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5.1.1Array Properties

Array properties hold an array of one or more objects, which are usuallydescription objects.

For example, thetables property is an array property. Atable group description might contain:

"tables": [{  "url": "https://example.org/countries.csv",  "tableSchema": "https://example.org/countries.json"}, {  "url": "https://example.org/country_slice.csv",  "tableSchema": "https://example.org/country_slice.json"}]

in which case thetables property has a value that is an array of twotable description objects.

Any items within an array that are not valid objects of the type expected are ignored. If the supplied value of an array property is not an array (e.g. if it is an integer), compliant applicationsMUST issue a warning and proceed as if the property had been supplied with an empty array.

5.1.2Link Properties

Link properties hold a single reference to another resource by URL. Their value is astring — resolved as a URL against thebase URL. If the supplied value of a link property is not a string (e.g. if it is an integer), compliant applicationsMUST issue a warning and proceed as if the property had been supplied with an empty string.

For example, theurl property is a link property. Atable description might contain:

"url":"example-2014-01-03.csv"

in which case theurl property on the table would have a single value, a link toexample-2014-01-03.csv, resolved against thebase URL of the metadata document in which this was located. For example if the metadata document contained:

"@context":["http://www.w3.org/ns/csvw",{"@base":"http://example.org/"}]

this is equivalent to specifying:

"url":"http://example.org/example-2014-01-03.csv"

5.1.3URI Template Properties

URI template properties contain a [URI-TEMPLATE] which can be used to generate a URI. These URI templates are expanded in the context of each row by combining the template with a set of variables with values as defined in [URI-TEMPLATE]. The following variables are set:

column names

a variable is set for each column within theschema; the name of the variable is thecolumn name of thecolumn from theannotated table and the value is derived from thevalue of the cell in that column in the row that is currently being processed, namely one of:

• null,
• thecanonical representation of the value of the cell, based on its datatype as defined in [xmlschema11-2], if it has a single value, or
• a list ofcanonical representations of the values of the cell, if it has a sequence value.

Note

The languages ofcell values are ignored.

_column

_column is set to thecolumn number of thecolumn from theannotated table that is currently being processed.

_sourceColumn

_sourceColumn is set to thesource number of the column that is currently being processed; this usually varies from_column byskip columns.

_row

_row is set to therow number of therow from theannotated table that is currently being processed.

_sourceRow

_sourceRow is set to thesource number of the row that is currently being processed; this usually varies from_row byskip rows andheader rows.

_name

_name is set to the URI decodedcolumn name annotation, as defined in [tabular-data-model], for the column that is currently being processed. (Percent-decoding is necessary asname may have been encoded if taken fromtitles; this prevents double percent-encoding.)

Theannotation value is the result of:

1. applying the template against the cell in that column in the row that is currently being processed.
2. expanding anyprefixes as if the value were the name of acommon property, as described insection5.8Common Properties.
3. resolving the resulting URL against the base URL of thetable url if not null.

If the supplied value of a URI template property is not a string (e.g. if it is an integer), compliant applicationsMUST issue a warning and proceed as if the property had been supplied with an empty string.

For example, theaboutUrl property holds a URI template that is used to generate a URL identifier for each row, which might look like:

"aboutUrl":"http://example.org/example.csv#row.{_row}"

Theabout URL annotations that are generated and used as identifiers for the rows would then look likehttp://example.org/example.csv#row.1,http://example.org/example.csv#row.2 and so on.

Alternatively, with the CSV and metadata in thesection1.Introduction, theaboutUrl might look like:

"aboutUrl":"http://example.org/tree/{on_street}/{GID}"

This would generate URIs such ashttp://example.org/tree/ADDISON%20AV/1 andhttp://example.org/tree/EMERSON%20ST/2.

If the value of theon_street orGID column werenull, the URL would still be generated with the null value generating an empty string in the URL. For example ifon_street werenull andGID were3, the generated URL would behttp://example.org/tree//3.

Once the URI has been generated, it is resolved against the url of the table (e.g. the CSV file) to create an absolute URI. For example, given aaboutUrl within a schema such as:

"aboutUrl":"#row.{_row}"

and given a CSV file athttp://example.com/temp.csv, the URL for the first row will behttp://example.com/temp.csv#row.1.

ThepropertyUrl property might be defined as"{#_name}", meaning that it resolves as a fragment identifier relative to the URL of the source of the table. For example, accessing it from a column with the column nameGID would look like:

"http://example.org/example.csv#GID"

A value defined within the data is also subject to expansion. For example, consider the following table:

project_name,project_type,keywordsCSVW,foaf:Project,table;data;conversion

Theproject_type column might have avalueUrl specified as"{project_type}". In the first row the cell value is"foaf:Project". Thefoaf prefix is understood, as described insection5.8Common Properties, to expand tohttp://xmlns.com/foaf/0.1/Project.

