surrealdb_core/sql/statements/

relate.rs

use crate::ctx::{Context, MutableContext};
use crate::dbs::{Iterable, Iterator, Options, Statement};
use crate::doc::CursorDoc;
use crate::err::Error;
use crate::sql::{Data, Output, Timeout, Value};
use derive::Store;
use reblessive::tree::Stk;
use revision::revisioned;
use serde::{Deserialize, Serialize};
use std::fmt;

#[revisioned(revision = 2)]
#[derive(Clone, Debug, Default, Eq, PartialEq, PartialOrd, Serialize, Deserialize, Store, Hash)]
#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
#[non_exhaustive]
pub struct RelateStatement {
	#[revision(start = 2)]
	pub only: bool,
	pub kind: Value,
	pub from: Value,
	pub with: Value,
	pub uniq: bool,
	pub data: Option<Data>,
	pub output: Option<Output>,
	pub timeout: Option<Timeout>,
	pub parallel: bool,
}

impl RelateStatement {
	/// Check if we require a writeable transaction
	pub(crate) fn writeable(&self) -> bool {
		true
	}
	/// Process this type returning a computed simple Value
	pub(crate) async fn compute(
		&self,
		stk: &mut Stk,
		ctx: &Context,
		opt: &Options,
		doc: Option<&CursorDoc>,
	) -> Result<Value, Error> {
		// Valid options?
		opt.valid_for_db()?;
		// Create a new iterator
		let mut i = Iterator::new();
		// Ensure futures are stored
		let opt = &opt.new_with_futures(false);
		// Check if there is a timeout
		let ctx = match self.timeout.as_ref() {
			Some(timeout) => {
				let mut ctx = MutableContext::new(ctx);
				ctx.add_timeout(*timeout.0)?;
				ctx.freeze()
			}
			None => ctx.clone(),
		};
		// Loop over the from targets
		let from = {
			let mut out = Vec::new();
			match self.from.compute(stk, &ctx, opt, doc).await? {
				Value::Thing(v) => out.push(v),
				Value::Array(v) => {
					for v in v {
						match v {
							Value::Thing(v) => out.push(v),
							Value::Object(v) => match v.rid() {
								Some(v) => out.push(v),
								_ => {
									return Err(Error::RelateStatementIn {
										value: v.to_string(),
									})
								}
							},
							v => {
								return Err(Error::RelateStatementIn {
									value: v.to_string(),
								})
							}
						}
					}
				}
				Value::Object(v) => match v.rid() {
					Some(v) => out.push(v),
					None => {
						return Err(Error::RelateStatementIn {
							value: v.to_string(),
						})
					}
				},
				v => {
					return Err(Error::RelateStatementIn {
						value: v.to_string(),
					})
				}
			};
			// }
			out
		};
		// Loop over the with targets
		let with = {
			let mut out = Vec::new();
			match self.with.compute(stk, &ctx, opt, doc).await? {
				Value::Thing(v) => out.push(v),
				Value::Array(v) => {
					for v in v {
						match v {
							Value::Thing(v) => out.push(v),
							Value::Object(v) => match v.rid() {
								Some(v) => out.push(v),
								None => {
									return Err(Error::RelateStatementId {
										value: v.to_string(),
									})
								}
							},
							v => {
								return Err(Error::RelateStatementId {
									value: v.to_string(),
								})
							}
						}
					}
				}
				Value::Object(v) => match v.rid() {
					Some(v) => out.push(v),
					None => {
						return Err(Error::RelateStatementId {
							value: v.to_string(),
						})
					}
				},
				v => {
					return Err(Error::RelateStatementId {
						value: v.to_string(),
					})
				}
			};
			out
		};
		//
		for f in from.iter() {
			for w in with.iter() {
				let f = f.clone();
				let w = w.clone();
				match &self.kind.compute(stk, &ctx, opt, doc).await? {
					// The relation has a specific record id
					Value::Thing(id) => i.ingest(Iterable::Relatable(f, id.to_owned(), w, None)),
					// The relation does not have a specific record id
					Value::Table(tb) => match &self.data {
						// There is a data clause so check for a record id
						Some(data) => {
							let id = match data.rid(stk, &ctx, opt).await? {
								Some(id) => id.generate(tb, false)?,
								None => tb.generate(),
							};
							i.ingest(Iterable::Relatable(f, id, w, None))
						}
						// There is no data clause so create a record id
						None => i.ingest(Iterable::Relatable(f, tb.generate(), w, None)),
					},
					// The relation can not be any other type
					v => {
						return Err(Error::RelateStatementOut {
							value: v.to_string(),
						})
					}
				};
			}
		}
		// Assign the statement
		let stm = Statement::from(self);
		// Process the statement
		let res = i.output(stk, &ctx, opt, &stm).await?;
		// Catch statement timeout
		if ctx.is_timedout() {
			return Err(Error::QueryTimedout);
		}
		// Output the results
		match res {
			// This is a single record result
			Value::Array(mut a) if self.only => match a.len() {
				// There was exactly one result
				1 => Ok(a.remove(0)),
				// There were no results
				_ => Err(Error::SingleOnlyOutput),
			},
			// This is standard query result
			v => Ok(v),
		}
	}
}

impl fmt::Display for RelateStatement {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		write!(f, "RELATE")?;
		if self.only {
			f.write_str(" ONLY")?
		}
		write!(f, " {} -> {} -> {}", self.from, self.kind, self.with)?;
		if self.uniq {
			f.write_str(" UNIQUE")?
		}
		if let Some(ref v) = self.data {
			write!(f, " {v}")?
		}
		if let Some(ref v) = self.output {
			write!(f, " {v}")?
		}
		if let Some(ref v) = self.timeout {
			write!(f, " {v}")?
		}
		if self.parallel {
			f.write_str(" PARALLEL")?
		}
		Ok(())
	}
}