uqa_sql/semantics/rules/
binding.rs

1//
2// Unified Query Algebra
3//
4// Copyright (c) 2023-2026 Cognica, Inc.
5//
6
7//! OLD/NEW value binding for set-oriented rewrite-rule actions.
8
9use crate::{
10    ast::Expr,
11    plpgsql::{ResolvedVariable, VariableResolver},
12    ResultRow as Document, SQLError,
13};
14use std::collections::BTreeMap;
15use uqa_core::{DocId, Value};
16
17/// Logical OLD/NEW values used by rule action binding. Physical origins and source contexts stay in the executor.
18pub trait RuleRowValues {
19    fn old_row(&self) -> Option<&Document>;
20    fn new_row(&self) -> Option<&Document>;
21    fn old_doc_id(&self) -> Option<DocId>;
22    fn new_doc_id(&self) -> Option<DocId>;
23}
24
25mod actions;
26pub use actions::{bind_insert_values_action, bind_set_oriented_action, BoundSetOrientedAction};
27
28pub struct RuleColumnMetadata {
29    pub ty: crate::ast::ColumnType,
30    pub uses_document_id: bool,
31    pub position: usize,
32}
33
34pub(super) struct RuntimeRuleResolver<'a> {
35    pub(super) old: Option<&'a Document>,
36    pub(super) new: Option<&'a Document>,
37    pub(super) old_doc_id: Option<DocId>,
38    pub(super) new_doc_id: Option<DocId>,
39    pub(super) columns: &'a BTreeMap<String, RuleColumnMetadata>,
40}
41
42impl RuntimeRuleResolver<'_> {
43    pub(super) fn record_field(
44        &self,
45        record: Option<&Document>,
46        doc_id: Option<DocId>,
47        column: &str,
48    ) -> Result<ResolvedVariable, SQLError> {
49        let metadata = self
50            .columns
51            .get(column)
52            .ok_or_else(|| SQLError::UnknownColumn(column.to_string()))?;
53        let value = if let Some(value) = record.and_then(|record| record.get(column).cloned()) {
54            value
55        } else if metadata.uses_document_id {
56            doc_id
57                .map(i64::try_from)
58                .transpose()
59                .map_err(|_| {
60                    SQLError::TypeMismatch("document id exceeds PostgreSQL bigint".into())
61                })?
62                .map_or(Value::Null, Value::Int)
63        } else {
64            Value::Null
65        };
66        Ok(ResolvedVariable {
67            value,
68            declared_type: Some(metadata.ty.sql_name()),
69        })
70    }
71
72    pub(super) fn record(
73        &self,
74        record: Option<&Document>,
75        doc_id: Option<DocId>,
76    ) -> Result<ResolvedVariable, SQLError> {
77        let mut columns = self.columns.iter().collect::<Vec<_>>();
78        columns.sort_by_key(|(_, metadata)| metadata.position);
79        let fields = columns
80            .into_iter()
81            .map(|(column, _)| {
82                self.record_field(record, doc_id, column)
83                    .map(|field| (column.clone(), field.value))
84            })
85            .collect::<Result<Vec<_>, _>>()?;
86        Ok(ResolvedVariable::untyped(Value::Record(fields)))
87    }
88}
89
90impl VariableResolver for RuntimeRuleResolver<'_> {
91    fn resolve_name(&mut self, name: &str) -> Result<Option<ResolvedVariable>, SQLError> {
92        if name.eq_ignore_ascii_case("old") {
93            return self.record(self.old, self.old_doc_id).map(Some);
94        }
95        if name.eq_ignore_ascii_case("new") {
96            return self.record(self.new, self.new_doc_id).map(Some);
97        }
98        Ok(None)
99    }
100
101    fn resolve_qualified(
102        &mut self,
103        qualifier: &str,
104        column: &str,
105    ) -> Result<Option<ResolvedVariable>, SQLError> {
106        if qualifier.eq_ignore_ascii_case("old") {
107            return self
108                .record_field(self.old, self.old_doc_id, column)
109                .map(Some);
110        }
111        if qualifier.eq_ignore_ascii_case("new") {
112            return self
113                .record_field(self.new, self.new_doc_id, column)
114                .map(Some);
115        }
116        Ok(None)
117    }
118
119    fn resolve_param(&mut self, _index: usize) -> Result<Option<ResolvedVariable>, SQLError> {
120        Ok(None)
121    }
122
123    fn rewrite_qualified_whole_row(&mut self, qualifier: &str) -> Result<Option<Expr>, SQLError> {
124        Ok(self
125            .resolve_name(qualifier)?
126            .map(|record| Expr::Literal(record.value)))
127    }
128}
uqa_sql/semantics/rules/binding.rs

uqa_sql/semantics/rules/
binding.rs