Similarly, thekeywords column might have avalueUrl specified as"https://duckduckgo.com/?q={keywords}". If the column also specifies"separator": ";", then the cell value of thekeywords column would be an array of the three valuestable,data, andconversion. This is set as the value of thekeywords variable within the URI template, which means the result would behttps://duckduckgo.com/?q=table,data,conversion.

If the value in thekeywords column were an empty sequence (created from an empty cell in the original data), the reference to that column would be expanded to an empty string, generatinghttps://duckduckgo.com/?q=.

When a cell'svalue is not a string, the canonical representation of that value is used within the expanded URL. For example, the data may include dates such as those in:

GID,On Street,Species,Trim Cycle,Inventory Date1,ADDISON AV,Celtis australis,Large Tree Routine Prune,10/18/20102,EMERSON ST,Liquidambar styraciflua,Large Tree Routine Prune,6/2/2010

TheInventory Date column description would indicate that these were dates with the formatM/d/yyyy:

{"name":"inventory_date","titles":"Inventory Date","datatype":{"base":"date","format":"M/d/yyyy"}}

The string value of theinventory_date column in the first row is parsed to create the date 18th October 2010. When theinventory_date column is referenced within a URI template such ashttp://example.org/event/{inventory_date}, thecanonical representation of that date, as defined in [xmlschema11-2] is used within the URL, giving the resulthttp://example.org/event/2010-10-18.

5.1.4Column Reference Properties

Column reference properties hold one or more references to othercolumn description objects. The referenced description object must have aname property. Column reference properties can then reference column description objects through values that are:

• strings — whichMUST match thename on acolumn description object within the metadata document.
• arrays — lists of strings as above.

Compliant applicationsMUST issue a warning and proceed as if the column reference property had not been specified if:

• the supplied value is not a string or array (e.g. if it is an integer).
• the supplied value is an empty array.
• any of the values in the supplied array are not strings.
• any of the supplied strings do not reference one or more columns.

For example, theprimaryKey property is a column reference property on the schema. It has to hold references to columns defined elsewhere in the schema, and the descriptions of those columns must havename properties. It can hold a single reference, like this:

"tableSchema":{"columns":[{"name":"GID"},...],"primaryKey":"GID"}

or it can contain an array of references, like this:

"tableSchema":{"columns":[{"name":"givenName"},{"name":"familyName"},...],"primaryKey":["givenName","familyName"]}

If theprimaryKey property were given an invalid value, such as1, or a column name were misspelled, the processorMUST issue a warning and ignore the value.

On the other hand, thecolumnReference property is a required property; if it has an invalid value, such as an empty array, then the processor will issue an error as if the property were not specified at all.

5.1.5Object Properties

Object properties hold either a single object or a reference to an object by URL. Their values may be:

• strings — resolved as URLs against thebase URL.
• objects — interpreted as structured objects.

If the supplied value of an object property is not a string or object (e.g. if it is an integer), compliant applicationsMUST issue a warning and proceed as if the property had been specified as an object with no properties.

Object properties are often used when the values can be or should be values within controlled vocabularies, or structured information which may be held elsewhere. For example, thedialect of a table is an object property. It could be provided as a URL that indicates a commonly used dialect, like this:

"dialect":"http://example.org/tab-separated-values"

or a structured object, like this:

"dialect":{"delimiter":"\t","encoding":"utf-8"}

When specified as a string, the resolved URL is used to fetch the referenced object duringnormalization as described insection6.Normalization. For example, ifhttp://example.org/tab-separated-values resolved to:

{"@context":"http://www.w3.org/ns/csvw","quoteChar":null,"header":true,"delimiter":"\t"}

Followingnormalization, the value of thedialect property would then be:

"dialect":{"@id":"http://example.org/tab-separated-values","quoteChar":null,"header":true,"delimiter":"\t"}

5.1.6Natural Language Properties

Natural language properties hold natural language strings. Their values may be:

• strings — interpreted as natural language strings in thedefault language.
• arrays — interpreted as alternative natural language strings in thedefault language.
• objects whose propertiesMUST be language codes as defined by [BCP47] and whose values are either strings or arrays, providing natural language strings in that language.

