Support multiple dotted sections in mssql schema names

Refined the logic used by the SQL Server dialect to interpret multi-part
schema names that contain many dots, to not actually lose any dots if the
name does not have bracking or quoting used, and additionally to support a
"dbname" token that has many parts including that it may have multiple,
independently-bracketed sections.

This fix addresses #5364 to some degree but probably does not
resolve it fully.

References: #5364
Fixes: #5366
Change-Id: I460cd74ce443efb35fb63b6864f00c6d81422688

1 files changed, 37 insertions, 0 deletions

diff --git a/test/dialect/mssql/test_compiler.py b/test/dialect/mssql/test_compiler.py
index b7a06c8e3..25af3240e 100644
--- a/test/dialect/mssql/test_compiler.py
+++ b/test/dialect/mssql/test_compiler.py
@@ -22,6 +22,7 @@ from sqlalchemy import union
 from sqlalchemy import UniqueConstraint
 from sqlalchemy import update
 from sqlalchemy.dialects import mssql
+from sqlalchemy.dialects.mssql import base as mssql_base
 from sqlalchemy.dialects.mssql import mxodbc
 from sqlalchemy.dialects.mssql.base import try_cast
 from sqlalchemy.sql import column
@@ -525,6 +526,42 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
             checkpositional=("bar",),
         )
 
+    def test_schema_many_tokens_one(self):
+        metadata = MetaData()
+        tbl = Table(
+            "test",
+            metadata,
+            Column("id", Integer, primary_key=True),
+            schema="abc.def.efg.hij",
+        )
+
+        # for now, we don't really know what the above means, at least
+        # don't lose the dot
+        self.assert_compile(
+            select([tbl]),
+            "SELECT [abc.def.efg].hij.test.id FROM [abc.def.efg].hij.test",
+        )
+
+        dbname, owner = mssql_base._schema_elements("abc.def.efg.hij")
+        eq_(dbname, "abc.def.efg")
+        assert not isinstance(dbname, quoted_name)
+        eq_(owner, "hij")
+
+    def test_schema_many_tokens_two(self):
+        metadata = MetaData()
+        tbl = Table(
+            "test",
+            metadata,
+            Column("id", Integer, primary_key=True),
+            schema="[abc].[def].[efg].[hij]",
+        )
+
+        self.assert_compile(
+            select([tbl]),
+            "SELECT [abc].[def].[efg].hij.test.id "
+            "FROM [abc].[def].[efg].hij.test",
+        )
+
     def test_force_schema_quoted_name_w_dot_case_insensitive(self):
         metadata = MetaData()
         tbl = Table(