One of the purposes of these community docs was to help with this main key concept and help guide you on your development path using Dgraph. If you go to the official Dgraph Docs, you will notice that the docs are split between GraphQL and DQL.
What is DQL?
If this is your first time to Dgraph, you may have heard of GraphQL before, but what is DQL?
DQL is Dgraph Query Language developed by Dgraph. It was originally named graphql+-, but this was changed over time to prevent even more confusion between GraphQL and DQL.
If this is your first time hearing about GraphQL, that is not a problem either as these community docs will start at ground zero for the GraphQL beginners and serve as a GraphQL fundamental review for GraphQL experts.
Why the need for DQL?
GraphQL is a great language structure for working with an API, but it was never intended to be used as a database query language. Dgraph liked GraphQL and chose to fashion their graph database language around the concepts of GraphQL, but add in their own unique syntax structures to develop a language that can be used to handle core database functions.
Before Dgraph version 20.03, which began the calendar versioning of Dgraph, the core of Dgraph only had endpoints for DQL and was lacking a spec-compliant GraphQL endpoint. Anybody who wanted to have a GraphQL API to use for their front-end applications had to write their own backend layer with their own resolvers. Version 20.03 brought the spec-compliant GraphQL endpoint into the core of Dgraph, without removing the DQL endpoints. The GraphQL endpoint could be understood as a layer around the DQL endpoints because it takes the GraphQL queries and mutations and rewrites them to DQL. I say it is not wrapping layer though because it is all inside of the core of the Dgraph codebase. The functions live together in the same repo and are deployed as a single self-contained database having both the DQL and GraphQL endpoints.
No DQL Needed :)
Since Dgraph v. 20.03, you can start using Dgraph without needing any DQL.
You can deploy and start using Dgraph with only a working knowledge of GraphQL, as you will see in these docs.
So when might you need to use DQL? Here are a few scenarios when to use DQL:
- Ingesting data in bulk
- Dropping data in bulk
- Using Dgraph for loosely typed or untyped data
- Migrating data after schema changes
Using GraphQL and DQL together.
It is possible to use GraphQL and DQL together. These community docs are focusing specically on GraphQL, but will contain tidbits and advanced topics to help show you what you need to know to use these two languages together.
If you want a side by side comparison for DQL and GraphQL along with pointers of when to use which one, then check the blog post:
GraphQL vs DQL
by Anthony Master