Natural language properties are used for titles. For example, thetitles property on acolumn description provides a natural language label for a column. If it's a plain string like this:

"titles":"Project title"

then that string is assumed to be in thedefault language (or have an undefined language,und, if there is no such property). Multiple alternative values can be given in an array:

"titles":["Project title","Project"]

It's also possible to provide multiple values in different languages, using an object structure. For example:

"titles":{"en":"Project title","fr":"Titre du projet"}

and within such an object, the values of the properties can themselves be arrays:

"titles":{"en":["Project title","Project"],"fr":"Titre du projet"}

Theannotation value of anatural language property is an object whose properties are language codes and where the values of those properties are an array of strings (seeLanguage Maps in [JSON-LD]).

If the supplied value of a natural language property is not a string, array or object (e.g. if it is an integer), compliant applicationsMUST issue a warning and proceed as if the property had been specified as an empty array. If the supplied value is an array, any items in that array that are not stringsMUST be ignored. If the supplied value is an object, any properties that are not valid language codes as defined by [BCP47]MUST be ignored, as must any properties whose value is not a string or an array, and any items that are not strings within array values of these properties.

5.1.7Atomic Properties

Atomic properties holdatomic values. Their values may be:

• numbers — interpreted as integers or doubles.
• booleans — interpreted as booleans (true orfalse).
• strings — interpreted as defined by the property.
• objects — interpreted as defined by the property.
• arrays — lists of numbers, booleans, strings, or objects.

Theannotation value of a boolean atomic property isfalse if unset; otherwise, theannotation value of an atomic property isnormalized value of that property, or the defined default value ornull, if unset. ProcessorsMUST issue a warning if a property is set to an invalid value type, such as a boolean atomic property being set to the number1 or a numeric atomic property being set to the string"3.1415", and act as if the property had not been specified (which may mean using the default value for the property, or may mean raising an error and halting processing if the property is a required property).

5.3.1Required Properties

tables

Anarray property oftable descriptions for the tables in the group, namely those listed in thetables annotation on thegroup of tables being described. Compliant applicationMUST raise an error if this array does not contain one or more table descriptions.

5.3.2Optional Properties

The description of a group of tablesMAY also contain:

dialect

Anobject property that provides a singledialect description. If provided,dialect provides hints to processors about how to parse the referenced files to create tabular data models for the tables in the group. This may be provided as an embedded object or as a URL reference. Seesection5.9Dialect Descriptions for more details.

notes

Anarray property that provides an array of objects representing arbitrary annotations on the annotatedgroup of tables. The value of this property becomes the value of thenotes annotation for thegroup of tables. The properties on these objects are interpreted equivalently tocommon properties as described insection5.8Common Properties.

Note

TheWeb Annotation Working Group is developing a vocabulary for expressing annotations. In future versions of this specification, we anticipate referencing that vocabulary.

tableDirection

Anatomic property thatMUST have a single string value that is one of"rtl","ltr", or"auto". Indicates whether the tables in the group should be displayed with the first column on the right, on the left, or based on the first character in the table that has a specific direction. The value of this property becomes the value of thetable direction annotation for all the tables in the table group. SeeBidirectional Tables in [tabular-data-model] for details. The default value for this property is"auto".

tableSchema

Anobject property that provides a singleschema description as described insection5.5Schemas, used as the default for all the tables in the group. This may be provided as an embedded object within the JSON metadata or as a URL reference to a separate JSON object that is aschema description.

transformations

Anarray property oftransformation definitions that provide mechanisms to transform the tabular data into other formats. The value of this property becomes the value of thetransformations annotation for all the tables in the table group.

@id

If included,@id is alink property that identifies thegroup of tables, as defined by [tabular-data-model], described by thistable group description. ItMUST NOT start with_:. The value of this property becomes the value of theid annotation for thegroup of tables.

@type

If included,@type is anatomic property thatMUST be set to"TableGroup". PublishersMAY include this to provide additional information to JSON-LD based toolchains.

The descriptionMAY contain anycommon properties to provide extra metadata about the group of tables as a whole.

The descriptionMAY containinherited properties to describe cells within the tables.

5.3.3Table Group Description Compatibility

Twotable group descriptions arecompatible if anytable descriptions they contain with matchingnormalizedurl properties are themselvescompatible as defined insection5.4.3Table Description Compatibility.

5.4.1Required Properties

url

Thislink property gives the single URL of the CSV file that the table is held in, relative to the location of the metadata document. The value of this property is the value of theurl annotation for theannotated table this table description describes.

5.4.2Optional Properties

The description of a tableMAY also contain:

dialect

As defined fortable groups.

notes

Anarray property that provides an array of objects representing arbitrary annotations on theannotated tabular data model. The value of this property becomes the value of thenotes annotation for thetable. The properties on these objects are interpreted equivalently tocommon properties as described insection5.8Common Properties.

