, which database to pick?
The database will have a Twisted app that is mostly making inserts and updates and relatively few selects, and then other strictly-read-only clients that are accessing the database…
The more I read about NoSQL, the more it begins to sound like a column oriented database to me.
What's the difference between NoSQL (e.g. CouchDB, Cassandra, MongoDB) and a column oriented database (e.g. Vertica, MonetDB)?
My concern is about what I currently call "dictionary tables", that are database tables
containing a list of controlled vocabulary.
Let's use an example:
Suppose you have a table User containing fields:
user_id : primary key
first_name
last_name
user_type_id : foreign key to the UserType table
and another table UserType…
I was creating a new table today in 10g when I noticed an interesting behavior. Here is an example of what I did:
CREATE TABLE test_table ( field_1 INTEGER PRIMARY KEY );
Oracle will by default, create a non-null unique index for the primary key. I double checked this. After a quick check, I find a unique index name…
Hi All,
I am using Hibernate 3 as my persistence framework.
Below is the sample hbm file I am using.
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
…
Hi All,
We're evaluating MySQL and PostgreSQL for building our indic language web application which will use MySQL or PostgreSQL.
One of my colleagues mentioned that MySQL had issues with i18n. I mostly come from the Oracle world and although I've played a lil with MySQL, I don't know enough to know that there are…
I will build a system where I want to reduce single-point-of-failures, and I need a database. Is there any (free) relational database systems that can handle multi-master setups good (i.e where it is easy to add and remove nodes) or is it better to go with a NoSQL-database?
As what I have understood, a key-value…
Where does current technology fall short of industry demands in the context of data and information management?
In other words, where should the software engineering industry as a whole be focusing its efforts in these areas?
Hi, I need ideas for structuring and processing data with revisions.
For example, I have a database of objects (e.g. cars). Each object has a number of properties, which can be arbitrary, so there's no a set schema to describe these objects. These objects are probably saved as key-value pairs.
Now I need to…
For online ordering of concert seat or airline ticket, do we need Record Level Locking or is Transaction good enough?
For concert ticket (say, seat Number 20B), or airline ticket (even with overbooking, the limit is 210, for example), I think the website cannot lock any record or begin transaction when…
I have been putting off developing this part of my app for sometime purely because I want to do this in a circular way but get the feeling its a bad idea from what I remember my lecturers telling me back in school.
I have a design for an order system, ignoring the everything that doesn't pertain to…
A few questions on MS Access databases -
Size: Are there limits to the size of an access database? The reason i ask is that we have an access database that has a few simple tables. The size of the db is about 1GB. When I do a query on it, i see it taking over 10 minutes to run.
With proper…
Hi everybody,
I have thought a bit about sharding tables, since partitioning cannot be done with foreign keys in a mySQL table. Maybe there's an option to switch to a different relational database that features both, but I don't see that as an option right now.
So, the sharding idea seems like…
Hi
I need some advice regarding multiple records. I have a table with fields username,*message* and message_to. the scenario could be of sending same message to multiple users in a go. What do you suggest? will it be efficient to save all recipients in a single column with comma separated…
Is there a tool that implements hyperlink-style navigation between tables via foreign keys? Web-based or native app.
For example, if I have table Users, with a column containing a foreign key reference to table Preferences, such a tool would implement simple 1-click access between the…
Hi Team,
I have an interesting database design problem that I formulated while travelling by a bus, coming back from my home.
Design a normalized database for a bus ticketing system (not reservation system). In each trip, the conductor of the bus will give tickets to its passengers…
If you had a webshop solution based on SQL Server relational DB what would be the reasons, if any, to move to NoSQL storage ? Does it even make sense to migrate datastores that rely on relations heavily to NoSQL? If starting from scratch, would you choose NoSQL solution over…
Hey,
I got a user table containing 15+ million records and while doing the registration function i wish to check whether the username already exist. I did indexing for username column and when i run the query "select count(uid) from users where username='webdev'" ,. hmmm,…