Installation¶

Installation of Skosprovider_sqlalchemy is easily done using pip.

$ pip install skosprovider_sqlalchemy

Creating a database¶

Since Skosprovider_sqlalchemy implements the SkosProvider interface with a relational database as a backend, you first need to create this database. To do this, please follow the instructions of your database software. If you’re working with SQLite, you don’t need to do anything.

Once your database has been created, you can initialise it with the necessary database tables that will contain your SKOS vocabularies and concepts.

$ init_skos_db sqlite:///vocabs.db

Let’s have a look at what this script did.

$ sqlite3 vocabs.db
SQLite version 3.7.9 2011-11-01 00:52:41
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .tables
collection_concept            conceptscheme_note
concept                       label
concept_hierarchy_collection  labeltype
concept_hierarchy_concept     language
concept_label                 match
concept_note                  matchtype
concept_related_concept       note
conceptscheme                 notetype
conceptscheme_label           visitation

Providers module¶

class skosprovider_sqlalchemy.providers.SQLAlchemyProvider(metadata, session_maker, **kwargs)[source]¶

A skosprovider.providers.VocabularyProvider that uses SQLAlchemy as backend.

expand_strategy = 'recurse'¶

Determines how the expand method will operate. Options are:

• recurse: Determine all narrower concepts by recursivly querying the database. Can take a long time for concepts that are at the top of a large hierarchy.
• visit: Query the database’s Visitation table. This table contains a nested set representation of each conceptscheme. Actually creating the data in this table needs to be scheduled.

Models module¶

class skosprovider_sqlalchemy.models.Collection(**kwargs)[source]¶

A collection as know by SKOS.

class skosprovider_sqlalchemy.models.Concept(**kwargs)[source]¶

A concept as know by SKOS.

class skosprovider_sqlalchemy.models.ConceptScheme(**kwargs)[source]¶

A SKOS conceptscheme.

class skosprovider_sqlalchemy.models.Initialiser(session)[source]¶

Initialises a database.

Adds necessary values for labelType, noteType and language to the database.

The list of languages added by default is very small and will probably need to be expanded for your local needs.

init_all()[source]¶

Initialise all objects (labeltype, notetype, language).

init_labeltype()[source]¶

Initialise the labeltypes.

init_languages()[source]¶

Initialise the languages.

Only adds a small set of languages. Will probably not be sufficient for most use cases.

init_matchtypes()[source]¶

Initialise the matchtypes.

init_notetype()[source]¶

Initialise the notetypes.

class skosprovider_sqlalchemy.models.Label(label, labeltype_id=u'prefLabel', language_id=None)[source]¶

A label for a Concept, Collection or ConceptScheme.

class skosprovider_sqlalchemy.models.LabelType(name, description)[source]¶

A labelType according to SKOS.

class skosprovider_sqlalchemy.models.Language(id, name)[source]¶

A Language.

class skosprovider_sqlalchemy.models.Match(**kwargs)[source]¶

A match between a Concept in one ConceptScheme and those in another one.

class skosprovider_sqlalchemy.models.MatchType(name, description)[source]¶

A matchType according to SKOS.

class skosprovider_sqlalchemy.models.Note(note, notetype_id, language_id, markup=None)[source]¶

A note for a Concept, Collection or ConceptScheme.

class skosprovider_sqlalchemy.models.NoteType(name, description)[source]¶

A noteType according to SKOS.

class skosprovider_sqlalchemy.models.Source(citation, markup=None)[source]¶

The source where a certain piece of information came from.

class skosprovider_sqlalchemy.models.Thing(**kwargs)[source]¶

Abstract class for both Concept and Collection.

class skosprovider_sqlalchemy.models.Visitation(**kwargs)[source]¶

Holds several nested sets.

The visitation object and table hold several nested sets. Each skosprovider_sqlalchemy.models.Visitation holds the positional information for one conceptplacement in a certain nested set.