Note

TheWeb Annotation Working Group is developing a vocabulary for expressing annotations. In future versions of this specification, we anticipate referencing that vocabulary.

suppressOutput

A booleanatomic property. Iftrue, suppresses any output that would be generated when converting this table. The value of this property becomes the value of thesuppress output annotation for this table. The default isfalse.

tableDirection

As defined fortable groups. The value of this property becomes the value of thetable direction annotation for this table.

tableSchema

Anobject property that provides a singleschema description as described insection5.5Schemas. This may be provided as an embedded object within the JSON metadata or as a URL reference to a separate JSON schema document. If a table description is within atable group description, thetableSchema from that table group acts as the default for this property.

If atableSchema is not declared intable description, it may be declared on thetable group description, which is then used as theschema for thistable description.

The@id property of thetableSchema, if there is one, becomes the value of theschema annotation for this table.

Note

When a schema is referenced by URL, this URL becomes the value of the@id property in the normalized schema description, and thus the value of the schema annotation on the table.

transformations

As defined fortable groups. The value of this property becomes the value of thetransformations annotation for this table.

@id

If included,@id is alink property that identifies thetable, as defined in [tabular-data-model], described by thistable description. ItMUST NOT start with_:. The value of this property becomes the value of theid annotation for this table.

@type

If included,@type is anatomic property thatMUST be set to"Table". PublishersMAY include this to provide additional information to JSON-LD based toolchains.

The descriptionMAY contain anycommon properties to provide extra metadata about the table as a whole.

The descriptionMAY containinherited properties to describe cells within the table.

5.4.3Table Description Compatibility

Two table descriptions arecompatible if they have equivalentnormalizedurl properties, and havecompatibleschemas as defined insection5.5.1Schema Compatibility.

5.5.1Schema Compatibility

Two schemas arecompatible if they have the same number of non-virtualcolumn descriptions, and the non-virtualcolumn descriptions at the same index within each are compatible with each other.Column descriptions are compatible under the following conditions:

• If eithercolumn description has neithername nortitles properties.
• If there is a case-sensitive match between thename properties of the columns.
• If there is a non-empty case-sensitive intersection between thetitles values, where matches must have a matching language;und matches any language, and languages match if they are equal whentruncated, as defined in [BCP47], to the length of the shortest language tag.
• If not validating, and one schema has aname property but not atitles property, and the other has atitles property but not aname property.

5.5.2Examples

This section is non-normative.

countryCode,latitude,longitude,nameAD,42.5,1.6,AndorraAE,23.4,53.8,"United Arab Emirates"AF,33.9,67.7,Afghanistan

countryRef,year,populationAF,1960,9616353AF,1961,9799379AF,1962,9989846

{"@context":"http://www.w3.org/ns/csvw","tables":[{"url":"http://example.org/countries.csv","tableSchema":{"columns":[{"name":"countryCode","datatype":"string","propertyUrl":"http://www.geonames.org/ontology{#_name}"},{"name":"latitude","datatype":"number"},{"name":"longitude","datatype":"number"},{"name":"name","datatype":"string"}],"aboutUrl":"http://example.org/countries.csv{#countryCode}","propertyUrl":"http://schema.org/{_name}","primaryKey":"countryCode"}},{"url":"http://example.org/country_slice.csv","tableSchema":{"columns":[{"name":"countryRef","valueUrl":"http://example.org/countries.csv{#countryRef}"},{"name":"year","datatype":"gYear"},{"name":"population","datatype":"integer"}],"foreignKeys":[{"columnReference":"countryRef","reference":{"resource":"http://example.org/countries.csv","columnReference":"countryCode"}}]}}]}

Post Unique Reference,              Name,Grade,             Job Title,Reports to Senior Post                90115,        Steve Egan,SCS1A,Deputy Chief Executive,                 90334                90250,     David Sweeney,SCS1A,              Director,                 90334                90284,       Heather Fry,SCS1A,              Director,                 90334                90334,Sir Alan Langlands, SCS4,       Chief Executive,                    xx

Reporting Senior Post,Grade,Payscale Minimum (£),Payscale Maximum (£),Generic Job Title,Number of Posts in FTE,          Profession                90284,    4,               17426,               20002,    Administrator,                     2,Operational Delivery                90284,    5,               19546,               22478,    Administrator,                     1,Operational Delivery                90115,    4,               17426,               20002,    Administrator,                  8.67,Operational Delivery                90115,    5,               19546,               22478,    Administrator,                   0.5,Operational Delivery

