Schema/Metadata API Reference: Remote Relationships¶

Table of contents

Introduction
create_remote_relationship
update_remote_relationship
delete_remote_relationship

Introduction¶

Remote Relationships allow you to join tables with remote schemas.

create_remote_relationship¶

create_remote_relationship is used to create a new remote relationship with an existing remote schema.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
   "type":"create_remote_relationship",
   "args":{
      "name": "sample_remote_relationship",
      "table": "users",
      "hasura_fields": ["id"],
      "remote_schema": "my-remote-schema",
      "remote_field": {
        "messages": {
           "arguments": {
              "id":"$id"
           }
        }
      }
   }
}

Args syntax¶

Key	Required	Schema	Description
name	true	RemoteRelationshipName	Name of the remote relationship
table	true	QualifiedTable	Object with table name and schema
hasura_fields	true	[PGColumn]	Column(s) in the table that is used for joining with remote schema field. All join keys in `remote_field` must appear here.
remote_schema	true	RemoteSchemaName	Name of the remote schema to join with
remote_field	true	RemoteField	The schema tree ending at the field in remote schema which needs to be joined with.

update_remote_relationship¶

update_remote_relationship is used to update an existing remote relationship.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
  "type": "update_remote_relationship",
  "args": {
     "name": "sample_remote_relationship",
     "table": "users",
     "hasura_fields": ["id"],
     "remote_schema": "my-remote-schema",
     "remote_field": {
       "posts": {
          "arguments": {
             "id": "$id",
             "likes": {
                "lte":"1000"
             }
          }
       }
     }
  }
}

Args syntax¶

Key	Required	Schema	Description
name	true	RemoteRelationshipName	Name of the remote relationship
table	true	QualifiedTable	Object with table name and schema
hasura_fields	true	[PGColumn]	Column(s) in the table that is used for joining with remote schema field. All join keys in `remote_field` must appear here.
remote_schema	true	RemoteSchemaName	Name of the remote schema to join with
remote_field	true	RemoteField	The schema tree ending at the field in remote schema which needs to be joined with.

delete_remote_relationship¶

delete_remote_relationship is used to delete an existing remote relationship.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "delete_remote_relationship",
    "args" : {
       "table":{
          "name":"users",
          "schema":"public"
       },
       "name":"sample_remote_relationship"
    }
}

Args syntax¶

Key	Required	Schema	Description
table	true	QualifiedTable	Object with table name and schema
name	true	RemoteRelationshipName	Name of the remote relationship

RemoteRelationshipName¶

String

RemoteField¶

{
   FieldName: {
     "arguments": InputArguments
     "field": RemoteField  # optional
   }
}

RemoteField is a recursive tree structure that points to the field in the remote schema that needs to be joined with. It is recursive because the remote field maybe nested deeply in the remote schema.

Examples:

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
   "message": {
      "arguments":{
         "message_id":"$id"
       }
   }
}

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
   "messages": {
      "arguments": {
         "limit": 100
      },
      "field": {
        "private": {
          "arguments": {
             "id" : "$id"
          }
        }
      }
   }
}

InputArguments¶

{
  InputField : $PGColumn | Scalar
}

Table columns can be referred by prefixing $ e.g $id.

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