Each conceptscheme gets its own separate nested set.

skosprovider_sqlalchemy.models.label(labels=[], language=u'any', sortLabel=False)[source]¶

Provide a label for a list of labels.

Deprecated since version 0.5.0: Please use skosprovider.skos.label(). Starting with skosprovider 0.6.0, the function can function on skosprovider_sqlalchemy.models.Label instances as well.

Parameters:	labels (list) – A list of labels. language (str) – The language for which a label should preferentially be returned. This should be a valid IANA language tag. sortLabel (boolean) – Should sortLabels be considered or not? If True, sortLabels will be preferred over prefLabels. Bear in mind that these are still language dependent. So, it’s possible to have a different sortLabel per language.
Return type:	A Label or None if no label could be found.

skosprovider_sqlalchemy.models.related_concepts_append_listener(target, value, initiator)[source]¶

Listener that ensures related concepts have a bidirectional relationship.

skosprovider_sqlalchemy.models.related_concepts_remove_listener(target, value, initiator)[source]¶

Listener to remove a related concept from both ends of the relationship.

Utils module¶

class skosprovider_sqlalchemy.utils.VisitationCalculator(session)[source]¶

Generates a nested set for a conceptscheme.

visit(conceptscheme)[source]¶

Visit a skosprovider_sqlalchemy.models.Conceptscheme and calculate a nested set representation.

Parameters:	conceptscheme – A skosprovider_sqlalchemy.models.Conceptscheme for which the nested set will be calculated.

skosprovider_sqlalchemy.utils.import_provider(provider, conceptscheme, session)[source]¶

Import a provider into a SQLAlchemy database.

Parameters:	provider – The skosprovider.providers.VocabularyProvider to import. Since the SQLAlchemy backend uses integers as keys, this backend should have id values that can be cast to int. conceptscheme – A skosprovider_sqlalchemy.models.Conceptscheme to import the provider into. This should be an empty scheme so that there are no possible id clashes. session – A sqlalchemy.orm.session.Session.

0.5.0 (2016-08-11)¶

• Update to skosprovider 0.6.0
• Minor BC break: A skosprovider_sqlalchemy.models.Language that gets cast to a string, now returns the language’s ID (the IANA language code),as opposed to the language’s description it would previously return.
• Minor BC break: The URI attribute has been made required for a skosprovider_sqlalchemy.models.ConceptScheme. Before it was optional, but it probably would have caused problems with skosprovider anyway.
• Due to the update to skosprovider 0.6.0, a new field markup, was added to a skosprovider_sqlalchemy.models.Note. When upgrading from a previous version of skosprovider_sqlalchemy, any databases created in that previous verions will need to be updated as well. Please add a field called markup to the note table.
• Inline with the skosprovider 0.6.0 update, a languages attribute was added to skosprovider_sqlalchemy.models.ConceptScheme. When upgrading from a previous version of skosprovider_sqlalchemy, any databases created with that previous verions will need to be updated as well. Please add a table called conceptscheme_language with fields conceptscheme_id and language_id. (#18)
• To comply with the skosprovider 0.6.0 update, the sources attribute was added to skosprovider_sqlalchemy.models.Conceptscheme, skosprovider_sqlalchemy.models.Concept and skosprovider_sqlalchemy.models.Collection. When upgrading from a previous version of skosprovider_sqlalchemy, any databases created with that previous verions will need to be updated as well. Please add a table source with fields id, citation and markup, a table concept_source with fields concept_id and source_id and a table conceptscheme_source with fields conceptscheme_id and source_id.
• All methodes that return a list have been modified in line with skosprovider 0.6.0 to support sorting. Sorting is possible on id, uri, label and sortlabel. The last two are language dependent. The sortlabel allows custom sorting of concepts. This can be used to eg. sort concepts representing chronological periods in chronological in stead of alphabetical order. (#20)
• To comply with the skosprovider 0.6.0 update, the deprecated skosprovider_sqlalchemy.providers.SQLAlchemyProvider.expand_concept() was removed.
• When importing a provider, check if the languages that are being used in the provider are already in our database. If not, validate them and add them to the database. In the past the entire import would fail if not all languages had previously been added to the database. (#14)
• When importing a provider, try to import as much information as possible about the concept_scheme that’s attached to the provider. (#19)
• When querying for indvidual an conceptscheme or concept, use joinedload to reduce the number of queries needed to collect everything. (#15)
• Deprecated the skosprovider_sqlalchemy.models.label() function. Please use skosprovider.skos.label() from now once, since this function can now operate on both skosprovider.skos.Label and skosprovider_sqlalchemy.models.Label instances. This was the reason for the BC break in this release.

