koron_query_parser/
support.rs

1use sqlparser::ast;
2
3use crate::{error::ParseError, internal, malformed_query, query_metadata::FromClauseIdentifier};
4
5//recursively removes outer parenthesis
6pub(crate) fn remove_outer_parens(expr: &ast::Expr) -> &ast::Expr {
7    match expr {
8        ast::Expr::Nested(inner) => remove_outer_parens(inner),
9        _ => expr,
10    }
11}
12
13//extract column name from name_parts and if table/schema/db identifier are there, checks if it corresponds to FROM clause
14pub(crate) fn extract_qualified_column(
15    from_clause_identifier: FromClauseIdentifier<'_>,
16    compound_identifier: &ast::Expr,
17    name_parts: &[ast::Ident],
18) -> Result<String, ParseError> {
19    let unknown_column = || {
20        Err(malformed_query!(format!(
21                "the {compound_identifier} column is not part of the table that's listed in the FROM clause ({from_clause_identifier}).",
22            )))
23    };
24
25    let mut name_parts = name_parts.iter();
26
27    let column = name_parts.next_back().ok_or_else(|| {
28        internal!("found empty column name (CompoundIdentifier) in query AST.".to_string())
29    })?;
30    let column = case_fold_identifier(column);
31
32    if let Some(table) = name_parts.next_back() {
33        let schema = name_parts.next_back();
34        let db = name_parts.next_back();
35        if !from_clause_identifier.matches(db, schema, table) {
36            return unknown_column();
37        }
38    }
39    if name_parts.count() > 0 {
40        return Err(internal!(format!(
41            "found too many ident in column name (i.e., {compound_identifier})."
42        )));
43    }
44
45    Ok(column)
46}
47
48pub(crate) fn case_fold_identifier(ident: &ast::Ident) -> String {
49    // Fold unquoted identifiers to lowercase, like PostgreSQL does (see
50    // https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS).
51    let ast::Ident { value, quote_style } = ident;
52    if quote_style.is_none() {
53        value.to_ascii_lowercase()
54    } else {
55        value.to_string()
56    }
57}
koron_query_parser/support.rs

koron_query_parser/
support.rs