{"@context":"http://www.w3.org/ns/csvw","tables":[{"url":"HEFCE_organogram_senior_data_31032011.csv","tableSchema":"http://example.org/schema/senior-roles.json"},{"url":"HEFCE_organogram_junior_data_31032011.csv","tableSchema":"http://example.org/schema/junior-roles.json"}]}

{"@id":"http://example.org/schema/senior-roles.json","@context":"http://www.w3.org/ns/csvw","columns":[{"name":"ref","titles":"Post Unique Reference"},{"name":"name","titles":"Name"},{"name":"grade","titles":"Grade"},{"name":"job","titles":"Job Title"},{"name":"reportsTo","titles":"Reports to Senior Post"}],"primaryKey":"ref"}

{"@id":"http://example.org/schema/junior-roles.json","@context":"http://www.w3.org/ns/csvw","columns":[{"name":"reportsTo","titles":"Reporting Senior Post"},...],"foreignKeys":[{"columnReference":"reportsTo","reference":{"schemaReference":"http://example.org/schema/senior-roles.json","columnReference":"ref"}}]}

{"@id":"http://example.org/schema/senior-roles.json","@context":"http://www.w3.org/ns/csvw","aboutUrl":"#role-{ref}","columns":[{"name":"ref","titles":"Post Unique Reference"},{"name":"name","titles":"Name"},{"name":"grade","titles":"Grade"},{"name":"job","titles":"Job Title"},{"name":"reportsTo","titles":"Reports to Senior Post","valueUrl":"#role-{reportsTo}"}],"primaryKey":"ref"}

"foreignKeys":[{"columnReference":"reportsTo","reference":{"schemaReference":"http://example.org/schema/senior-roles.json","columnReference":"ref"}}]

5.6.1Examples

This section is non-normative.

{"url":"tree-ops.csv","@context":["http://www.w3.org/ns/csvw",{"@language":"en"}],"tableSchema":{"columns":[{"name":"GID","titles":"GID","datatype":"string","propertyUrl":"schema:url","valueUrl":"#gid-{GID}"},{"name":"on_street","titles":"On Street","datatype":"string","aboutUrl":"#location-{GID}","propertyUrl":"schema:streetAddress"},{"name":"species","titles":"Species","datatype":"string","propertyUrl":"schema:name"},{"name":"trim_cycle","titles":"Trim Cycle","datatype":"string"},{"name":"inventory_date","titles":"Inventory Date","datatype":{"base":"date","format":"M/d/yyyy"},"aboutUrl":"#event-{inventory_date}","propertyUrl":"schema:startDate"},{"propertyUrl":"schema:event","valueUrl":"#event-{inventory_date}","virtual":true},{"propertyUrl":"schema:location","valueUrl":"#location-{GID}","virtual":true},{"aboutUrl":"#location-{GID}","propertyUrl":"rdf:type","valueUrl":"schema:PostalAddress","virtual":true}],"aboutUrl":"#gid-{GID}"}}

<#gid-1>  schema:url <#gid-1> ;  schema:name "Celtis australis" ;  :trim_cycle "Large Tree Routine Prune" ;schema:event <#event-2010-10-18> ;schema:location <#location-1> ;  .<#event-1> a schema:Event ;  schema:startDate "2010-10-18"^^xsd:date ;  .<#location-1> a schema:PostalAddress ;  schema:streetAddress "ADDISON AV" ;  .

{"@id":"#gid-1","schema:url":"#gid-1","schema:name":"Celtis australis","trim_cycle":"Large Tree Routine Prune","schema:event":{"@id":"#event-1","@type":"schema:Event","schema:startDate":"2010-10-18"},"schema:location":{"@id":"#location-1","@type":"schema:PostalAddress","schema:streetAddress":"ADDISON AV"}}

5.7.1Examples

This section is non-normative.

In the following example,aboutUrl property is defined on thetableSchema, and therefore affects all cells for that table.

