uqa_sql/semantics/
referential.rs

1//
2// Unified Query Algebra
3//
4// Copyright (c) 2023-2026 Cognica, Inc.
5//
6
7//! Foreign-key action discovery across partition and inheritance metadata.
8use crate::{ast::ForeignKey, SQLError};
9
10pub trait ReferentialCatalog {
11    fn session_replication_role_is_replica(&self) -> bool;
12    fn hierarchy_ancestor_tables(&self, table: &str) -> Result<Vec<String>, SQLError>;
13    fn try_referrers_to(&self, table: &str) -> Result<Vec<(String, ForeignKey)>, String>;
14    fn partition_hierarchy_root(&self, table: &str) -> Result<Option<String>, SQLError>;
15}
16use crate::catalog::errors::dml_storage_error;
17
18pub fn referrers_to_for_actions(
19    catalog: &dyn ReferentialCatalog,
20    table: &str,
21) -> Result<Vec<(String, ForeignKey)>, SQLError> {
22    if catalog.session_replication_role_is_replica() {
23        return Ok(Vec::new());
24    }
25    let mut output = Vec::new();
26    for target in catalog.hierarchy_ancestor_tables(table)? {
27        let referrers = catalog
28            .try_referrers_to(&target)
29            .map_err(|err| dml_storage_error("foreign-key lookup", err))?;
30        for (declaring_table, foreign_key) in referrers {
31            let referencing_table = catalog
32                .partition_hierarchy_root(&declaring_table)?
33                .unwrap_or(declaring_table);
34            if output.iter().any(|(existing_table, existing_key)| {
35                existing_table == &referencing_table
36                    && foreign_keys_equivalent(existing_key, &foreign_key)
37            }) {
38                continue;
39            }
40            output.push((referencing_table, foreign_key));
41        }
42    }
43    Ok(output)
44}
45
46fn foreign_keys_equivalent(left: &ForeignKey, right: &ForeignKey) -> bool {
47    left.name == right.name
48        && left.local_columns == right.local_columns
49        && left.ref_table == right.ref_table
50        && left.ref_columns == right.ref_columns
51        && left.on_update == right.on_update
52        && left.on_delete == right.on_delete
53        && left.on_delete_set_columns == right.on_delete_set_columns
54        && left.match_type == right.match_type
55        && left.enforced == right.enforced
56}
uqa_sql/semantics/referential.rs

uqa_sql/semantics/
referential.rs
