Good reasons NOT to use a relational database?

Question

Can you please point to alternative data storage tools and give good reasons to use them instead of good-old relational databases? In my opinion, most applications rarely us

Answer 1

Also: * Embedded scenarios - Where usually it is required to use something smaller then a full fledged RDBMS. Db4o is an ODB that can be easily used in such case. * Rapid or proof-of-concept development - where you wish to focus on the business and not worry about persistence layer

Answer 2

There was a RAD tool called JADE written a few years ago that has a built-in OODBMS. Earlier incarnations of the DB engine also supported Digitalk Smalltalk. If you want to sample application building using a non-RDBMS paradigm this might be a start.

Other OODBMS products include Objectivity, GemStone (You will need to get VisualWorks Smalltalk to run the Smalltalk version but there is also a java version). There were also some open-source research projects in this space - EXODUS and its descendent SHORE come to mind.

Sadly, the concept seemed to die a death, probably due to the lack of a clearly visible standard and relatively poor ad-hoc query capability relative to SQL-based RDMBS systems.

An OODBMS is most suitable for applications with core data structures that are best represented as a graph of interconnected nodes. I used to say that the quintessential OODBMS application was a Multi-User Dungeon (MUD) where rooms would contain players' avatars and other objects.

Answer 3

K.I.S.S: Keep It Small and Simple

Answer 4

The filesystem's prety handy for storing binary data, which never works amazingly well in relational databases.

Answer 5

One might want to consider the use of an LDAP server in the place of a traditional SQL database if the application data is heavily key/value oriented and hierarchical in nature.

Answer 6

Plain text files in a filesystem

• Very simple to create and edit
• Easy for users to manipulate with simple tools (i.e. text editors, grep etc)
• Efficient storage of binary documents

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XML or JSON files on disk

• As above, but with a bit more ability to validate the structure.

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Spreadsheet / CSV file

• Very easy model for business users to understand

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Subversion (or similar disk based version control system)

• Very good support for versioning of data

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Berkeley DB (Basically, a disk based hashtable)

• Very simple conceptually (just un-typed key/value)
• Quite fast
• No administration overhead
• Supports transactions I believe

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Amazon's Simple DB

• Much like Berkeley DB I believe, but hosted

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Google's App Engine Datastore

• Hosted and highly scalable
• Per document key-value storage (i.e. flexible data model)

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CouchDB

• Document focus
• Simple storage of semi-structured / document based data

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Native language collections (stored in memory or serialised on disk)

• Very tight language integration

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Custom (hand-written) storage engine

• Potentially very high performance in required uses cases

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I can't claim to know anything much about them, but you might also like to look into object database systems.