Questions tagged [rdbms]

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

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71
votes
6answers
42k 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 ...
4
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3answers
1k 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 (...
7
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2answers
2k 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 ...
75
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5answers
35k views

Which database could handle storage of billions/trillions of records?

We are looking at developing a tool to capture and analyze netflow data, of which we gather tremendous amounts of. Each day we capture about ~1.4 billion flow records which would look like this in ...
31
votes
5answers
3k views

Is it OK to keep a value which updates in a table?

We are developing a platform for prepaid cards, which basically holds data about cards and their balance, payments, etc. Up until now we had a Card entity which has a collection of Account entity, ...
26
votes
3answers
22k views

Is it acceptable to have circular foreign key references\How to avoid them?

Is it acceptable to have a circular reference between two tables on the foreign key field? If not, how can these situations be avoided? If so, how can data be inserted? Below is an example of ...
4
votes
1answer
1k views

Optimizing indexes

I just began optimizing my schemas with indexes (pretty late I guess). I never dealt with huge dataset but I'll be soon coping with about 1 to 5 millions rows. Here is the schema I'm using right now ...
21
votes
4answers
5k 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 ...
8
votes
1answer
232 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 "...
6
votes
2answers
6k views

A database in MySQL is a schema in Oracle : I do not understand this statement

Please help me understand this statement: A database in MySQL is a schema in Oracle. I have just started to use Oracle and I find it different from other RDBMS softwares I have used like MSSQL, ...
6
votes
2answers
12k views

How to insert values in junction table for many to many relationships?

I have three tables in database: trips(trip_id(pk), trip_name(unique), user_id(fk)) places(place_id(pk), place_name(unique)) trips_places_asc(trip_id(fk), place_id(fk)) Since many trips can ...
3
votes
1answer
990 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; +-----+------+-------------+-----...
4
votes
1answer
282 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. ...
1
vote
1answer
446 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 ...
0
votes
1answer
36 views

Where MySQL is taking time either in disk read or computation? [closed]

From SQl case study System configuration is Software: Percona 5.6.15-63.0. Hardware: Supermicro; X8DTG-D; 48G of RAM; 24xIntel(R) Xeon(R) CPU L5639 @ 2.13GHz, 1xSSD drive (250G) Query is select ...