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Dgraph DQL Tour

Var Blocks

Query Variables in a child block

Query variables in a child block allow the query to carry answers matched at one level down to the children to filter against.

For example, take of the set of actors in all Jane Campion films; our challenge is to find which pairs in that set have acted together on a film not directed by Jane Campion.

The query here uses the sets of all Jane Campion’s films JC_films and all actors in any Jane Campion film JC_actors in child blocks.

The @cascade directive ensures answers match all parts of the query - otherwise, actors who had no matching co-actors could be returned.

The query returns the trivial matches of actors and themselves as well as other coactors.

The same query could have been written using variables that span multiple queries, but the graph traversal would be the same.

Dgraph DQL Tour

An interactive tutorial with real queries and real results, designed to run on Chrome on your machine.

Modules

. GraphQL Introduction . GraphQL Basic Features . GraphQL Schema . GraphQL Search . GraphQL Data and More Data . DQL Introduction . DQL Basic Features . DQL Schema . DQL Data and More Data . DQL Query Blocks and Variables . DQL Search

DQL Query Blocks and Variables

This module shows you how to build more powerful queries with multiple query blocks and query variables.

Module Breakdown

5.1. Multiple Named Query Blocks 5.2. Query Variables 5.3. Query Variables in a child block 5.4. Query Variables in another query block I 5.5. Query Variables in another query block II 5.6. Exercise: Query Variables linking queries 5.7. Value variables - min and max 5.8. Exercise : Value variables - sum and avg 5.9. Value variables: filtering and ordering 5.10. Value variables: math functions 5.11. Exercise : Latest Movies 5.12. GroupBy 5.13. Congratulations!
Endpoint: /query
Dgraph: http://localhost:8080
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Response

5.3 Query Variables in a child block