sqlglot.optimizer.normalize_identifiers

 1from sqlglot import exp
 2from sqlglot._typing import E
 3from sqlglot.dialects.dialect import RESOLVES_IDENTIFIERS_AS_UPPERCASE, DialectType
 4
 5
 6def normalize_identifiers(expression: E, dialect: DialectType = None) -> E:
 7    """
 8    Normalize all unquoted identifiers to either lower or upper case, depending on
 9    the dialect. This essentially makes those identifiers case-insensitive.
10
11    Example:
12        >>> import sqlglot
13        >>> expression = sqlglot.parse_one('SELECT Bar.A AS A FROM "Foo".Bar')
14        >>> normalize_identifiers(expression).sql()
15        'SELECT bar.a AS a FROM "Foo".bar'
16
17    Args:
18        expression: The expression to transform.
19        dialect: The dialect to use in order to decide how to normalize identifiers.
20
21    Returns:
22        The transformed expression.
23    """
24    return expression.transform(_normalize, dialect, copy=False)
25
26
27def _normalize(node: exp.Expression, dialect: DialectType = None) -> exp.Expression:
28    if isinstance(node, exp.Identifier) and not node.quoted:
29        node.set(
30            "this",
31            node.this.upper()
32            if dialect in RESOLVES_IDENTIFIERS_AS_UPPERCASE
33            else node.this.lower(),
34        )
35
36    return node