Database Software

Interfaces (Languages/Protocols)
Networking
See: Networking technologies: accessing databases over the network.
SQL
PL/SQL
ODBC (“Open Database Connectivity”)
Types of databases/Terms
Relational
[#aciddb]: Atomicity, Consistency, Isolation, Durability (“ACID”)
Atomicity
Atomic (meaning that a series of changes can be made all at once; if there is an error making all of the changes than the portions which did not get updated can be reversed. Useful, for example, if certain fields need to be releated.)
Consistency
Isolation
When isolation is implemented, whenever data is being modified from one source, that data is marked as being in a state of being actively used. This way the data is not accessed until the modifications are complete. Specifically, isolation also enforces that database queries cannot access data which is marked as being used. An exception to isolation may be “dirty reading”.
Durability
Implementations
DBM
MySQL
PostGreSQL
[#firebird]: Firebird

Firebird is some database software released by the “Firebird Project” and which has a website at http://FirebirdSQL.org. This was initially based on Borland's InterBase 6 open source software.

A famous namespace clash occurred when another, more famous piece of software in the open source realm decided to adopt the name Firebird after Phoenix Technologies did not like Mozilla naming their upcoming (at the time) web browser Phoenix. However, specifically to cooperate with this already existing software project, this software was later named Mozilla Firebird temporarily before being renamed again to Mozilla Firefox.

Drizzle
http://en.wikipedia.org/wiki/Drizzle_%28database_server%29
[#oobase]: OpenAccess Base
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Interbase
Interbase is a commercial product, although there was a time when Borland released and worked on an open source version. From that open source version, Firebird was created.
Glom
Wikipedia's page on GNOME Office mentions that the software consists of, among other parts of that office suite, “Glom datbase designer, similar to FileMaker”.
Kexi
Part of the KOffice office suite (for KDE/Linux, and more recently also for Microsoft Windows and Mac OS X). Wikipedia's article on KOffice: Section labelled “Features” notes that Kexi is “designed as a Microsoft Access of FileMaker competitor”.
Microsoft SQL
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Oracle Database
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Microsoft Access
Microsoft has moved onto SQL-based solutions, although the software may still be used for working with some older databases.
Filemaker
Wikipedia's page on GNOME Office mentions that the software consists of, among other parts of that office suite, “Glom datbase designer, similar to FileMaker”. Wikipedia's article on KOffice: Section labelled “Features” notes that Kexi is “designed as a Microsoft Access of FileMaker competitor”.
IBM DB2
xBase
Wikipedia's article on dBase states that dBase, “FoxPro, Paradox, and Clipper/Harbour, together informally referred to as xBase.”
Misc/unsorted