Refactor(schema): replace _ensure_table with exp.maybe_parse (#1709)

sqlglot/expressions.py

@@ -4575,6 +4575,7 @@ def maybe_parse(
     sql = str(sql_or_expression)
     if prefix:
         sql = f"{prefix} {sql}"
+
     return sqlglot.parse_one(sql, read=dialect, into=into, **opts)
 
 

sqlglot/schema.py

@@ -227,7 +227,7 @@ def add_table(
             dialect: the SQL dialect that will be used to parse `table` if it's a string.
         """
         normalized_table = self._normalize_table(
-            self._ensure_table(table, dialect=dialect), dialect=dialect
+            exp.maybe_parse(table, into=exp.Table, dialect=dialect), dialect=dialect
         )
         normalized_column_mapping = {
             self._normalize_name(key, dialect=dialect): value
@@ -250,7 +250,7 @@ def column_names(
         dialect: DialectType = None,
     ) -> t.List[str]:
         normalized_table = self._normalize_table(
-            self._ensure_table(table, dialect=dialect), dialect=dialect
+            exp.maybe_parse(table, into=exp.Table, dialect=dialect), dialect=dialect
         )
 
         schema = self.find(normalized_table)
@@ -270,7 +270,7 @@ def get_column_type(
         dialect: DialectType = None,
     ) -> exp.DataType:
         normalized_table = self._normalize_table(
-            self._ensure_table(table, dialect=dialect), dialect=dialect
+            exp.maybe_parse(table, into=exp.Table, dialect=dialect), dialect=dialect
         )
         normalized_column_name = self._normalize_name(
             column if isinstance(column, str) else column.this, dialect=dialect
@@ -345,19 +345,6 @@ def _depth(self) -> int:
         # The columns themselves are a mapping, but we don't want to include those
         return super()._depth() - 1
 
-    def _ensure_table(self, table: exp.Table | str, dialect: DialectType = None) -> exp.Table:
-        if isinstance(table, exp.Table):
-            return table
-
-        dialect = dialect or self.dialect
-        parsed_table = sqlglot.parse_one(table, read=dialect, into=exp.Table)
-
-        if not parsed_table:
-            in_dialect = f" in dialect {dialect}" if dialect else ""
-            raise SchemaError(f"Failed to parse table '{table}'{in_dialect}.")
-
-        return parsed_table
-
     def _to_data_type(self, schema_type: str, dialect: DialectType = None) -> exp.DataType:
         """
         Convert a type represented as a string to the corresponding `sqlglot.exp.DataType` object.