Changes for page Technical details

Last modified by lzehl on 2021/07/05 18:57

From 16.1 to 15.1 From 41.1 to 40.1

From version 40.1

edited by lzehl
on 2021/03/09 16:52

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To version 16.1

edited by lzehl
on 2021/03/08 20:14

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@@ -18,137 +18,52 @@
  === The openMINDS schema template syntax ===
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--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##**.
++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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--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).
++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.
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--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.
++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.
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--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.
++===== Target & context templates =====
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--===== Target & concept templates =====
++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:
--(% style="text-align: justify;" %)
--Same as in JSON-Schema, all openMINDS schema templates define the expected name (written in **##lowerCamelCase##**) and value of the metadata, typically called property, under the key **##properties##** as nested dictionaries. Furthermore, the names of obligatory metadata can be listed under the key **##required##**. Here a generalized example:
++(% style="text-align: center;" %)
++**##"_type": "https:~/~/openminds.ebrains.eu/<<schema-model>>/<<schema-name>>"##**,
--{{code language="json"}}
--{
-- "properties": {
--   "propertyNameA": {},
--   "propertyNameB": {},
--   "propertyNameC": {}
-- },
-- "required": [
--   "propertyNameA",
--   "propertyNameC"
-- ]
--}
--{{/code}}
--
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--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. Here again a generalized example:
++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.
--{{code language="json"}}
--{
-- "_type": "https:~/~/openminds.ebrains.eu/<<schema-model>>/<<schema-name>>",
-- "properties": {}
--}
--{{/code}}
--
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--Note that **##<<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 the schema (written in **##CamelCase##**).
++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.
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--If an openMINDS schema template //does not// define a key **##"_type"##** (as in the first example above), it is interpreted as a **concept template** which //has to be// extended to 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.
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--Concept templates are and should be used when multiple target templates have the same subset of properties, because they facilitate the long-term maintenance of those shared properties: Instead of defining the same properties repeatedly within multiple target templates, the common subset can be defined within a single concept template and passed on to all extending target templates.
++===== String properties =====
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--To define that a target template is the extension of a concept template, the target template can state under **##"_extends"##** the relative path to the concept template. For example, the openMINDS core target template **##Dataset##** extends the core concept template **##researchProduct##** as indicated here:
++(//**coming soon**//)
--{{code language="json"}}
--{
--  "_type": "https:~/~/openminds.ebrains.eu/core/Dataset",
--  "_extends": "products/researchProduct.schema.tpl.json"
--}
--{{/code}}
--
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--Note that this convention requires the concept and corresponding target templates to be located in the same openMINDS metadata model repository. Note also that for properties, the following rules apply for target and concept template:
++===== Numerical properties =====
--1. A concept template has to define some properties which will be inherited by all extending target templates.
--1. If a concept template additionally states that some of these properties are required, all extending target templates will require the same properties.
--1. A target template can require properties of the concept template, that are not explicitly required within the concept template. In such a case, the other target templates extending the same concept template will not require those properties.
--1. A target template can (but does not have to) define and require additional properties that were not defined and required in the concept template. These additionally defined and required properties will not be shared with the other target templates extending the same concept template.
--
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--How to define the expected value of a property will be explained for the different property types in the following sections.
--
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--===== Properties expecting a string value =====
--
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--Properties that expect values of type string can be defined in large parts in the same way as in JSON-Schema. Without any further formatting requirements the definition of such a property looks like this:
--
--{{code language="json"}}
--{
--  "properties": {
--    "freeStringProperty": {
--      "type": "string"
--    }
--  }
--}
--{{/code}}
--
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--In accordance with JSON-Schema, it is possible, though, to further define a selected list of built-in formats that are accepted for the expected string. Supported are all [[built-in formats of JSON-Schema Draft 7.0>>https://json-schema.org/understanding-json-schema/reference/string.html#built-in-formats||rel="noopener noreferrer" target="_blank"]]. Assuming that my string property only accepts a value of format "email", the openMINDS syntax is the following:
--
--{{code language="json"}}
--{
--  "properties": {
--    "emailProperty": {
--      "type": "string",
--      "_formats": [
--        "email"
--      ]
--    }
--  }
--}
--{{/code}}
--
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--Also like JSON-Schema, it is possible to define a customized regular expression pattern for the expected string, supporting the [[ECMA-262  regex-dialect>>https://www.ecma-international.org/publications-and-standards/standards/ecma-262/]]. Assuming that my string property only accepts a Gregorian calendar year, the corresponding openMINDS syntax look like this:
--
--{{code language="json"}}
--{
--  "properties": {
--    "yearProperty": {
--      "type": "string",
--      "pattern": "([0-9]{4})"
--    }
--  }
--}
--{{/code}}
--
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--===== Properties expecting a numerical value =====
--
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  (//**coming soon**//)
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--===== Properties expecting another object =====
++===== Object properties =====
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  (//**coming soon**//)
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--===== Properties expecting an array of values =====
++===== Property arrays =====
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  (//**coming soon**//)