rdbms

what really are database Constraints?

What really is constraints? Why i need to know about them? What are the types of constraints? ...

Have you used Intersystems Caché? What is your experience?

I came across few claims that usage of CacheDB instead of prooven RDBMS. But I couldn't understand how it is better than RDBMS? if so, why do they prefixed with Cache? Is it RDBMS or Caché server? Could you write brief notes about the use-case in your project? ...

Practical size limitations for RDBMS

I am working on a project that must store very large datasets and associated reference data. I have never come across a project that required tables quite this large. I have proved that at least one development environment cannot cope at the database tier with the processing required by the complex queries against views that the applicat...

Why use NoSQL over Materialized Views?

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,...

what are the uses of the different join operations in sql

what are the uses of the different join operations in sql? Like i want to know why do we need the different inner and outer joins? ...

What alternatives do I have if I want a distributed multi-master database?

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 store will handle this b...

When we say dbms is it files?

Hi all, when we say rdbms that means it may be oracle, my sql, ms access etc.. But for dbms what are the examples. Is there any example or it just the concept?. ...

Reasons for & against a Database

Hi, i had a discussion with a coworker about the architecture of a program i'm writing and i'd like some more opinions. The Situation: The Program should update at near-realtime (+/- 1 Minute). It involves the movement of objects on a coordinate system. There are some events that occur at regular intervals (i.e. creation of the obje...

When NOT to use Cassandra?

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. ...

Oracle Unique Indexes

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 SYS_C0065645. ...

Revisions: algorithm and data structure

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 change property of an object....

Calling an Oracle PL/SQL procedure with Custom Object return types from 0jdbc6 JDBCthin drivers

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 ...

Are products like SQL Server and Oracle are "ORDBMS"?

According to wikipedia! http://en.wikipedia.org/wiki/ORDBMS IBM's DB2, Oracle database, and Microsoft SQL Server, make claims to support this technology and do so with varying degrees of success So, are these products true "ORDBMS" like PostgreSQL? or they are they are long way from it? can someone plz! point me to any ...

Do we need Record Level Locking when we already have Transaction for online ordering? (of concert ticket or airline booking)

For online ordering of concert seats or airline tickets, 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 showing the ticket purchase scre...

Database for Python Twisted

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 directly m...

Database design question

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 after collecting fare from them. Passengers travel from a variou...

SimpleDB as backup?

Hi, Is there any solution (RDBMS or NoSQL) that can use SimpleDB as a backup? Thanks, A. ...

NoSQL: How to retrieve a 'house' based on lat & long?

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 zzz Q...

What's the difference been NoSQL and a Column-Oriented 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)? ...

Database/NoSQL - Lowest latecy way to retreive the following data...

I have a real estate application and a "house" contains the following information: house: - house_id - address - city - state - zip - price - sqft - bedrooms - bathrooms - geo_latitude - geo_longitude I need to perform an EXTREMELY fast (low latency) retrieval of all homes within a geo-coordinate box. Something like the SQL below (...