{"@context":["http://www.w3.org/ns/csvw",{"@language":"en"}],"url":"tree-ops.csv","dc:title":"Tree Operations","dcat:keyword":["tree","street","maintenance"],"dc:publisher":{"schema:name":"Example Municipality","schema:url":{"@id":"http://example.org"}},"dc:license":{"@id":"http://opendefinition.org/licenses/cc-by/"},"dc:modified":{"@value":"2010-12-31","@type":"xsd:date"},"tableSchema":{"columns":[{"name":"GID","titles":["GID","Generic Identifier"],"dc:description":"An identifier for the operation on a tree.","datatype":"string","required":true},{"name":"on_street","titles":"On Street","dc:description":"The street that the tree is on.","datatype":"string"},{"name":"species","titles":"Species","dc:description":"The species of the tree.","datatype":"string"},{"name":"trim_cycle","titles":"Trim Cycle","dc:description":"The operation performed on the tree.","datatype":"string"},{"name":"inventory_date","titles":"Inventory Date","dc:description":"The date of the operation that was performed.","datatype":{"base":"date","format":"M/d/yyyy"}}],"primaryKey":"GID","aboutUrl":"#gid-{GID}"}}

The equivalent effect could be achieved by using theaboutUrl property on each column:

{"@context":["http://www.w3.org/ns/csvw",{"@language":"en"}],"url":"tree-ops.csv","dc:title":"Tree Operations","dcat:keyword":["tree","street","maintenance"],"dc:publisher":{"schema:name":"Example Municipality","schema:url":{"@id":"http://example.org"}},"dc:license":{"@id":"http://opendefinition.org/licenses/cc-by/"},"dc:modified":{"@value":"2010-12-31","@type":"xsd:date"},"tableSchema":{"columns":[{"name":"GID","titles":["GID","Generic Identifier"],"aboutUrl":"#gid-{GID}","dc:description":"An identifier for the operation on a tree.","datatype":"string","required":true},{"name":"on_street","titles":"On Street","aboutUrl":"#gid-{GID}","dc:description":"The street that the tree is on.","datatype":"string"},{"name":"species","titles":"Species","aboutUrl":"#gid-{GID}","dc:description":"The species of the tree.","datatype":"string"},{"name":"trim_cycle","titles":"Trim Cycle","aboutUrl":"#gid-{GID}","dc:description":"The operation performed on the tree.","datatype":"string"},{"name":"inventory_date","titles":"Inventory Date","aboutUrl":"#gid-{GID}","dc:description":"The date of the operation that was performed.","datatype":{"base":"date","format":"M/d/yyyy"}}],"primaryKey":"GID"}}

5.8.1Names of Common Properties

The names of common properties areprefixed names, in the syntaxprefix:name.

Prefixed names can beexpanded to provide a URI, by replacing the prefix and following colon with the URI that the prefix is associated with. Expansion is intended to be entirely consistent withSection 6.3 IRI Expansion in [JSON-LD-API] and implementationsMAY use a JSON-LD processor for performing prefixed name and IRI expansion.

The prefixes that are recognized are those defined for [rdfa-core] within theRDFa 1.1 Initial Context and other prefixes defined within [csvw-context] and theseMUST NOT be overridden. These prefixes are periodically extended; refer to [csvw-context] for details. Properties from other vocabulariesMUST be named using absolute URLs.

This specification does not define how common properties are interpreted by implementations. ImplementationsSHOULD treat theprefixed names for common properties and the URLs that they expand into in the same way. For example, if an implementation recognises and displays the value of thedc:description property, it should also recognise and display the value of thehttp://purl.org/dc/terms/description property in the same way.

5.8.2Values of Common Properties

Common properties can take any JSON value, so long as any objects within the value (for example as items of an array or values of properties on other objects) adhere to the following restrictions, which are designed to ensure compatibility between JSON-LD-aware and non-JSON-LD-aware processors:

• If a@value property is used on an object, that objectMUST NOT have any other properties aside from either@type or@language, andMUST NOT have both@type and@language as properties. The value of the@value propertyMUST be a string, number, or boolean value.

  If@type is also used, its valueMUST be one of:

  • a built-in datatype, as defined insection5.11.1Built-in Datatypes.
  • aprefixed name using any of the pre-defined prefixes as described insection5.8.1Names of Common Properties.
  • a string, whichMUST be interpreted as an absolute URL.

  If a@language property is used, itMUST have a string value that adheres to the syntax defined in [BCP47], or benull.

• If a@type property is used on an object without a@value property, its valueMUST be one of:

  • one of the legitimate values for@type as defined for any of the description objects in this specification.
  • aprefixed name using any of the pre-defined prefixes as described insection5.8.1Names of Common Properties.
  • a string, whichMUST be interpreted as an absolute URL.

  A@type property can also have a value that is an array of such values.

• The values of@id properties arelink properties and are treated as URLs. Duringnormalization, as described insection6.Normalization, they will have any prefixexpanded and the result resolved against thebase URL. Therefore, if an@id property is used on an object, itMUST have a value that is a string and that stringMUST NOT start with_:.

• A@language propertyMUST NOT be used on an object unless it also has a@value property.

