OData is a protocol for accessing Web resources. OData builds directly on HTTP and expands it with query language specifications. The aim is data access over the Internet allowing complex queries with filtering and sorting. Model for OData is the SQL database language. Language constructs that are used in SQL, are defined as elements for the URI in an altered form.
As a result, a Web resource that is deployed with OData can be seen as a database which records are available via the Internet. Relations between the tables are realized with URLs in the records. Additionally, thanks to the REST-compliant implementation, records can be created, changed and deleted. APP and JSON are available as formats for the transmission of user data.
More information is available at https://www.odata.org.