- describe files and licences

Database.md

@@ -43,11 +43,11 @@ TETHYS provides an Access Control List (ACL) system that is used to manage users
 Many research repositories allow you to filter content based on specific criteria. For example, you may be able to filter by publication date, author, contributor, title, abstract, keyword or spatially via coverage. This can be helpful if you are looking for a specific type of resource or trying to narrow down your search results. TETHYS also organizes content into collections based on specific themes or topics. Collections can be a great way to quickly find relevant resources and may be curated by experts in the field.
 ![title](./tethys_filter.png)
 
-* **datset_abstracts**: This table stores all the descriptions to an uploaded dataset. Allowed values for an abstract type are: 'Abstract', 'Methods', 'Series_information',  'Technical_info', 'Translated' and 'Other'. 
+* **datset_abstracts**: This table stores all the descriptions to an uploaded dataset. Allowed values for an abstract type are: 'Abstract', 'Methods', 'Series_information',  'Technical_info', 'Translated' and 'Other'. For ech abstract you have to select the language.
 
-* **datset_titles**: This table stores all the titles to an uploaded dataset. Allowed values for a title type are: 'Main', 'Sub', 'Alternative',  'Translated' and 'Other'. 
+* **datset_titles**: This table stores all the titles to an uploaded dataset. Allowed values for a title type are: 'Main', 'Sub', 'Alternative',  'Translated' and 'Other'. For ech title you have to select the language. 
 
-* **dataset_subjects** with pivot table link_dataset_subjects: This table stores all the keywords. Until now only uncontrolled keywords are possible (attribute type is default 'uncontrolled')
+* **dataset_subjects** with pivot table link_dataset_subjects: This table stores all the keywords. Until now only uncontrolled keywords are possible (attribute type is default 'uncontrolled'). The attribute 'external_key' you will need for refencing controlled subjects.
 
 * **datset_abstracts**: This table stores all the descriptions to an uploaded dataset. Allowed values for an abstract type are: 'Abstract', 'Methods', 'Series_information',  'Technical_info', 'Translated' and 'Other'. 
 
@@ -65,14 +65,21 @@ In the pivot table there are attributes for:
 <br />
 
 ## Tables for file metadata and file checksums:
+TETHYS stores metadata about all files in a separate database table ('document_files').
 ![title](./tethys_file.png)
 * **document_files**: TETHY stores the following metadata attributes for every uploaded file:
     * path_name: path to the file on the harddisk
     * label: name of the file presented aon the web frontend
     * comment: optional comments to files are possible
-    * mime_type:
+    * mime_type
-    * file_size
+    * file_size in bytes
     * visible_frontdoo: is the file visible on the web frontend
     * visible_oai: is the file vissible iin the oai response
+    * sort_order: for the order aof all files associated to a dataset
+    * timestamp attributes: created_at and update_at
+
 * **file_hashvalues**:
-TETHYS RDR calculates internal checksums during the ingestion workflow. These checksums ensure that ingested data has not been altered or damaged. A checksum is a short sequence of bits or bytes that is calculated from the data using an algorithm. If even a single bit of the data changes, the checksum will also change, indicating that the data has been changed unintentionally on the file store. During the file upload, TETHYS calculates and stores md5 and sha512-checksums for each file.
+TETHYS RDR calculates internal checksums during the ingestion workflow. These checksums ensure that ingested data has not been altered or damaged. A checksum is a short sequence of bits or bytes that is calculated from the data using an algorithm. If even a single bit of the data changes, the checksum will also change, indicating that the data has been changed unintentionally on the file store. During the file upload, TETHYS calculates and stores md5 and sha512-checksums for each file (see attribute type).
+
+* **document_licences** with pivot table 'link_document_licences':
+Creative Commons licenses are commonly used to govern the use and distribution of research data. For example, a researcher might choose to make their research data available under a CC-BY license, which allows others to share, adapt, and build upon the data as long as they provide attribution to the original author. All preferred CC licences for TETHYS are described in the manual (https://tethys.at/docs/HandbuchTethys.pdf p 15).