Relational Database Management System, a widely used type of database management system characterised by its extensive use of joining as a core operational principle.

learn more… | top users | synonyms

2
votes
1answer
321 views

Restriction on self referencing on insert in MYSQL?

How to restrict insert on adding self referencing rows in a recursive relation table (a table contains foreign key points itself). mysql> SELECT * FROM Employee; ...
3
votes
1answer
427 views

How to Update same table on deletion in MYSQL?

In my Database I have a table: Employee with recursive association, an employee can be boss of other employee. Following is query I used to create table: CREATE TABLE IF NOT EXISTS `Employee` ...
0
votes
1answer
116 views

How are transactions logs inserted?

I have an ms-access database at work that has a table that's a transaction log. The table contains the following fields: Date - The date the transaction took place. Table_Name - Name of the ...
10
votes
1answer
1k views

Commit vs Fast Commit vs Commit Cleanout in Oracle Database

I was wondering whether someone could verify my understanding regarding the differences between those 3 terms as pertaining to Oracle Databases. Many sources confuse these terms and do not explain ...
8
votes
2answers
351 views

How to modify an update in Oracle so it performs faster?

I have this query: UPDATE ( SELECT h.valid_through_dt, h.LAST_UPDATE_TMSTMP FROM ETL_FEE_SCH_TMP d, FEE_SCHEDULE_HISTORICAL h WHERE h.FUND_ID = d.FUND_ID AND ...
3
votes
1answer
395 views

Surrogate key / Primary key: Better to use an existing unique data field or create a key field?

I am not sure if this question has been asked or not. At least I couldn't find it. I am curious about a primary key in terms of efficiency with data searching and retrieval. This is a hypothetical ...
11
votes
3answers
1k views

Use MySQL to regularly do multi-way joins on 100+ GB tables?

Background: I’ve created a web application that I would like to be able to scale reasonably well. I know I'm not Google or Twitter, but my app uses a fairly large amount of data for each user and thus ...
1
vote
1answer
359 views

Which RDBMS best fits my need? [closed]

I realise this may be come a subjective mess, but I'm hoping for some objective information on the subject. I also don't want to go shopping, I just want to know 'what to shop for'. I'm very new to ...
1
vote
1answer
85 views

Storing many small - and a few large - strings in an RDBMS

Let's say I have a table, and (among other things) it needs to store a large number of strings. Most will be small (20-100 characters), but a few will be quite large. Reads will be frequent, writes ...
3
votes
1answer
60 views

Why isn't there a way to label a column as “keyword”

In a typical star schema, you end up with a bunch of columns that are an ID into some lookup table, where the lookup table is pretty much just this: create table hostnames ( id primary key, ...
1
vote
1answer
314 views

file not found - how to remove its configuration?

I run oracle 10.2.0.5. I have the following: SQL> select file#, status, error, recover, tablespace_name, name 2 from v$datafile_header 3 where recover='YES' 4 or (RECOVER IS NULL AND ...
2
votes
3answers
645 views

Which database is best for deeply embedded database or through C DLL?

I want a deeply embedded database. Deeply embedded means that the server is started by an application and closed by the application with no tcp/ip or 0 port. The main features of consideration are: ...
8
votes
2answers
5k views

PostgreSQL vs. MySQL - Advantages / Disadvantages with a spatial component

We are the in the process of building out a web application that has a spatial data component. In the beginning our spatial data comparisons will take a given point and return matched overlapping ...
0
votes
1answer
403 views

which DBMS should i go for? [closed]

I am interested in learning a DBMS. As a beginner which DBMS should i go for ? I know few DBMS by name like Oracle,Sql Server,My Sql . How are these DBMS different from each other ? As a beginner ...
1
vote
1answer
211 views

Is there an Oracle rdbms monitoring API?

We have about a thousand customers with our application installed out of which 500 have an oracle database. Monitoring the database is only one of the requirements. Installing Oracle Enterprise ...
4
votes
1answer
161 views

how much overhead an error in RDBMS has?

