fix: style names and prettier ignore for grid tables in cim 009

## A.1 Introduction

The purpose of identifiers is to allow uniquely identifying NGSI-LD elements (Entities, Context Subscriptions or [Context Source Registrations]{.HTML_Keyboard}) within an NGSI-LD system. This annex is intended to clarify the different issues around the design of identifiers in NGSI-LD.

The purpose of identifiers is to allow uniquely identifying NGSI-LD elements (Entities, Context Subscriptions or [Context Source Registrations]{.HTML-Keyboard}) within an NGSI-LD system. This annex is intended to clarify the different issues around the design of identifiers in NGSI-LD.

## A.2 Entity identifiers

In order to enable the participation of NGSI-LD in linked data scenarios, all Entities are identified by **URIs**. If those URIs are expected to participate in external linked data relationships they **should** be dereferenceable.

It is noteworthy that the identifier from the point of view of NGSI-LD is different from the inherent identifier that a specific Entity may have. For instance, an NGSI-LD Entity of Type ["Vehicle"]{.HTML_Code} may have a Property named *licencePlateNumber*, which it is actually a unique identifier from the point of view of the Entity domain, as it uniquely identifies the specific vehicle instance. However, from the point of view of the NGSI-LD system, it may have another identifier which might or might not include such licence plate number identifier.

It is noteworthy that the identifier from the point of view of NGSI-LD is different from the inherent identifier that a specific Entity may have. For instance, an NGSI-LD Entity of Type ["Vehicle"]{.HTML-Code} may have a Property named [licencePlateNumber]{.HTML-Variable}, which it is actually a unique identifier from the point of view of the Entity domain, as it uniquely identifies the specific vehicle instance. However, from the point of view of the NGSI-LD system, it may have another identifier which might or might not include such licence plate number identifier.

## A.3 NGSI-LD namespace

The referred namespace is defined as follows (to be registered with IANA):

- namespace identifier: NID = ["ngsi-ld"]{.HTML_Code}

- namespace specific string: NSS = EntityTypeName [":"]{.HTML_Code} EntityIdentificationString

- namespace identifier: NID = ["ngsi-ld"]{.HTML-Code}

- namespace specific string: NSS = EntityTypeName [":"]{.HTML-Code} EntityIdentificationString

*EntityTypeName* shall be an Entity Type name which can be expanded to a URI as per the *\@context*.

EntityTypeName shall be an Entity Type name which can be expanded to a URI as per the [\@context]{.HTML-Variable}.

*EntityIdentificationString* shall be a string that allows uniquely identifying the subject Entity in combination with the other items being part of the NSS.

EntityIdentificationString shall be a string that allows uniquely identifying the subject Entity in combination with the other items being part of the NSS.

>>> [!tip] EXAMPLE:

[urn:ngsi-ld:Person:28976543]{.HTML_Code} .

[urn:ngsi-ld:Person:28976543]{.HTML-Code} .

>>>

It is recommended that applications use this URN namespace when applicable.

In general, the URN specification defines namespace equivalence in a case-insensitive manner, however it is assumed that context-broker implementations shall always use lowercase letters in namespaces where they have a choice in case, unless there is a strong reason otherwise. Restricting the namespace prefix to lower case [urn:ngsi-ld:]{.HTML_Code} can improve caching and retrieval, since this ensures since alphabetic characters within the namespace specific string are always consistent.

In general, the URN specification defines namespace equivalence in a case-insensitive manner, however it is assumed that context-broker implementations shall always use lowercase letters in namespaces where they have a choice in case, unless there is a strong reason otherwise. Restricting the namespace prefix to lower case [urn:ngsi-ld:]{.HTML-Code} can improve caching and retrieval, since this ensures since alphabetic characters within the namespace specific string are always consistent.

# Annex B (normative): Core NGSI-LD \@context definition

Below is the definition of the Core NGSI-LD *\@context* which shall be supported by implementations.

Below is the definition of the Core NGSI-LD [\@context]{.HTML-Variable} which shall be supported by implementations.

Such definition has been tested using [i.7].

>>> [!note] NOTE:

Implementers can take advantage of prefixed terms, i.e. in the form ngsi-ld:term, to provide a terser representation of the Core *\@context* .

