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Compare with Wikibase tabular data model (#990)
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| title: Comparison with MediaWiki Tabular Data | ||
| sidebar: | ||
| order: 3 | ||
| --- | ||
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| <table> | ||
| <tr> | ||
| <th>Authors</th> | ||
| <td>Jakob Voß</td> | ||
| </tr> | ||
| </table> | ||
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| [MediaWiki](https://www.mediawiki.org/) is the software used to run Wikipedia and related projects of the Wikimedia Foundation, including the media file repository [Wikimedia Commons](https://commons.wikimedia.org/). Commons hosts mostly images but also some records with tabular data. The [MediaWiki Tabular Data Model](https://www.mediawiki.org/wiki/Help:Tabular_data) was inspired by Data Package version 1 but it slightly differs from current Data Package specification, as described below. | ||
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| ## Property Comparison | ||
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| A [MediaWiki tabular data page](https://www.mediawiki.org/wiki/Help:Tabular_data) describes and contains an individual table of data similar to a [Data Resource](/standard/data-resource/) with inline tabular data. Both are serialized as JSON objects, but the former comes as a page with unique name in a MediaWiki instance (such as Wikimedia Commons). | ||
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| ### Top-level Properties | ||
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| MediaWiki Tabular Data has three required and two optional top-level properties. Most of these properties map to corresponding properties of a Data Resource: | ||
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| | MediaWiki Tabular Data | Data Package Table Schema | ||
| |--|--| | ||
| | - (implied by page name) | [name](/standard/data-resource/#name) (required) is a string | ||
| | [description](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (optional) is a localized string | [description](/standard/data-resource/#description) (optional) is a string | ||
| | [data](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (required) | [data](/standard/data-resource/#name) (optional) | ||
| | [license](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (required) is the string `CC-1.0` or another known identifier | [licenses](/standard/data-resource/#licenses) (optional) is an array | ||
| | [schema](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (required) as [described below](#schema-properties) | [schema](/standard/data-resource/#schema) (optional) can have multiple forms | ||
| | [sources](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (optional) is a string with Wiki markup | [sources](/standard/data-resource/#sources) (optional) is a an array of objects | ||
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| The differences are: | ||
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| - property `name` does not exist but can be implied from page name | ||
| - property `description` and `sources` have another format | ||
| - property `data` is always an array of arrays and [data types](#data-types) of individual values can differ | ||
| - property `schema` is required but it differs in definion of [schema properties](#schema-properties) | ||
| - there is no property `licenses` but `license` fixed to plain string value `CC0-1.0` (other license indicators may be possible) | ||
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| ### Data Types | ||
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| Tabular Data supports four data types that overlap with [Table Schema data types](/standard/table-schema/#field-types): | ||
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| - `number` subset of Table Schema [number](/standard/table-schema/#number) (no NaN, INF, or -INF) | ||
| - `boolean` same as Table Schema [boolean](/standard/table-schema/#boolean) | ||
| - `string` subset of Table Schema [string](/standard/table-schema/#string) (limited to 400 characters at most and must not include `\n` or `\t`) | ||
| - `localized ` refers to an object that maps language codes to strings with same limitations as `string` type. | ||
| This type is not supported in Table Schema. | ||
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| Indiviual values in a MediaWiki Tabular Data table can always be `null`, while in Table Schema you need to explicitly list values that should be considered missing in [schema.missingValues](/standard/table-schema/#missingValues). | ||
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| ### Schema Properties | ||
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| The `schema` property of MediaWiki tabular contains an object with property `fields` just like [Table Schema](/standard/table-schema/) but no other properties are allowed. Elements of this array are like Table Schema [field descriptors](/standard/table-schema/#field) limited to three properties and different value spaces: | ||
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| | MediaWiki Tabular Data | Data Package Table Schema | ||
| |--|--| | ||
| | [name](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (required) must be a string matching `^[a-zA-Z_][a-zA-Z_0-9]*` | [name](/standard/table-schema/#name) (required) can be any string | ||
| | [type](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (required) is one of the [Data Types above](#data-types) | [type](/standard/table-schema/#type) (optional) with [different data types](#data-types) | ||
| | [title](https://www.mediawiki.org/wiki/Help:Tabular_data#Top-level_fields) (optional) is a localized string | [title](/standard/table-schema/#title) (optional) is a plain string | ||
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