I have a class in my project. On the class I need to do two inner select, to know is there any duplication or not, but I think if I get duplication error and then manage that is better than to select. ...
2
votes
6answers
836 views

Is normalization process needed?

Well after learning DBMS as a subject i got so many questions in mind. Normalization is one of them. As i learnt it there was a lot more confusion and i found that whatever we do in normalization ...
12
votes
2answers
792 views

NoSQL and RDBMS together?

I was wondering if there are any good solutions for recording data in a NoSQL database and then converting them over to an RDBMS? For example, if you wanted to capture some data quickly, like ...
0
votes
4answers
6k views

What's a good client tool to access Oracle RDBMS? [closed]

I'm looking for a good client tool to replace "Oracle SQL Developer" (the tool I currently use) which supports: Oracle DB 10g, 10gR2, 11g Running SQL code Debugging SQL code (with walk-through... ...
6
votes
2answers
937 views

Single Drive vs Multiple Drives

Generally bottleneck of RDBMS (I am a MySQL user) performance is disk access. SSD provides great performance compared with conventional spindle drives. Question : Is it possible to improve ...
2
votes
3answers
1k views

How does an OLAP cube database differ from an RDBMS?

Is a cube database, simply an RDBMS—such as PostgreSQL or MySQL—configured for OLAP via a star or snowflake schema? Or is a cube database different from an RDBMS, and if so how?
12
votes
5answers
3k views

Is ROLLBACK a fast operation?

Is it true that RDBMS systems are optimized for COMMIT operations? How much slower/faster are ROLLBACK operations and why?
4
votes
0answers
162 views

Which SQL datatypes exist since when and in which RDBMS? [closed]

I found a general comparision of different SQL implementations that only covers some data types (BOOLEAN and TIMESTAMP) and a comparision of datat type support in different RDBMS from 2009 that does ...
3
votes
1answer
1k views

How mature is the Firebird database when compared with PostgreSQL and MySQL?

I have used PostgreSQL with small projects and MySQL is running in production environment. No issues with them. I have been hearing of Firebird which is again a solid RDBMS in the open-source area. ...
4
votes
3answers
672 views

MySQL very slow query when changing one WHERE field despite no index/key

This is quite a confusing issue for me. I have a database full of baseball statistics. Running this query: SELECT * FROM hits JOIN stadiums ON stadiums.gameName = hits.gameName JOIN players ON ...
3
votes
1answer
2k views

Amazon SimpleDB or Amazon RDS?

I'm at a deciding point in my project of whether to implement the database using SimpleDB or Amazon RDS. The database needs to be accessed through an iPhone app and as well through a website. Here are ...
7
votes
1answer
204 views

Are relations slower than a big, inefficient table?

I've been asked in my job to violate the first normal form (repeating groups across columns, using empty / null values) several times, "for the sake of computer processing power". In a nutshell, a ...
5
votes
4answers
2k views

Why are so many MPP solutions based on PostgreSQL instead of MySQL?

Astor Data, Greenplum and GridSQL all allow Massive Parallel Processing of SQL queries. They are also all built around PostgreSQL technology. Is this just because of licensing issues or are there ...
21
votes
4answers
3k views

What does “index” mean on RDBMSs? [closed]

I use indexes like most developpers do (mostly on... well ! index), but i'm sure there is a lot of subtle way to optimize a database using index. I'm not sure if it is specific to any implementation ...
50
votes
6answers
16k views

What are the differences between NoSQL and a traditional RDBMS?

What are the differences between NoSQL and a traditional RDBMS? Over the last few months, NoSQL has been frequently mentioned in the technical news. What are its most significant features relative to ...
5
votes
3answers
452 views

Which databases support parallel processing across multiple servers? [closed]

I need a database engine that can utilize multiple servers for processing a single SQL query in parallel. So far I know that this is possible with the some engines, though none of them are feasible ...