Merge pull request #336 from datafold/fix_current_timestamp

Added tests for current_timestamp + fixes for some of the dbs

Author: erezsh

data_diff/sqeleton/databases/base.py

@@ -124,6 +124,8 @@ class BaseDialect(AbstractDialect):
     SUPPORTS_INDEXES = False
     TYPE_CLASSES: Dict[str, type] = {}
 
+    PLACEHOLDER_TABLE = None        # Used for Oracle
+
     def offset_limit(self, offset: Optional[int] = None, limit: Optional[int] = None):
         if offset:
             raise NotImplementedError("No support for OFFSET in query")
@@ -302,7 +304,9 @@ def query(self, sql_ast: Union[Expr, Generator], res_type: type = list):
             return int(res)
         elif res_type is datetime:
             res = _one(_one(res))
-            return res  # XXX parse timestamp?
+            if isinstance(res, str):
+                res = datetime.fromisoformat(res[:23])  # TODO use a better parsing method
+            return res
         elif res_type is tuple:
             assert len(res) == 1, (sql_code, res)
             return res[0]

data_diff/sqeleton/databases/clickhouse.py

@@ -155,6 +155,9 @@ def _parse_type_repr(self, type_repr: str) -> Optional[Type[ColType]]:
     def set_timezone_to_utc(self) -> str:
         raise NotImplementedError()
 
+    def current_timestamp(self) -> str:
+        return "now()"
+
 
 class Clickhouse(ThreadedDatabase):
     dialect = Dialect()

data_diff/sqeleton/databases/duckdb.py

@@ -111,6 +111,8 @@ def parse_type(
     def set_timezone_to_utc(self) -> str:
         return "SET GLOBAL TimeZone='UTC'"
 
+    def current_timestamp(self) -> str:
+        return "current_timestamp"
 
 class DuckDB(Database):
     dialect = Dialect()

data_diff/sqeleton/databases/oracle.py

@@ -86,6 +86,7 @@ class Dialect(BaseDialect, Mixin_Schema):
         "VARCHAR2": Text,
     }
     ROUNDS_ON_PREC_LOSS = True
+    PLACEHOLDER_TABLE = "DUAL"
 
     def quote(self, s: str):
         return f'"{s}"'
@@ -152,6 +153,9 @@ def parse_type(
     def set_timezone_to_utc(self) -> str:
         return "ALTER SESSION SET TIME_ZONE = 'UTC'"
 
+    def current_timestamp(self) -> str:
+        return "LOCALTIMESTAMP"
+
 
 class Oracle(ThreadedDatabase):
     dialect = Dialect()

data_diff/sqeleton/databases/postgresql.py

@@ -90,6 +90,9 @@ def _convert_db_precision_to_digits(self, p: int) -> int:
     def set_timezone_to_utc(self) -> str:
         return "SET TIME ZONE 'UTC'"
 
+    def current_timestamp(self) -> str:
+        return "current_timestamp"
+
 
 class PostgreSQL(ThreadedDatabase):
     dialect = PostgresqlDialect()

data_diff/sqeleton/databases/presto.py

@@ -137,6 +137,8 @@ def parse_type(
     def set_timezone_to_utc(self) -> str:
         return "SET TIME ZONE '+00:00'"
 
+    def current_timestamp(self) -> str:
+        return "current_timestamp"
 
 class Presto(Database):
     dialect = Dialect()

data_diff/sqeleton/databases/vertica.py

@@ -144,6 +144,9 @@ def parse_type(
     def set_timezone_to_utc(self) -> str:
         return "SET TIME ZONE TO 'UTC'"
 
+    def current_timestamp(self) -> str:
+        return "current_timestamp(6)"
+
 
 class Vertica(ThreadedDatabase):
     dialect = Dialect()

data_diff/sqeleton/queries/__init__.py

@@ -18,6 +18,7 @@
     or_,
     leftjoin,
     rightjoin,
+    current_timestamp
 )
 from .ast_classes import Expr, ExprNode, Select, Count, BinOp, Explain, In, Code, Column
 from .extras import Checksum, NormalizeAsString, ApplyFuncAndNormalizeAsString

data_diff/sqeleton/queries/ast_classes.py

@@ -601,6 +601,9 @@ def compile(self, parent_c: Compiler) -> str:
 
         if self.table:
             select += " FROM " + c.compile(self.table)
+        elif c.dialect.PLACEHOLDER_TABLE:
+            select += f" FROM {c.dialect.PLACEHOLDER_TABLE}"
+
 
         if self.where_exprs:
             select += " WHERE " + " AND ".join(map(c.compile, self.where_exprs))

tests/sqeleton/test_database.py

@@ -1,10 +1,11 @@
 from typing import Callable, List
+from datetime import datetime
 import unittest
 
 from ..common import str_to_checksum, TEST_MYSQL_CONN_STRING
 from ..common import str_to_checksum, test_each_database_in_list, DiffTestCase, get_conn, random_table_suffix
 
-from data_diff.sqeleton.queries import table
+from data_diff.sqeleton.queries import table, current_timestamp
 
 from data_diff import databases as dbs
 from data_diff.databases import connect
@@ -63,3 +64,12 @@ def test_table_list(self):
 
         db.query(tbl.drop())
         assert not db.query(q)
+
+
+@test_each_database
+class TestQueries(unittest.TestCase):
+
+    def test_current_timestamp(self):
+        db = get_conn(self.db_cls)
+        res = db.query(current_timestamp(), datetime)
+        assert isinstance(res, datetime), (res, type(res))