Database management systems (DBMSs) are specially designed applications that interact with the user, other applications, and the database itself to capture and analyze data.

learn more… | top users | synonyms

0
votes
2answers
109 views

Performance Benchmark - MySQL vs PostgreSQL [closed]

this is my first question here in DBA. I wish to do a performance comparison between MySQL and PostgreSQL using same database on the basis of total time taken to parse + execute + send result back ...
0
votes
1answer
36 views

Decompose Relation R(ABCDE) in 2nf and 3nf

Given relation R(ABCDE) with functional dependencies A->C B->D AB->E Given: AB is the primary key. I know that this relation is in 1NF because of partial dependencies A->C and B->D Now how I ...
0
votes
0answers
86 views

Difference between OID and Primary key

Although I understand basic difference that OID is external to the tuple and generated by the system and Primary key is inside the tuple and generated by the db designer, I want to understand why OID ...
1
vote
3answers
226 views

Does 3NF require 2NF?

I am a bit confused with the definition of 3NF. According to Wikipedia: The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E.F. Codd in ...
0
votes
1answer
351 views

What is the difference between covering and overlapping constraints use in DBMS?

What is the difference between covering and overlapping constraints use in DBMS?
0
votes
2answers
102 views

How to drop table with all reference to this table

I want to drop a table, and this table has be many table's foreign key. So I want to drop all those reference (just refernece, not other table) within the drop table process. Is there any simple ...
2
votes
3answers
339 views

What is the best way to store a lot of user-encrypted data?

I'm about to develop an application that will mainly store user-encrypted data. Each piece of data being encrypted thanks to an AES key, itself encrypted with the public RSA key of each granted user. ...
1
vote
2answers
154 views

Independent pairs of RAID 1 is superior to RAID 10 [closed]

I am rather new to databases. I was reading up on RAID Storage and it seems that the consensus is that RAID 10 is RAID 10 is best is terms of performance and redundancy However at the end ...
1
vote
1answer
60 views

Performing projection first and then selection?

Consider a simple query: Select username,usertype from Table1 Where usertype='Manager' Most probably the DBMS will be performing selection first, and then projection i.e. first pulling out rows ...
-4
votes
0answers
68 views

What does acid stand for in Database Management System? [closed]

I want to know about "acid" property in database management system. Can anyone explain me in brief?
0
votes
1answer
35 views

Access: search for more than one parameter?

I need to perform several queries, looking for more than one parameter. for example: in my field "lenght" I want to extract values matching both 4.6 and 4.7. then, next time I need 5.8 and 5.9, and ...
3
votes
2answers
563 views

FileWatcher Troubleshooting Options

I have setup a Credential/Procedure/Program/File Watcher/Job to monitor a folder for new files, but it is not working. I am trying to figure out what I can check to troubleshoot why this isn't ...