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| author | alex <alex@pdp7.net> | 2026-03-01 18:03:58 +0100 |
|---|---|---|
| committer | alex <alex@pdp7.net> | 2026-03-01 18:03:58 +0100 |
| commit | 106dd7d4967bf42831624f9a06a6fb25213b86c7 (patch) | |
| tree | 4cae8bdabfb00f32a2672605b5572f74c36f630e /programming | |
| parent | 4d02fd0cca0991657f7b77364d8399c384d2f38a (diff) | |
Move about relational databases to blog website
Diffstat (limited to 'programming')
| -rw-r--r-- | programming/about_relational_databases.md | 30 |
1 files changed, 0 insertions, 30 deletions
diff --git a/programming/about_relational_databases.md b/programming/about_relational_databases.md deleted file mode 100644 index 464de330..00000000 --- a/programming/about_relational_databases.md +++ /dev/null @@ -1,30 +0,0 @@ -# About relational databases - -## What is a relation? - -A common misconception is that the "relations" in a relational database are about relations between database tables. - -Actually, the relations in a relational database are the tables. - -A relation "relates" a set of values with another set of values. - -For example, a relation can relate the name of a person with their birth date and birth place. -For example: - -``` -(person name) => (birth date, birth place) -(Alice) => (1979-12-03, Barcelona) -(Bob) => (1995-03-04, Paris) -... -``` - -Many computer languages have similar concepts: - -* [Python mapping types such as `dict`](https://docs.python.org/3/library/stdtypes.html#mapping-types-dict) -* C++ `std::map` -* Java `java.util.Map` -* [C# `System.Collections.Generic.Dictionary`](https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2?view=net-9.0) -* [Javascript `Object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) -* [PHP arrays](https://www.php.net/manual/en/language.types.array.php) - -Relations are a natural concept, so although non-relational data systems exist, most data can be stored as relations. |