I've been stuck in a MsSql/MySql world now for a few years, and I've decided to spread my wings a little further. At the moment I'm researching which DBMS is good at things needed when archiving data. Eg. lots of writes and low reads. I've seen the NoSQL crusade, but I have a very RDBMS mindset, so I'm a bit skeptical. Anyone have any ...
When you hit a roof on reading from a database, you have two choices, scale vertically by putting more hardware in the server, or scale horizontally by putting a second server to help offload the reads. Offloading reads to a second server, means that all writes will hit both servers, while read only hits one. Problem is when you hit a...
Hi, I am sorry if my question sounds stupid but I want to know as per the theoretical definition of functional dependency, will {}-->A where {} is a NULL set and A is any attribute of the table. ...
Hello, I want to develop a POS application in .NET (C#) that would be used to rent items. I have a good idea of what will be done and the famous question that I have is about the DBMS that I should use. I would like to use MySQL database. The question is: If some places use only one computer (no network, no internet connection), can I ...
I really need a free database which supports encryption, but doesn't have size limitations like 4 GB in SQL Server Express. Suggestions welcome! ...
By what factor does the performance (read queries/sec) increase when a machine is added to a cluster of machines running either: a Bigtable-like database MySQL? Google's research paper on Bigtable suggests that "near-linear" scaling is achieved can be achieved with Bigtable. This page here featuring MySQL's marketing jargon suggest...
Hey, I'm learning an ecommerce package (Spree). The problem arises after I delete a product thru the GUI. I try to manually undo the delete by changing/adding rows back in, but I fail. My question is this: is there any way I can add application or dbms code/config/software to log transactions? Preferably, this will work with sqlite3,...
Stonebraker's paper (Operating System Support for Database Management) explains that, "the overhead to fetch a block from the buffer pool manager usually includes that of a system call and a core-to-core move." Forget about the buffer-replacement strategy, etc. The only point I question is the quoted. My understanding is that when a DBM...
There has been a lot of talk about contra-revolutionary NoSQL databases like Cassandra, CouchDB, Hypertable, MongoDB, Project Voldemort, BigTable, and so many more. As far as I am concerned, the strongest pros are scalability, performance and simplicity. I am seriously considering to suggest using some non-relational db for our next pr...
I have a FormView through which I set up the default new, update and delete commands for communicating with an SQL Server database. When the CREATE command is executed the data is added to the database and some images are uploaded to a server and linked to the database. Problem When I press the Visual Studio's default FormView DELETE ...
Hello everyone! My boss gave me a bunch of requirements that I'm not pretty sure about how to design them in the DBMS. Basically the user has to describe an object defining its attributes in an old fashion way: "key"=>"value". The problem is that the user has "free will" on choosing both keys and values so he can wrote whatever he wants ...
Hi there. I want to do the following: SELECT count(id) FROM table WHERE value BETWEEN 3 AND 40; But it should do the following: SELECT count(id) FROM table WHERE value IN(3, 4, 5, 6, 7, 8, 9, 10, 11, ..., 40); It should even print out zero count(id) for value between 3 and 40, but not value = x. I want to check if a value is in a s...
I want to put some same value in some fields where data is not present, for that do I need to query each field and see if there is data present or not and accordingly put the data, or there is some other work arround. Like Name Age City N 22 J K K 23 L Here I want to put data on those fi...
There are so many products which are rdbms like oracle,mysql,SqlServer etc.... But what about dbms related products?Is foxpro dbms ? ...
I want to know about Which language is best for long term career and How? Which language should I choose among Java and .NET Platform or Should I choose Oracle like DBMS Language (SQL/PLSQL)? I am confused? Detailed answer would be appreciated. ...
hi all i want to know that what actually dirty data means in dbms. how can be calculate degree of isolation of a transaction(programm)in dbms. ...
I would like to know when to actually use delete cascade or delete restrict AND update cascade or update restrict. I'm pretty confused using them or applying in my database. ...
I have a table called "downloads" with a few thousand rows. I just added a column called is_completed using the following command: ALTER TABLE downloads ADD is_completed BIT default 1 NOT NULL Now I would like to change the default value for is_completed to 0 - I tried this command to no avail: ALTER TABLE downloads MODIFY is_complet...
Possible Duplicate: When or why would you use a right outer join instead of left? What ever the functionality i get with left outer join i can get it by interchanging table names.Then, what is the need for having two outer joins ( left and right) ? If there is any specific need can some body explain with an example ? ...
If y is a subset of x then x-->y is trivial functional dependency(it is well known).But i have doubt: y is not subset of x and x U y = R, then can i say x-->y is a trivial functional dependency.( I read it in some article) Adding to above question: Why X U Y = R holds in case of multivalued dependencies(trivial).Can somebody give an ...