uqa_sql/binding/stored_columns/
statements.rs

1//
2// Unified Query Algebra
3//
4// Copyright (c) 2023-2026 Cognica, Inc.
5//
6
7//! Column dependencies of stored MERGE actions, including target assignments.
8
9use crate::ast::{MergeStmt, MergeWhen, RuleEvent};
10
11use super::{
12    action_returning_scope, ColumnBindingContext, ColumnBindingMode, ColumnScope, RelationIdentity,
13    RuleColumnDependency, SQLError, Statement, StoredColumnBinder, StoredColumnBindingContext,
14};
15
16pub fn rewrite_stored_statement_column(
17    catalog: StoredColumnBindingContext<'_>,
18    statement: &mut Statement,
19    relation: &RelationIdentity,
20    from: &str,
21    to: &str,
22) -> Result<bool, SQLError> {
23    let mode = ColumnBindingMode::Rename { relation, from, to };
24    let mut binder = StoredColumnBinder::new(catalog, mode);
25    binder.bind_statement(statement, &[], &ColumnBindingContext::default())?;
26    let shape_changed = binder.alias_shape_changed();
27    Ok(binder.finish().contains(&RuleColumnDependency {
28        relation: relation.clone(),
29        column: from.to_string(),
30    }) || shape_changed)
31}
32
33impl StoredColumnBinder<'_> {
34    pub(super) fn bind_merge(
35        &mut self,
36        merge: &mut MergeStmt,
37        outer: &[ColumnScope],
38        context: &ColumnBindingContext,
39    ) -> Result<(), SQLError> {
40        let context = self.bind_ctes(&mut merge.with, outer, context)?;
41        let target = self.table_scope(
42            &merge.target,
43            &merge.target_qualifier,
44            merge.target_alias.as_deref(),
45            &[],
46            None,
47            &ColumnBindingContext::default(),
48        )?;
49        let (local, scopes) =
50            self.bind_dml_source(Some(&mut merge.source), &target, outer, &context)?;
51        let dropped_targets =
52            crate::routines::merge_columns::dropped_stored_merge_targets(self.catalog.merge, merge);
53        self.bind_expr(&mut merge.join_condition, &scopes, &context)?;
54        for action in &mut merge.when_clauses {
55            let condition = match action {
56                MergeWhen::UpdateMatched {
57                    condition,
58                    assignments,
59                }
60                | MergeWhen::UpdateNotMatchedBySource {
61                    condition,
62                    assignments,
63                } => {
64                    for (column, expression) in assignments {
65                        if self.mode.is_rename() && !dropped_targets.contains(&column.column) {
66                            self.bind_target_name(&mut column.column, &target);
67                        }
68                        for expression in column.expressions_mut() {
69                            self.bind_expr(expression, &scopes, &context)?;
70                        }
71                        self.bind_expr(expression, &scopes, &context)?;
72                    }
73                    condition
74                }
75                MergeWhen::InsertNotMatched {
76                    condition,
77                    columns,
78                    values,
79                } => {
80                    if columns.is_empty() {
81                        *columns = target
82                            .output
83                            .iter()
84                            .take(values.len())
85                            .map(|column| column.current_name.clone().into())
86                            .collect();
87                    }
88                    for column in columns {
89                        if self.mode.is_rename() && !dropped_targets.contains(&column.column) {
90                            self.bind_target_name(&mut column.column, &target);
91                        }
92                        for expression in column.expressions_mut() {
93                            self.bind_expr(expression, &scopes, &context)?;
94                        }
95                    }
96                    for expression in values {
97                        self.bind_expr(expression, &scopes, &context)?;
98                    }
99                    condition
100                }
101                MergeWhen::DeleteMatched { condition }
102                | MergeWhen::DeleteNotMatchedBySource { condition }
103                | MergeWhen::NothingMatched { condition }
104                | MergeWhen::NothingNotMatched { condition }
105                | MergeWhen::NothingNotMatchedBySource { condition } => condition,
106            };
107            if let Some(condition) = condition {
108                self.bind_expr(condition, &scopes, &context)?;
109            }
110        }
111        if let ColumnBindingMode::Rename { relation, from, to } = self.mode {
112            if merge.target == relation.qualified_name() && !dropped_targets.contains(from) {
113                if let Some(binding) = merge.target_column_bindings.remove(from) {
114                    merge.target_column_bindings.insert(to.to_string(), binding);
115                }
116            }
117        }
118        let returning =
119            action_returning_scope(&local, &target, RuleEvent::Update, &merge.returning_aliases);
120        let mut scopes = vec![returning.clone()];
121        scopes.extend_from_slice(outer);
122        self.bind_projections(&mut merge.returning, Some(&returning), &scopes, &context)
123    }
124}
uqa_sql/binding/stored_columns/statements.rs

uqa_sql/binding/stored_columns/
statements.rs
