Fix regex check for column name

target_snowflake/snowflake.py

@@ -526,7 +526,7 @@ def transform():
                 row = next(rows_iter)
 
                 with io.StringIO() as out:
-                    writer = csv.DictWriter(out, csv_headers)
+                    writer = csv.DictWriter(out, csv_headers, quoting=csv.QUOTE_NONNUMERIC)
                     writer.writerow(row)
                     return out.getvalue()
             except StopIteration:

target_snowflake/sql.py

@@ -21,11 +21,11 @@ def valid_identifier(x):
             IDENTIFIER_FIELD_LENGTH,
             len(x),
             x))
-
-    if not re.match(r'^[a-zA-Z_]\w+$', x):
+    
+    if not re.match(r'^[a-zA-Z_](\w+)?$', x):
         raise SQLError(
-            'Identifier must only contain alphanumerics, or underscores, and start with alphas. Got `{}` for `{}`'.format(
-                re.findall(r'[^0-9]', '1234a567')[0],
+            'Identifier must only contain alphanumerics, or underscores, and start with alphas. Found `{}` from name `{}`'.format(
+                re.findall(r'[^0-9a-zA-Z_]', x),
                 x
             ))
 

tests/fixtures.py

@@ -221,7 +221,6 @@ def generate_record(self):
             'adoption': adoption
         }
 
-
 class InvalidCatStream(CatStream):
     def generate_record(self):
         record = CatStream.generate_record(self)
@@ -433,6 +432,29 @@ def generate_record(self):
         }
 
 
+SINGLE_CHAR_SCHEMA = {
+    'type': 'SCHEMA',
+    'stream': 'root',
+    'schema': {
+        'additionalProperties': False,
+        'properties': {
+            'x': {
+                'type': 'integer'
+            }
+        }
+    },
+    'key_properties': []
+}
+
+class SingleCharStream(FakeStream):
+    stream = 'root'
+    schema = SINGLE_CHAR_SCHEMA
+
+    def generate_record(self):
+        return {
+            'x': random.randint(-314159265359, 314159265359)
+        }
+
 
 def clear_schema():
     with connect(**TEST_DB) as conn:

tests/test_target_snowflake.py

@@ -4,7 +4,7 @@
 from psycopg2 import sql
 import pytest
 
-from fixtures import CatStream, CONFIG, db_prep, MultiTypeStream, NestedStream, S3_CONFIG, TEST_DB
+from fixtures import CatStream, CONFIG, db_prep, MultiTypeStream, NestedStream, SingleCharStream, S3_CONFIG, TEST_DB
 from target_postgres import singer_stream
 from target_postgres.target_tools import TargetError
 
@@ -652,6 +652,40 @@ def test_loading__multi_types_columns(db_prep):
             assert stream_count == len([x for x in persisted_records if isinstance(x[0], float)])
 
 
+def test_loading__single_char_columns(db_prep):
+    stream_count = 50
+    main(CONFIG, input_stream=SingleCharStream(stream_count))
+
+    with connect(**TEST_DB) as conn:
+        with conn.cursor() as cur:
+            assert_columns_equal(cur,
+                                 'ROOT',
+                                 {
+                                     ('_SDC_PRIMARY_KEY', 'TEXT', 'NO'),
+                                     ('_SDC_BATCHED_AT', 'TIMESTAMP_TZ', 'YES'),
+                                     ('_SDC_RECEIVED_AT', 'TIMESTAMP_TZ', 'YES'),
+                                     ('_SDC_SEQUENCE', 'NUMBER', 'YES'),
+                                     ('_SDC_TABLE_VERSION', 'NUMBER', 'YES'),
+                                     ('_SDC_TARGET_SNOWFLAKE_CREATE_TABLE_PLACEHOLDER', 'BOOLEAN', 'YES'),
+                                     ('X', 'NUMBER', 'YES')
+                                 })
+
+            cur.execute('''
+                SELECT {} FROM {}.{}.{}
+            '''.format(
+                sql.identifier('X'),
+                sql.identifier(CONFIG['snowflake_database']),
+                sql.identifier(CONFIG['snowflake_schema']),
+                sql.identifier('ROOT')
+            ))
+            persisted_records = cur.fetchall()
+
+            ## Assert that the column is has migrated data
+            assert stream_count == len(persisted_records)
+            assert stream_count == len([x for x in persisted_records if isinstance(x[0], float)])
+
+
+
 def test_upsert(db_prep):
     stream = CatStream(100)
     main(CONFIG, input_stream=stream)