I understand that the question needs a lot of context to be answered properly but I was wondering if, as a general principle, was it better to have a small (10-100 bytes) or big (say >1k) average row size. If I know that right the physical storage is hit every time a new page is required so, I thought, having a small average row size mea...
I am looking to improve the performance of a query which selects several columns from a table. was wondering if limiting the number of columns would have any effect on performance of the query. ...
My organization is thinking on using an open source DBMS (free if possible, but not mandatory) for all new apps that we develop. Since we already have quite a few apps that connect to an oracle server, we would like to use a DBMS that is as compatible as possible with Oracle. So we can port the apps to oracle with the less work in the ca...
What is a "database manager" in the context of a DBMS? Please provide examples. ...
Another question on SO suddenly got me wondering what the largest database in the world is (and how big it could be). A quick Google search turned up this: the NSA call database, created by the U.S. National Security Agency. Supposedly this database contains over 1.9 trillion records containing details relating to phone calls placed thro...
Hiya. I have a script that parse the database and create php classes to work with that db. (zend-db-model-generator). is there a way to in php to have a DBMS agonstic commands so on each type of db it will return the table structure ? so it doesn't matter if i use the pdo driver once for mysql and once for postgresql, it will still ret...
Some time ago i was reading an article about new MS DBMS technology. It's some kind of OLAP but on the fly. This technology can bind to data flows and then provide a real time aggregation. So the question is "what is it's name?". I need such a technology now but can't remember it's name... Or maybe there are some similar technologies? ...
I have a database containing a single huge table. At the moment a query can take anything from 10 to 20 minutes and I need that to go down to 10 seconds. I have spent months trying different products like GridSQL. GridSQL works fine, but is using its own parser which does not have all the needed features. I have also optimized my databas...
Reading about WPF and thinking about my application's data store at the same time led me to wonder if there are any languages or tools that allow you to define relational data in a declarative way? A shallow Google search suggests no such thing exists. Yet it seems so obviously useful. The kind of tool I have in mind would declaratively...
Hi! I have huge database (kinda wordnet) and want to know if it's easier to use Cassandra instead of MySQL|PostrgreSQL All my life I was using MySQL and PostrgreSQL and I could easily think in terms of relational algebra, but several weeks ago I learned about cassandra and that it's used in Facebook and Twitter. Is it more convenient? ...
Hi. I want to develop a multiuser supporting accounting management application in C#. I want to use Linq To SQL classes. LINQ to SQL only supports SQL Server/Compact. However is it possible the SQLite people have written their own LINQ provider given the name of the assembly. I have to use DBMS that is FREE. Which DBMS do you suggest...
Please explain, in plain English, what question this SQL query answers: SELECT SUM(price) FROM Room r, Hotel h WHERE r.hotelNo = h.hotelNo and hotelName = 'Paris Hilton' and roomNo NOT IN (SELECT roomNo FROM Booking b, Hotel h WHERE (dateFrom <= CURRENT_DATE AND dateTo >= CURRENT_DATE) AND b.hotelNo = h.hotelNo AND hotelName = 'Paris ...
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?. ...
Hey guys, As a personal project, I'm looking to build a rudimentary DBMS. I've read the relevant sections in Elmasri & Navathe (5ed), but could use a more focused text- something a bit more practical and detail-oriented, with real-world recommendations- as E&N only went so deep. The rub is that I want to play with novel non-relational ...
Hey guys, I'm working on a basic DBMS as a pet project and planning to prototype in Python. I figure there's a reason there are only a few Python databases, and my gut agrees that my favorite language will be too slow to act as an honest performing database, but I'm looking forward to using it to learn what I need quickly. Would someo...
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...
In SQL, it is obvious that whenever we want to do a search on millions of record, say CustomerID in a Transactios table, then we want to add an index for CustomerID. Is another situation we want to add an index to a field when we need to do inner join or outer join using that field as a criteria? Such as Inner join on t1.custumerID = t...
can anyone tell me How does jdbc work? How it manages to communicate with a DBMS? since DBMS may be written with some other programming language. ...
Why are there so many Database management systems? I am not an DB expert and I've never thought about using another Database other than mySQL. Programming languages offer different paradigms, so it makes sense to choose a specific language for your purpose. Question What are the factors in choosing a specific Database management syste...
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? ...