Implementers can take advantage of prefixed terms, i.e. in the form ngsi-ld:term, to provide a terser representation of the Core [\@context]{.HTML-Variable} .

>>>

## D.2 Algorithm for transforming an NGSI-LD Entity into a JSON-LD document (ALG1)

This algorithm takes as input an NGSI-LD graph which top level node is a particular Entity and returns as output a JSON-LD document which represents all the data associated to the entity. The JSON-LD document (and its associated *\@context*) corresponds to a representation of the Entity in JSON-LD as per the NGSI-LD Information Model.

This algorithm takes as input an NGSI-LD graph which top level node is a particular Entity and returns as output a JSON-LD document which represents all the data associated to the entity. The JSON-LD document (and its associated [\@context]{.HTML-Variable}) corresponds to a representation of the Entity in JSON-LD as per the NGSI-LD Information Model.

>>> [!note] NOTE:

- **O** be a JSON object initialized to the empty object ({}).

- **C** be a JSON-LD *\@context* initialized as described by annex B.

- **C** be a JSON-LD [\@context]{.HTML-Variable} initialized as described by annex B.

The algorithm should run as follows, provided all the preconditions defined above are satisfied:

3.  For each Property Psi (Pi, "AliasP", Vi, Di) associated to N:

    a.  Run Algorithm*ALG1.1*

    a.  Run Algorithm ALG1.1 taking the following inputs:

        - Ps → Psi.

        - O → O.

        - C → C.

4.  For each Relationship Rs (Ri, AliasRi, Robji) associated to N:

    a.  Run Algorithm*ALG1.2*

    a.  Run Algorithm ALG1.2 taking the following inputs:

        - Rs → Rsi.

        - O → O.

        - C → C.

    a.  For each Property associated to Ps (Pss) recursively run the present algorithm (*ALG1.1*

    a.  For each Property associated to Ps (Pss) recursively run the present algorithm (ALG1.1) taking the following inputs:

        - Ps → Pss.

        - O → Op.

        - C → C.

    a.  For each Relationship associated to Ps (Rss) run algorithm*ALG1.2*

    a.  For each Relationship associated to Ps (Rss) run algorithm ALG1.2 taking the following inputs:

        - Rs → Rss.

        - O → Op.

        - C → C.

    a.  For each Property associated to Rs (Pss) run the algorithm*ALG1.1*

    a.  For each Property associated to Rs (Pss) run the algorithm ALG1.1 taking the following inputs:

        - Ps → Pss.

        - O → Or.

        - C → C.

    a.  For each Relationship associated to Rs (Rss) recursively run the present algorithm*ALG1.2*

    a.  For each Relationship associated to Rs (Rss) recursively run the present algorithm ALG1.2 taking the following inputs:

        - Rs → Rss.

        - O → Or.

        - C → C.

>>> [!tip] EXAMPLE 1:

**NGSI-LD Linked Entity** , [Linked Entity]{.HTML_Keyboard} .

**NGSI-LD Linked Entity** , [Linked Entity]{.HTML-Keyboard} .

>>>

>>> [!tip] EXAMPLE 2:

*options* .

[options]{.HTML-Variable} .

>>>

>>> [!tip] EXAMPLE 4:

*createdAt* , *value* , *unitCode* .

[createdAt]{.HTML-Variable} , [value]{.HTML-Variable} , [unitCode]{.HTML-Variable} .

>>>

>>> [!tip] EXAMPLE 5:

*ListRelationship, GeoProperty, Geometry, Second, Number* .

[ListRelationship, GeoProperty, Geometry, Second, Number]{.HTML-Definition} .

>>>

>>> [!tip] EXAMPLE 6:

["application/json"]{.HTML_Code} , ["Subscription"]{.HTML_Code} .

["application/json"]{.HTML-Code} , ["Subscription"]{.HTML-Code} .

>>>

When referring to the JSON-LD Context the mnemonic text string *\@context* is used as a placeholder.

When referring to the JSON-LD Context the mnemonic text string [\@context]{.HTML-Variable} is used as a placeholder.

All the dates and times are given in UTC format.

>>> [!tip] EXAMPLE 7:

[2018-02-09T11:00:00Z]{.HTML_Code} .

[2018-02-09T11:00:00Z]{.HTML-Code} .

>>>