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21	21	All openMINDS metadata models use a light-weighted schema template syntax for defining the metadata. The correspondingly formatted schema files use the extension: **##.schema.tpl.json##**.
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24		-Although, as the file extension suggests, this openMINDS schema template syntax is inspired by JSON-Schema, it facilitates or even excludes technical aspects that are generally expected for the openMINDS schemas making it more human-readable, especially for untrained eyes.
	24	+Although, as the file extension suggests, this openMINDS schema template syntax is inspired by JSON-Schema, it facilitates or even excludes technical aspects that are generally expected for the openMINDS schemas making them more human-readable, especially for untrained eyes. Behind the scenes, within the openMINDS integration pipeline (cf. below), this schema template syntax is then interpreted and flexibly translated to various formal metadata formats (e.g., JSON-Schema).
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27		-Behind the scenes, within the openMINDS integration pipeline (cf. below), this schema template syntax is then interpreted and flexibly translated to various formal metadata formats (e.g., JSON-Schema). Please find in the following a full documentation of the openMINDS schema template syntax and how it needs to be interpreted.
	27	+Despite the simplification in comparison to JSON-Schema, the openMINDS schema templates are also, at the core, specially formatted JSON files using a particular syntax, meaning special key-value pairs that define the validation rules of a schema.
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	30	+Please find in the following a full documentation of the openMINDS schema template syntax and how it's key-value pairs need to be defined and interpreted.
	31	+
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30	30	===== Target & context templates =====
31	31
32		-All openMINDS schemas have to have a **##"_type"##** to be recognized as target templates. In other words, the **##"_type"##** is used to define the openMINDS namespace of a corresponding schema using the following naming convention:
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	36	+Same as in JSON-Schema, all openMINDS schemas define the name and value of the metadata they expect under the key **##properties##** as nested dictionaries, and which of those properties is obligatory under the key **##required##** listing the corresponding property names, as depicted here:
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35		-**##"_type": "https:~/~/openminds.ebrains.eu/<<schema-model>>/<<schema-name>>"##**,
	38	+{{code language="json"}}
	39	+{
	40	+ "properties": {
	41	+ "propertyNameA": {},
	42	+ "propertyNameB": {},
	43	+ "propertyNameC": {}
	44	+ },
	45	+ "required": [
	46	+ "propertyNameA",
	47	+ "propertyNameC"
	48	+ ]
	49	+}
	50	+{{/code}}
36	36
37		-where **##<<schema-model>>##** has to be replaced with the label of the openMINDS metadata model the corresponding schema belongs to and **##<<schema-name>>##** exchanged with the label of that schema.
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	53	+In addition, an openMINDS schema //has to have// a key **##"_type"##** to be recognized as **target template**. In other words, the **##"_type"##** is used to define the openMINDS namespace of a corresponding schema using a particular naming convention, as depicted here:
38	38
39		-If an openMINDS schema template file does not define a **##"_type"##**, it is interpreted as a context template which requires an extension to become a target template. Context templates are and should be used when multiple openMINDS schemas (target templates) have the same subset of properties. This common subset of properties can then be defined within a single context schema instead of each target template which facilitates the long-term maintenance of these properties.
	55	+{{code language="json"}}
	56	+{
	57	+ "_type": "https:~/~/openminds.ebrains.eu/<<schema-model>>/<<schema-name>>",
	58	+ "properties": {},
	59	+ "required": []
	60	+}
	61	+{{/code}}
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	64	+where **##<<schema-model>>##** has to be replaced with the label of the openMINDS metadata model to which the corresponding schema belongs to, and **##<<schema-name>>##** has to be replaced with the corresponding name of that schema (written in **##CamelCase##**).
	65	+
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	67	+If an openMINDS schema template //does not// define a key **##"_type"##** (as in the first example above), it is interpreted as a **context template** which //has to be// extended to a target template.
	68	+
	69	+(% style="text-align: justify;" %)
	70	+Context templates are and should be used when multiple openMINDS schemas (target templates) have the same subset of properties. Such a common subset of properties can then be defined within a single context schema instead of each target template which facilitates the long-term maintenance of these properties.
	71	+
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	73	+To define that a target template is the extension of a context template, the target template can state under **##"_extends"##** the relative path to the context template. For example, the openMINDS core target template **##Dataset##** extends the core concept template **##researchProduct##**:
	74	+
	75	+{{code language="json"}}
	76	+{
	77	+ "_type": "https:~/~/openminds.ebrains.eu/core/Dataset",
	78	+ "_extends": "products/researchProduct.schema.tpl.json",
	79	+ "properties": []
	80	+}
	81	+{{/code}}
	82	+
	83	+Note that this convention requires the context and corresponding target templates to be located in the same openMINDS metadata model repository. Note also that both, target and concept template, can or cannot define required properties. In this context, the following rules apply:
	84	+
	85	+1. If a concept template requires properties, the target templates extending this concept template require the same properties.
	86	+1. A target template can require properties of the concept template, that are not explicitly required within the concept template. Other target templates extending the same concept template will not require those properties.
	87	+1. A target template can define and require additional properties that were not defined and required in the concept template. These properties are not shared with the other target templates that extend the same concept template.
	88	+
	89	+How to define the expected value of a property will be explained for the different property types in the following sections.
	90	+
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42	42	===== String properties =====
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