Revert automatic set of sequence start to 1

The :class:`.Sequence` construct restores itself to the DDL behavior it
had prior to the 1.4 series, where creating a :class:`.Sequence` with
no additional arguments will emit a simple ``CREATE SEQUENCE`` instruction
**without** any additional parameters for "start value".   For most backends,
this is how things worked previously in any case; **however**, for
MS SQL Server, the default value on this database is
``-2**63``; to prevent this generally impractical default
from taking effect on SQL Server, the :paramref:`.Sequence.start` parameter
should be provided.   As usage of :class:`.Sequence` is unusual
for SQL Server which for many years has standardized on ``IDENTITY``,
it is hoped that this change has minimal impact.

Fixes: #7211
Change-Id: I1207ea10c8cb1528a1519a0fb3581d9621c27b31

1 files changed, 18 insertions, 2 deletions

diff --git a/test/dialect/mssql/test_sequence.py b/test/dialect/mssql/test_sequence.py
index 5afe9c075..c03607e7a 100644
--- a/test/dialect/mssql/test_sequence.py
+++ b/test/dialect/mssql/test_sequence.py
@@ -8,8 +8,10 @@ from sqlalchemy import select
 from sqlalchemy import Sequence
 from sqlalchemy import String
 from sqlalchemy import Table
+from sqlalchemy.testing import config
 from sqlalchemy.testing import eq_
 from sqlalchemy.testing import fixtures
+from sqlalchemy.testing.provision import normalize_sequence
 
 
 class SequenceTest(fixtures.TablesTest):
@@ -24,6 +26,18 @@ class SequenceTest(fixtures.TablesTest):
             Column(
                 "id", Integer, default=Sequence("int_seq", data_type=Integer())
             ),
+            Column(
+                "id_provision",
+                Integer,
+                default=normalize_sequence(
+                    config, Sequence("id_provision", data_type=Integer())
+                ),
+            ),
+            Column(
+                "id_start",
+                Integer,
+                default=Sequence("id_start", data_type=Integer(), start=42),
+            ),
             Column("txt", String(50)),
         )
 
@@ -56,8 +70,10 @@ class SequenceTest(fixtures.TablesTest):
     def test_int_seq(self, connection):
         t = self.tables.int_seq_t
         connection.execute(t.insert().values({"txt": "int_seq test"}))
-        result = connection.scalar(select(t.c.id))
-        eq_(result, 1)
+        result = connection.execute(select(t)).first()
+        eq_(result.id, -(2**31))
+        eq_(result.id_provision, 1)
+        eq_(result.id_start, 42)
 
     def test_bigint_seq(self, connection):
         t = self.tables.bigint_seq_t