Struct FunctionField 

pub struct FunctionField {
    pub name: String,
    pub schema_name: String,
    pub function_name: String,
    pub returns: String,
    pub returns_table: (String, String),
    pub arguments: Vec<(String, String, bool)>,
    pub session_argument: Option<String>,
    pub volatile: bool,
    pub description: Option<String>,
}

A database function returning rows of a table, exposed as a root field.

A function that returns SETOF <table> answers the same question a table does, from a query somebody wrote in SQL rather than from the table directly. It filters, orders and pages like the table it returns, and its own arguments arrive under args so they cannot collide with those.

Where it appears follows from what PostgreSQL says it does: a function declared VOLATILE may write, so it is a mutation; one declared STABLE or IMMUTABLE may not, so it is a query. Nothing else is a safe place to draw that line – the alternative is trusting a name.

Fields

name: String

The field’s name, which is the function’s.

schema_name: String

Schema the function lives in.

function_name: String

The function’s own name, which the field is named after.

returns: String

The GraphQL type of the rows it returns.

returns_table: (String, String)

The table those rows belong to, as (schema, table).

arguments: Vec<(String, String, bool)>

Its arguments, as (name, PostgreSQL type, required). The session argument is not among them: the client does not supply it.

session_argument: Option<String>

The name of its session argument, if it has one.

Hasura’s convention: a hasura_session json parameter is filled from the caller’s session variables rather than taken from the request, so a function can read who is asking. Exposing it as an argument would let the caller name its own identity, which is the opposite of the point.

volatile: bool

Whether it may write, and so belongs on the mutation root.

description: Option<String>

Description from the function’s comment.

Trait Implementations

impl Clone for FunctionField

fn clone(&self) -> FunctionField

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FunctionField

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.