Something that has been puzzling me for a bit now, and an hour or two of googlin' hasn't really revealed any useful answers on the subject, so I figured I'd just write the question. When I create a database in SQL using 'CREATE DATABASE DBNAME' am I implicitly creating a catalog in that database? Is it proper to refer to that 'DBNAME' a...
Taking a peak into the 'information_schema' database and peaking at the metadata for one of my pet projects, I'm having a hard time understanding what (if any) differences there are between the 'create schema' command and the 'create database' command for MySQL. Are there any differences? If not, is this a rather typical pattern of beha...
I need to develop a graph database in python (I would enjoy if anybody can join me in the development. I already have a bit of code, but I would gladly discuss about it). I did my research on the internet. in Java, neo4j is a candidate, but I was not able to find anything about actual disk storage. In python, there are many graph data m...
What are the differences between all of the different tpye of SQL? i hear of PostgreSQL, SQLite, MySQL, SQL, .... What are the differences between them? ...
if the dgree of an entity is 8. What is the minimum number of attributes required to form the primary key??...Thanks..... ...
Just had a discussion at work about the merits of using PostgreSQL over MySQL and vice-versa. Does anyone have any practical experience where there is a valid reason to use one over the other? Some people were saying that Postgre is better for security purposes whereas MySQL is becoming more feature rich... I'm not sure what to make of...
I'm taking an intro class on database management systems, and had a question that wasn't answered by my book. This question is not from my homework, I was just curious. The textbook continually stresses that a transaction is one logical unit of work. However, when coming across the shared/exclusive locking modes, I got a little confused...
How are varchar columns handled internally by a database engine? For a column defined as char(100), the DBMS allocates 100 contiguous bytes on the disk. However for a column defined as varchar(100), that presumably isn't the case, since the whole point of varchar is to not allocate any more space than required to store the actual data va...
I am looking for free DBMS options for a localhost environment, which will support migrating data and database objects (e.g. stored procedures, table definitions) to a DB2 9.5 installation. We can't use DB2 in localhost due to cost/licensing constraints, but would benefit from each developer having his/her own database to use locally. ...
Hi I want to learn DBMS including the concepts of complex SQL writing and normalisation and other stuff. Can anyone please help me to find some useful online resources..... ...
I am writing a simple app with 24 items in a hash to be persistent across program executions, so Berkeley DB (DBM) should be well suited for this task. And it is just for fun. But I wonder if using it (with Ruby), then when the user presses CTRL-C, then the execution is stopped. In this case, can't the data be all messed up? For exa...
which book is better to learn dbms... Elmasri & Navathe or Raghu Ramakrishnan ??? ...
While working on a project that will store a whole bunch of (completely different) forms I'm facing a design issue on how to store the values while keeping the database usable. Brief description: each 'document' contains a variable amount of questions (though a consistent amount per type of document) and matching answers. The most usab...
I've looked through all the "related questions" with two or three different titles and didn't see anything, so here goes. I've used SQL Server and Oracle in the recent past at work. I want to futz around at home, mostly with Java, perhaps with Ruby on Rails or Python. I'm running Windows 7. I usually make web applications, might like...
Hi! I'm trying to find a way to match a query to a regular expression in a database. As far as I can tell (although I'm no expert), while most DBMS like MySQL have a regex option for searching, you can only do something like: Find all rows in Column 1 that match the regex in my query. What I want to be able to do is the opposite, i.e.:...
I have quite long query with 'Q()', with Sqlite3 works very well, but with postgresql or mysql I have strange error e.g. for postgresql: invalid input syntax for integer: "(" and for mySQL: Truncated incorrect DOUBLE value: '(' How could I run that query with mysql? Where is my mistake? Here is that query: watchersTuple = self.getWa...
I need a DBMS, but do not know which to choose. Basically, the application makes many INSERT / UPDATE, but also many SELECT. SELECT mostly very simple, one field only. I am using MySQL + InnoDB at the moment, but as the database is growing, I need the best solution. The table can grow indefinitely, and the time +- 2GiB EDIT: Will run ...
What is the best opensource java integrated DBMS to store HTML pages? ...In term of performance, scalability, usability and more... thanks to all ...
I want to learn database management system on my own,would you like to suggest me some tips ...
i need to know the most popular dbms system which is available ...