title: Zettelmarkup Key Type
role: manual
tags: #manual #meta #reference #zettel #zettelstore
syntax: zmk
back: 00001006030000 00001012931200
backward: 00001006030000 00001012931200
box-number: 1
copyright: (c) 2020-present by Detlef Stern <ds@zettelstore.de>
created: 20210212135017
forward: 00001006033500 00001007000000
lang: en
license: EUPL-1.2-or-later
modified: 20230419175441
published: 20230419175441
visibility: public

Values of this type are [[String|00001006033500]] values, interpreted as [[Zettelmarkup|00001007000000]].
=== Allowed values
All printable characters are allowed.
There must be at least one such character.
=== Query comparison
Comparison is done similar to the full-text search: both the value to compare and the metadata value are normalized according to Unicode NKFD, ignoring everything except letters and numbers.
Letters are mapped to the corresponding lower-case value.

For example, ""Brücke"" will be the prefix of ""(Bruckenpfeiler,"".
=== Sorting
To sort two values, the underlying encoding is used to determine which value is less than the other.

Uppercase letters are typically interpreted as less than their corresponding lowercase letters, i.e. ``A < a``.

Comparison is done character-wise by finding the first difference in the respective character sequence.
For example, ``abc > aBc``.