• Aside from@value,@type,@language, and@id, the properties used on an objectMUST NOT start with@.

These restrictions are also described insectionA.JSON-LD Dialect, from the perspective of a processor that otherwise supports JSON-LD. Examples of common property values and the impact ofnormalization are given insection6.1Examples.

5.10.1Required Properties

Transformation definitionsMUST have the following properties:

url

Alink property giving the single URL of the file that the script or template is held in, relative to the location of the metadata document.

scriptFormat

Alink property giving the single URL for the format that is used by the script or template. If one has been defined, this should be a URL for a media type, in the formhttp://www.iana.org/assignments/media-types/media-type such ashttp://www.iana.org/assignments/media-types/application/javascript. Otherwise, it can be any URL that describes the script or template format.

Note

ThescriptFormat URL is intended as an informative identifier for the template format, and applicationsSHOULD NOT access the URL. The template formats that an application supports are implementation defined.

targetFormat

Alink property giving the single URL for the format that will be created through the transformation. If one has been defined, this should be a URL for a media type, in the formhttp://www.iana.org/assignments/media-types/media-type such ashttp://www.iana.org/assignments/media-types/text/calendar. Otherwise, it can be any URL that describes the target format.

Note

ThetargetFormat URL is intended as an informative identifier for the target format, and applicationsSHOULD NOT access the URL.

5.10.2Optional Properties

Transformation definitionsMAY have the following properties:

source

A single stringatomic property that provides, if specified, the format to which the tabular data should be transformed prior to the transformation using the script or template. If the value isjson, the tabular dataMUST first be transformed to JSON as defined by [csv2json] usingstandard mode. If the value isrdf, the tabular dataMUST first be transformed to an RDF graph as defined by [csv2rdf] usingstandard mode. If thesource property is missing ornull (the default) then the source of the transformation is theannotated tabular data model. No other values are valid; applicationsMUST generate a warning and behave as if the property had not been specified.

titles

Anatural language property that describes the format that will be generated from the transformation. This is useful if the target format is a generic format (such asapplication/json) and the transformation is creating a specific profile of that format.

@id

If included,@id is alink property that identifies the transformation described by thistransformation definition. ItMUST NOT start with_:.

@type

If included,@type is anatomic property thatMUST be set to"Template". PublishersMAY include this to provide additional information to JSON-LD based toolchains.

The transformation definitionMAY contain anycommon properties to provide extra metadata about the transformation.

5.10.3Processing Transformation Definitions

ImplementationsMAY present users with options for transformations based on the availabletransformation definitions and their properties. ImplementationsSHOULD filter this list to only include those transformations whosescriptFormat they understand and can apply, and whosesource property, if present, specifies a format that the implementation can convert to. Users may find thetargetFormat andtitles properties useful in deciding which transformation to apply.

When directed by a user to transform a table using atransformation definition, implementationsMUST:

1. Convert the table to the format specified by thesource property, if this is specified and notnull.
2. Fetch the script or template from the location specified by theurl property and raise an error if this does not exist.
3. Use thescriptFormat property to determine how to interpret that script or template, and apply it to the table (or the result of converting the table).

5.11.1Built-in Datatypes

The possible built-in datatypes, as shown onthe diagram, are:

• the datatypes defined in [xmlschema11-2] as derived from and includinganyAtomicType, whose identifier URLs are generated by prefixing the name withhttp://www.w3.org/2001/XMLSchema#.
• the datatypenumber whose identifier URL ishttp://www.w3.org/2001/XMLSchema#double.
• the datatypebinary whose identifier URL ishttp://www.w3.org/2001/XMLSchema#base64Binary.
• the datatypedatetime whose identifier URL ishttp://www.w3.org/2001/XMLSchema#dateTime.
• the datatypeany whose identifier URL ishttp://www.w3.org/2001/XMLSchema#anyAtomicType.
• the datatypexml, a sub-type ofstring, whose identifier URL ishttp://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral and which indicates the value is an XML fragment.
• the datatypehtml, a sub-type ofstring, whose identifier URL ishttp://www.w3.org/1999/02/22-rdf-syntax-ns#HTML and which indicates the value is an HTML fragment.
• the datatypejson, a sub-type ofstring, whose identifier URL ishttp://www.w3.org/ns/csvw#JSON and which indicates the value is serialized JSON.

