queryRoot

QueryRoot is a concept used in database query processing to denote the top-level entry point of a query expression within an abstract syntax tree or execution plan. It usually represents the initial node from which the evaluation starts and from which other operations such as filtering, projection, joins, and aggregates descend.

In GraphQL, the term is often used to describe the root type for read operations. The GraphQL specification defines a root operation type called Query, which acts as the entry point for all read operations; fields on this type resolve to data. A schema may also define Mutation and Subscription root types, which represent write and real-time operations.

In query planning and optimization, the queryRoot node carries information such as the operation kind (select, insert, update), the data source, variables, and directives. The planner expands the root into a plan tree; the executor traverses the plan starting at the root.

In practice, queryRoot helps compose complex queries, unify access patterns across data sources, and support features like parameterized queries, access control, and optimization boundaries.

See also: abstract syntax tree, GraphQL, query planner, root node.