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35
votes
11answers
1k views

Why don't relational databases support returning information in a nested format?

Suppose I'm building a blog that I want to have posts and comments. So I create two tables, a 'posts' table with an autoincrementing integer 'id' column, and a 'comments' table that has a foreign key ...
15
votes
4answers
1k views

Why many designs ignore normalization in RDBMS?

I got to see many designs that normalization wasn't the first consideration in decision making phase. In many cases those designs included more than 30 columns, and the main approach was "to put ...
13
votes
5answers
927 views

Why is filesystem preferred for logs instead of RDBMS?

Question should be clear from its title. For example Apache saves its access and error logs in files instead of RDBMS no matter on how large or small scale it is being utilized. For RDMS we just have ...
9
votes
4answers
319 views

Do these specific tables need surrogate keys?

Background I have this tables +-------------------------+ +------------------------+ |Airport | |Country | |-------------------------| |------------------------| ...
8
votes
2answers
352 views

Is there a canonical source supporting “all-surrogates”?

Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. ...
8
votes
3answers
4k views

Why aren't Object Oriented databases used as much as Relational Databases? [closed]

I have come across many relational database management systems (RDBMS). But recently I used hibernate which made me start wondering why Object Oriented databases aren't more popular. If object ...
8
votes
5answers
4k views

When not to use ORM and prefer stored procedures?

I am using PetaPoco micro-ORM. It is indeed very easy and secure to work with databases using ORM tools, but the only thing I hate is extra code. I used to put most of the code in the database itself ...
8
votes
7answers
577 views

Should a surrogate key ever be exposed to a user?

Often in a table that has no natural key, it is still useful for users to be able to have a uniquely generated identifier. If the table has a surrogate primary key (and in such a case you would ...
7
votes
5answers
1k views

Predicting advantages of database denormalization

I was always taught to strive for the highest Normal Form of database normalization, and we were taught Bernstein's Synthesis algorithm to achieve 3NF. This is all very well and it feels nice to ...
7
votes
3answers
228 views

Are there best practices for checking for errors in business logic for DB refreshes? [closed]

I'm working for a company with very large databases which all refresh overnight, ready for users to interrogate in the morning. These over night loads essentially truncate all the tables, and reload ...
6
votes
8answers
1k views

Why can't SQL return joined tables in a nested format?

For example, say I want to fetch a User and all of his phone numbers and email addresses. The phone numbers and emails are stored in separate tables, 1-user to many phones/emails. I can do this quite ...
6
votes
3answers
358 views

choosing a functional language platform for a new project [closed]

I have been writing code for a few years now and I don't believe I can claim to have a complete knowledge in this job yet. My experience primarily rolls around C# related areas with a decent ...
5
votes
1answer
303 views

What's a good scheme for multi-user database synchronization?

I'm working on a system to allow multiple users to collaborate on an online project. Everything is fairly straightforward, except for keeping the users in sync. Each user has their own local copy of ...
4
votes
2answers
389 views

In what order are rows fetched absent ORDER BY clause?

One programmer is testing and comparing the same application which uses the same database structure, and the same data, only in two separate databases, one with Oracle 8 and one with Oracle 9. The ...
4
votes
3answers
331 views

Rule of thumb for field sizes

What VARCHAR sizes should be used for first and last names, phone numbers (preferably international), email adresses, urls, dictionary words and file names? Edit: Zapped the introductory phrase to ...
4
votes
2answers
474 views

ORM domain design pitfalls

Are there any patterns which seem sensible when designing an object oriented domain, but do not translate nicely onto a relational database schema? If so, are there standard patterns that can be used ...
2
votes
2answers
124 views

Lucene + Joins == RDBMS?

Now that Lucene supports joins (at indexing time and at querying time) can one use Lucene as a databse (a NoSQL one, with Eventual Consistency)? Note: I was pondering on that for sometime and this is ...
1
vote
6answers
2k views

flat files vs. RDBMS database, few read/writes, few changes

I have to handle data from long term (years, decades) climate monitoring stations. The data flow usually starts with raw data (voltages, etc.) plus quality check information (pressure, temperature, ...
1
vote
2answers
255 views

Are there any advantages of using separate RDBMS for reports?

My production database is SQL Server 2008 R2 Express. It has limited features and I am testing it in a production environment. To better handle reporting queries in a highly concurrent environment, I ...
1
vote
1answer
59 views

How is data integrity maintained in a clustered environment when schema changes?

Scenario A clustered environment running N identical application nodes interacting with a single relational database. Problem Is it possible to upgrade the nodes to a new application version, which ...
1
vote
1answer
78 views

How to compare and relate together the concept of DBMS to the concept of Cloud Storage system? [closed]

I am a student of Computer Science and I am writing my disseration on a Cloud Storage application developed in the company for wich I work. My problem is the following one: my supervisor (the teacher ...
0
votes
2answers
217 views

Why should a column in a Relational Database have a single purpose?

Consider a table in which a column represents a monetary value in some cases and a link to the value of another record in other cases so that we have the following: TABLE 1 Id Product Composite 1 ...
0
votes
3answers
122 views

Desktop GUI Client - Remote RDBMS communication

Sorry if I am asking a trivial question but I have been searching for a while without any luck. I need to design a system and I am looking for advice on the technology that should be used. The layout ...
0
votes
1answer
275 views

Will SSD make the distinction between column oriented DB and row oriented DB obsolete? [closed]

I had a discussion with a friend about row vs column oriented RDBMS. From my understanding, these things are closely linked with the fact that there's a concrete drive head reading and writing the ...
0
votes
2answers
913 views

Why is the Unit of Work pattern considered fast and efficient when working with an ORM?

In working with Doctrine 2 I came across the following paragraph. In fact, since Doctrine is aware of all your managed entities, when you call theflush() method, it calculates an overall ...
0
votes
1answer
258 views

RDBMS same type of optional data for multiple tables

I have an embedded database (SQLite), it stores information about events and page views, its purpose is to track the user journey inside my application. I need to provide support for optional custom ...
0
votes
0answers
35 views

Iterating calculations - children of children of children

I would like to move some business logic out of my application and into a stored procedure or function. I am willing to change rdbms as the system is being updated/re-written. Right now it's Access 97 ...
-1
votes
1answer
207 views

Use of file processing system like NTFS for file system of Operating System [duplicate]

While reading the advantages of RDBMS,over a file processing system(like NTFS,FAT 32),I had a question in mind: The popular operating systems(like Windows) continue to use file processing systems(like ...
-2
votes
1answer
3k views

How to draw an E-R diagram?

I am learning DBMS in my college. Recently I was given an assignment to draw a E-R Model of a Bus Reservation system which handles Reservations, Ticketing and cancellations. I understand the theory ...