5.11.2Derived Datatypes

More specialized datatypes can be defined through adatatype description. A datatype description may have any of the following properties, all of which are optional.

base

Anatomic property that contains a single string: the name of one of the built-in datatypes, as listed above (and which are defined asterms in the default context). Its default isstring. All values of the datatypeMUST be valid values of the base datatype. The value of this property becomes thebase annotation for the describeddatatype.

format

Anatomic property that contains either a single string or an object that defines the format of a value of this type, used when parsing a string value as described inParsing Cells in [tabular-data-model]. The value of this property becomes theformat annotation for the describeddatatype.

length

A numericatomic property that contains a single integer that is the exact length of the value. The value of this property becomes thelength annotation for the describeddatatype. SeeLength Constraints in [tabular-data-model] for details.

minLength

Anatomic property that contains a single integer that is the minimum length of the value. The value of this property becomes theminimum length annotation for the describeddatatype. SeeLength Constraints in [tabular-data-model] for details.

maxLength

A numericatomic property that contains a single integer that is the maximum length of the value. The value of this property becomes themaximum length annotation for the describeddatatype. SeeLength Constraints in [tabular-data-model] for details.

minimum

Anatomic property that contains a single number or string that is the minimum valid value (inclusive); equivalent tominInclusive. The value of this property becomes theminimum annotation for the describeddatatype. SeeValue Constraints in [tabular-data-model] for details.

maximum

Anatomic property that contains a single number or string that is the maximum valid value (inclusive); equivalent tomaxInclusive. The value of this property becomes themaximum annotation for the describeddatatype. SeeValue Constraints in [tabular-data-model] for details.

minInclusive

Anatomic property that contains a single number or string that is the minimum valid value (inclusive). The value of this property becomes theminimum annotation for the describeddatatype. SeeValue Constraints in [tabular-data-model] for details.

maxInclusive

Anatomic property that contains a single number or string that is the maximum valid value (inclusive). The value of this property becomes themaximum annotation for the describeddatatype. SeeValue Constraints in [tabular-data-model] for details.

minExclusive

Anatomic property that contains a single number or string that is the minimum valid value (exclusive). The value of this property becomes theminimum exclusive annotation for the describeddatatype. SeeValue Constraints in [tabular-data-model] for details.

maxExclusive

Anatomic property that contains a single number or string that is the maximum valid value (exclusive). The value of this property becomes themaximum exclusive annotation for the describeddatatype. SeeValue Constraints in [tabular-data-model] for details.

@id

If included,@id is alink property that identifies the datatype described by thisdatatype description. The value of this property becomes theid annotation for the describeddatatype. ItMUST NOT start with_: and itMUST NOT be the URL of a built-in datatype.

@type

If included,@type is anatomic property thatMUST be set to"Datatype". PublishersMAY include this to provide additional information to JSON-LD based toolchains.

Thedatatype descriptionMAY contain anycommon properties to provide extra metadata about the datatype, such as a title or description.

ApplicationsMUST raise an error if the@id property has the value of a built-in datatype and any other property is specified. In these cases, the other properties are ignored.

ApplicationsMUST raise an error if bothlength andminLength are specified andlength is less thanminLength. Similarly, applicationsMUST raise an error if bothlength andmaxLength are specified andlength is greater thanmaxLength. ApplicationsMUST raise an error ifminLength andmaxLength are both specified andminLength is greater thanmaxLength. ApplicationsMUST raise an error iflength,maxLength, orminLength are specified and thebase datatype is neitherstring, a subtype ofstring, nor a binary type.

In all ways, including the errors described below, theminimum property is equivalent to theminInclusive property and themaximum property is equivalent to themaxInclusive property. ApplicationsMUST raise an error if bothminimum andminInclusive are specified and they do not have the same value. Similarly, applicationsMUST raise an error if bothmaximum andmaxInclusive are specified and they do not have the same value.

ApplicationsMUST raise an error if bothminInclusive andminExclusive are specified, or if bothmaxInclusive andmaxExclusive are specified. ApplicationsMUST raise an error if bothminInclusive andmaxInclusive are specified andmaxInclusive is less thanminInclusive, or if bothminInclusive andmaxExclusive are specified andmaxExclusive is less than or equal tominInclusive. Similarly, applicationsMUST raise an error if bothminExclusive andmaxExclusive are specified andmaxExclusive is less thanminExclusive, or if bothminExclusive andmaxInclusive are specified andmaxInclusive is less than or equal tominExclusive.

ApplicationsMUST raise an error ifminimum,minInclusive,maximum,maxInclusive,minExclusive, ormaxExclusive are specified and thebase datatype is not a numeric, date/time, or duration type.

Validation against these properties is as defined in [xmlschema11-2].

{  "datatype": "date",  "format": "dd/MM/yyyy",  "minimum": "2000-01-01"}