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Last modified by lzehl on 2021/07/05 18:57
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... ... @@ -111,34 +111,29 @@ 111 111 === The openMINDS schema template syntax === 112 112 113 113 (% style="text-align: justify;" %) 114 -All openMINDS metadata models are definedusinga light-weighted schema template syntax.Although this schema template syntax is inspiredby JSON-Schema, it outsources most schema technicalities to be handledinthe openMINDSintegrationpipeline, makingtheopenMINDS schemasmorehuman-readable, especially for untrained eyes. Thefew remainingcustomized technical propertieswhich need additional interpretationare prefixedthe syntaxwith **##"_"##**. Within theopenMINDS integration pipeline (cf. below),the schematemplate syntax is interpreted, extended andflexibly translatedto variousformal metadataformats (e.g., JSON-Schema).Thespecificationsf the openMINDSschemaemplatesyntax are described in following.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##**. 115 115 116 116 (% style="text-align: justify;" %) 117 -All openMINDS schemas ne edtohave the extension**##.schema.tpl.json##**andeachschemais definedasa nestedassociativearray(dictionary)withthefollowingconceptual structure: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). 118 118 119 -{{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 - 133 133 (% style="text-align: justify;" %) 134 - **##"_type"##** definesthe schema type (or namespace) with the depictednamingconvention,wherethelabeloftherespectiveopenMINDSmetadatamodel(e.g.,**##"core"##**)andtheschemaname(format:UpperCamelCase;e.g. **##"Person"##**)havetobespecified.The schemanameshouldbemeaningful andprovidesomeinsidesinto whatmetadatacontenttheschemacovers.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. 135 135 136 136 (% style="text-align: justify;" %) 137 - Under **##"properties"##**a nestedassociatedarrayis defined, whereeach keydefinestheproperty name (format: lowerCamelCase;e.g. **##"givenName"##**) andthe associatedvalue isagain a nestedassociatedarraydefiningthe expected data **##"type"##** and the **##"_instructions"##**forenteringthecorrectmetadatafortherespectiveproperty.Currentlythe openMINDS schema template syntax supports theollowing data types: **##"string,**##"integer"##**, **##"float"##**, **##"boolean"##**,**##"array"##**and**##"object"##**.Dependingonthe expected dataype additional constraintscanbemade formetadata entryofa respective property (cf.below).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. 138 138 139 -(% 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. 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. 141 141 127 +**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 + 142 142 === The openMINDS integration pipeline === 143 143 144 144 (//**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