62 lines
1.9 KiB
Python
62 lines
1.9 KiB
Python
from __future__ import annotations
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import typing as t
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from sqlglot import exp
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from sqlglot._typing import E
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from sqlglot.dialects.dialect import Dialect, DialectType
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@t.overload
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def normalize_identifiers(expression: E, dialect: DialectType = None) -> E:
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...
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@t.overload
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def normalize_identifiers(expression: str, dialect: DialectType = None) -> exp.Expression:
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...
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def normalize_identifiers(expression, dialect=None):
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"""
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Normalize all unquoted identifiers to either lower or upper case, depending
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on the dialect. This essentially makes those identifiers case-insensitive.
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It's possible to make this a no-op by adding a special comment next to the
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identifier of interest:
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SELECT a /* sqlglot.meta case_sensitive */ FROM table
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In this example, the identifier `a` will not be normalized.
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Note:
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Some dialects (e.g. BigQuery) treat identifiers as case-insensitive even
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when they're quoted, so in these cases all identifiers are normalized.
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Example:
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>>> import sqlglot
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>>> expression = sqlglot.parse_one('SELECT Bar.A AS A FROM "Foo".Bar')
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>>> normalize_identifiers(expression).sql()
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'SELECT bar.a AS a FROM "Foo".bar'
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>>> normalize_identifiers("foo", dialect="snowflake").sql(dialect="snowflake")
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'FOO'
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Args:
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expression: The expression to transform.
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dialect: The dialect to use in order to decide how to normalize identifiers.
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Returns:
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The transformed expression.
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"""
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if isinstance(expression, str):
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expression = exp.parse_identifier(expression, dialect=dialect)
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dialect = Dialect.get_or_raise(dialect)
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def _normalize(node: E) -> E:
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if not node.meta.get("case_sensitive"):
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exp.replace_children(node, _normalize)
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node = dialect.normalize_identifier(node)
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return node
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return _normalize(expression)
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