0.4.2 (2015-03-02)¶

• Make README work better on pypi.
• Fix a further problem with the length of language identifiers. Previous fix in 0.3.0 only fixed the length of the identifiers in the languages table, but not in the links from the labels and the notes to the language table. [BartSaelen]
• Added some documentation about setting up a database.

0.4.1 (2014-12-18)¶

• Fix a bug with the deletion of a Concept not being possible without having it’s matches deleted first. [BartSaelen]

0.4.0 (2014-10-28)¶

• Major BC break: A provider is no longer passed a database session, but a database session maker. This change was needed to get the provider to function properly in threaded web applications. This will mean changing the code where you’re creating your provider. In the past, you probably called a session maker first and then passed the result of this call to the provider. Now you should just pass the session maker itself and let the provider create the sessions for you.
• Different way of fetching the ConceptScheme for a provider. No longer fetches a conceptscheme at provider instantiation, but when needed. Otherwise we end up with a possibly very long cached version of a conceptscheme.

0.3.0 (2014-10-17)¶

• Update to skosprovider 0.4.0.
• Add ConceptScheme information to a provider so it can be attached to Concept objects that are handled by the provider.
• Let provider handle superordinates and subordinate arrays.
• Let provider add notes to collections.
• Added a Match model to handle matches. Expand the provider to actually provide information on these matches.
• Expand the field length for language identifiers. IANA suggests that identifiers up to 35 characters should be permitted. Updated our field length to 64 to have a bit of an extra buffer.

0.2.1 (2014-08-25)¶

• Switch to py.test
• Add Coveralls support for code coverage.
• Add ability to configure the SQLAlchemy URL used for testing. Allows testing on multiple RDBMS systems.
• Run Travis tests for both SQLite and Postgresql.
• Fix a bug in skosprovider_sqlalchemy.utils.import_provider() when dealing with narrower collections (#8). [cahytinne]
• Make the provider actually generate a URI if there’s none in the database.

0.2.0 (2014-05-14)¶

• Compatibility with skosprovider 0.3.0
• Implement skosprovider.providers.VocabularyProvider.get_by_uri().
• Implement skosprovider.providers.VocabularyProvider.get_top_concepts().
• Implement skosprovider.providers.VocabularyProvider.get_top_display() and skosprovider.providers.VocabularyProvider.get_children_display().
• Add a UniqueConstraint(conceptscheme_id, concept_id) to Thing. (#3)
• Rename the colletions attribute of skosprovider_sqlalchemy.models.Thing to member_of. (#7)

0.1.2 (2013-12-06)¶

• Pinned dependency on skosprovider < 0.3.0
• Pass data to skosprovider.skos.Concept using keywords in stead of positions.

0.1.1 (2013-11-28)¶

• Fixed a bug with collection members being passed instead of their ids.
• Fixed another bug where model ids were used instead of concept ids.

0.1.0¶

• Initial version
• Implementation of a SKOS domain model in SQLAlchemy.
• Implementation of a skosprovider.providers.VocabularyProvider that uses this model.
• Can query a hierarchy recursively or using nested sets.
• Utility function to import a skosprovider.providers.VocabularyProvider in a database.