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Questions tagged [rdbms]

A relational database management system (RDBMS) is a database management system (DBMS) in which data is stored in tables and the relationships among the data are also stored in tables.

A relational database management system (RDBMS) is a database management system () that is based on the relational model as introduced by E. F. Codd, of IBM's San Jose Research Laboratory. Many popular databases that are currently in use are based on the relational database model.

RDBMSs have become a predominant choice for the storage of information in new databases used for financial records, manufacturing and logistical information, personnel data, and much more. Relational databases have often replaced legacy hierarchical databases and network databases because they are easier to understand and use. However, relational databases have been challenged by object databases, which were introduced in an attempt to address the object-relational impedance mismatch in relational database, and XML databases.

History:
The development for the RDBMS model began at in 1974
The first commercially available RDBMS system was in 1979
The first RDBMS system for Mac OS was in 1984

References:

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How to think in SQL?

How do I stop thinking every query in terms of cursors, procedures and functions and start using SQL as it should be? Do we make the transition to thinking in SQL just by practise or is there any magic to learning the set based query language? What…
msvcyc
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How to get the byte size of resultset in an SQL query?

Is it possible to get the size in bytes of the results of an sql query in MySQL? For example: select * from sometable; ths returns 10000 rows. I don't want the rows but the size of the resultset in bytes. Is it possible?
Raj
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Find longest matching ngrams in MySQL

Given a column containing ngrams in a VARCHAR with utf8mb4_unicode_ci collation: +---------------------------+ | ngram | +---------------------------+ | stack overflow | | stack | | overflow …
Arnaud Le Blanc
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Hadoop and Django, is it possible?

From what I understood, Hadoop is a distributed storage system thingy. However what I don't really get is, can we replace normal RDBMS(MySQL, Postgresql, Oracle) with Hadoop? Or is Hadoop is just another type of filesystem and we CAN run RDBMS on…
Haikal Nashuha
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Difference between time-series database and relational database

I have read some concept about time-series database and some answers about the differences between these 2 but I can't still get my head around these differences. How data is written and stored to disk that make the differences between time-series…
xtiger
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RMySQL dbWriteTable with field.types

I have a data frame, called df, that looks like this: dte, val 2012-01-01, 23.2323 2012-01-02, 34.343 The type on the columns is date and numeric. I would like to write this to a MySQL database using an already open connection. The connection…
Alex
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When to replace RDBMS/ORM with NoSQL

What kind of projects benefit from using a NoSQL database instead of rdbms wrapped by an ORM? Examples: Stackoverflow similiar sites? Social communities? forums?
jgauffin
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How universal is the LIMIT statement in SQL?

I'm in the process of generalizing a Django DB replication app and it uses the statement: SELECT %s FROM %s LIMIT 1 to fetch 1 row and use the Python DBAPI to describe the fields, it works fine with ORACLE and MySQL but, how cross platform is the…
Roberto Rosario
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How to store data with dynamic number of attributes in a database

I have a number of different objects with a varying number of attributes. Until now I have saved the data in XML files which easily allow for an ever changing number of attributes. But I am trying to move it to a database. What would be your…
Jörg
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How to design a movie database?

I'm trying to get my head round this mind boggling stuff they call Database Design without much success, so I'll try to illustrate my problem with an example. I am using MySQL and here is my question: Say I want to create a database to hold my DVD…
Keith Donegan
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SQL one to one relationship vs. single table

Consider a data structure such as the below where the user has a small number of fixed settings. User [Id] INT IDENTITY NOT NULL, [Name] NVARCHAR(MAX) NOT NULL, [Email] VNARCHAR(2034) NOT NULL UserSettings [SettingA], [SettingB], [SettingC] Is it…
Jamie
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How to retrieve all recursive children of parent row in Oracle SQL?

I've got a recursive query that's really stretching the limits of this Java monkey's SQL knowledge. Now that it's finally 1:30 in the AM, it's probably time to start looking for some help. This is one of the few times Google has failed me. The…
Will Lovett
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Why are RDBMS considered Available (CA) for CAP Theorem

If I understand the CAP Theorem correctly, availability means that the cluster continues to operate even if a node goes down. I've seen a lot of people (http://blog.nahurst.com/tag/guide) list RDBMS as CA, but I do not understand how RBDMS is…
PiedPiper
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MySQL Transactions and how does Rollback work?

I just came across Transactions and I wonder what are the pros and cons of using it, how does the rollback work, are the old values kept in memory, if bigger, what happens? For 1. I understand you have to use it for bank transfers, but would it…
loveNoHate
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Does MySQL/InnoDB implement true serializable isolation?

It is not entirely clear from MySQL documentation whether the InnoDB engine implements true serializable isolation1 or snapshot isolation, which is often confusingly called "serializable" too. Which one is it? If MySQL InnoDB doesn't, are there any…
Roman Starkov
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