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111	111	=== The openMINDS schema template syntax ===
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114		-All openMINDS metadata models use a light-weighted schema template syntax for defining the expected metadata. The correspondingly formatted schema files use the extension: **##.schema.tpl.json##**.
	114	+All openMINDS metadata models are defined using a light-weighted schema template syntax. Although this schema template syntax is inspired by JSON-Schema, it outsources most schema technicalities to be handled in the openMINDS integration pipeline, making the openMINDS schemas more human-readable, especially for untrained eyes. The few remaining customized technical properties which need additional interpretation are prefixed in the syntax with **##"_"##**. Within the openMINDS integration pipeline (cf. below), the schema template syntax is interpreted, extended and flexibly translated to various formal metadata formats (e.g., JSON-Schema). The specifications of the openMINDS schema template syntax are described in following.
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117		-Although, as the file extension suggests, this openMINDS schema template syntax is inspired by JSON-Schema, it facilitates or even excludes technical aspects making the openMINDS schemas 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).
	117	+All openMINDS schemas need to have the extension **##.schema.tpl.json##** and each schema is defined as a nested associative array (dictionary) with the following conceptual structure:
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	119	+{{code language="json"}}
	120	+{
	121	+ "_type": "https://openminds.ebrains.eu/LABEL_OF_METADATA_MODEL/SCHEMA_NAME",
	122	+ "properties": {
	123	+ "PROPERTY_NAME": {
	124	+ "type": "DATA_TYPE",
	125	+ "_instruction": "METADATA_ENTRY_INSTRUCTION"
	126	+ },
	127	+ "required": [
	128	+ "PROPERTY_NAME"
	129	+ ]
	130	+}
	131	+{{/code}}
	132	+
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120		-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. 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.
	134	+**##"_type"##** defines the schema type (or namespace) with the depicted naming convention, where the label of the respective openMINDS metadata model (e.g., **##"core"##**) and the schema name (format: UpperCamelCase; e.g. **##"Person"##**) have to be specified. The schema name should be meaningful and provide some insides into what metadata content the schema covers.
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123		-For the more inexperienced programmers, let's start by explaining first some general terms that will be later used in the openMINDS schema template syntax specification. More experienced programmers can of course skip these explanations and jump directly further down to Specifications.
	137	+Under **##"properties"##** a nested associated array is defined, where each key defines the property name (format: lowerCamelCase; e.g. **##"givenName"##**) and the associated value is again a nested associated array defining the expected data **##"type"##** and the **##"_instructions"##** for entering the correct metadata for the respective property. Currently the openMINDS schema template syntax supports the following data types: **##"string, **##"integer"##**, **##"float"##**, **##"boolean"##**, **##"array"##** and **##"object"##**. Depending on the expected data type additional constraints can be made for the metadata entry of a respective property (cf. below).
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125		-**What are strings, integers, floats or booleans?** Generally speaking strings, integers, floats or booleans are derived **data types**. A **string** is defined as a sequence of characters between quotes (e.g., ##"Is this a string? YES!"## or ##'thisIsAlsoAString'##). For a string, openMINDS accepts Unicode characters. An **integer** is a whole number, positive or negative, without decimals, of unlimited length (e.g., ##5##, ##-5## or ##1238921234##). A **float** represents a real number, written with a decimal point dividing the integer and fractional part, both of unlimited length (e.g., ##5.15##, ##-5.15## or ##1238921234.1345##). A **boolean** represents a logical proposition by means of the binary digits ##0## (##false##) and ##1## (##true##), especially in computing and electronics. How a boolean is written depends highly on the format or computational language.
	139	+(% style="text-align: justify;" %)
	140	+Under **##"required"##** a list of property names can be provided that are obligatory to be present in a correctly instantiated metadata instance of the respective schema. If none of the properties are required, this key-value pair does not have to be specified.
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127		-**What is a list or array?** A **list** is a data structure that is a mutable ordered sequence of values (also called items). The values of a list are typically defined between square brackets (e.g., ##[value1, value2, value3]##). Note that the values within a list do not have to have the same data type. In contrast, an **array** is a data structure that is a mutable unordered sequence of values of the same data type. What data types are accepted for values in a list or in an array is highly depending on the format or computational language.
128		-
129		-**What is a key-value pair or an associative array?** A **key-value pair** (sometimes also called name-value pair, attribute-value pair, property-value pair, or field-value pair) is a basic data representation and standard language feature in computing languages, systems and applications. In most cases this concept is used to build an **associative array** (also called **dictionary**), meaning an unordered list of unique keys with associated values typically defined within curly brackets (e.g., ##{key1: value1, key3: value3, key2:value2}##). What data types are accepted for keys and values highly depends on the format or computational language. Note that a value could also be a data structure, such as a list, an array or an associative array.
130		-
131		-**What is JSON?** JSON is short for **J**ava**S**cript **O**bject **N**otation, a lightweight data-interchange format which is built on associative arrays with key-value pairs and lists. Each JSON document/file begins as associative array. The keys are separated from the values via a colon and key-value pairs are separated by a comma. While a key always has to be a string in double quotes, a value can be a string in double quotes, an integer, a float, a boolean (written as true or false), null, a list or an associative array. Nesting of these structures is unlimited. For more information please go to the official webpage: [[https:~~/~~/www.json.org/>>https://www.json.org/]]. Several serialisation formats have been built on the JSON specification, such as JSON-LD (cf.[[ Application details: JSON-LD - the openMINDS serialization format>>doc:Collabs.openminds.Documentation.Application details.WebHome||target="_blank"]]). In addition, several schema languages have been developed to annotate and validate JSON documents, such as JSON-Schema and SHACL (cf. The openMINDS integration pipeline).
132		-
133		-==== Specifications ====
134		-
135		-(coming soon)
136		-
137	137	=== The openMINDS integration pipeline ===
138	138
139	139	(//**coming soon**//) If you'd like to learn more about the openMINDS integration pipeline, especially if you'd like to contribute to it, please get in touch with us (the openMINDS development team) via the issues on the openMINDS or openMINDS_generator GitHub or the support email: openminds@ebrains.eu