Add support for database engine SAP Hana (#8411)

* Add support for database engine SAP Hana

* Support hana services

Increase time, minute, and second

* Fix hana return string

* Fix formatting errors

docs/index.rst

@@ -123,6 +123,7 @@ The following RDBMS are currently supported:
 - `SQL Server <https://www.microsoft.com/en-us/sql-server/>`_
 - `Teradata <https://www.teradata.com/>`_
 - `Vertica <https://www.vertica.com/>`_
+- `Hana <https://www.sap.com/products/hana.html>`_
 
 Other database engines with a proper DB-API driver and SQLAlchemy dialect should
 be supported as well.

docs/installation.rst

@@ -404,12 +404,24 @@ Here's a list of some of the recommended packages.
 | Vertica          | ``pip install                         |  ``vertica+vertica_python://``                  |
 |                  | sqlalchemy-vertica-python``           |                                                 |
 +------------------+---------------------------------------+-------------------------------------------------+
+| Hana             | ``pip install hdbcli sqlalchemy-hana``|  ``hana://``                                    |
+|                  | or ``pip install superset[hana]``     |                                                 |
++------------------+---------------------------------------+-------------------------------------------------+
+
 
 Note that many other databases are supported, the main criteria being the
 existence of a functional SqlAlchemy dialect and Python driver. Googling
 the keyword ``sqlalchemy`` in addition of a keyword that describes the
 database you want to connect to should get you to the right place.
 
+Hana
+------------
+
+The connection string for Hana looks like this ::
+
+    hana://{username}:{password}@{host}:{port}
+
+
 (AWS) Athena
 ------------
 

setup.py

@@ -117,6 +117,7 @@ setup(
         "presto": ["pyhive[presto]>=0.4.0"],
         "elasticsearch": ["elasticsearch-dbapi>=0.1.0, <0.2.0"],
         "druid": ["pydruid==0.5.7", "requests==2.22.0"],
+        "hana": ["hdbcli==2.4.162", "sqlalchemy_hana==0.4.0"],
     },
     python_requires="~=3.6",
     author="Apache Software Foundation",

superset/db_engine_specs/hana.py

@@ -0,0 +1,50 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from datetime import datetime
+from typing import Optional
+
+from superset.db_engine_specs.base import LimitMethod
+from superset.db_engine_specs.postgres import PostgresBaseEngineSpec
+
+
+class HanaEngineSpec(PostgresBaseEngineSpec):
+    engine = "hana"
+    limit_method = LimitMethod.WRAP_SQL
+    force_column_alias_quotes = True
+    max_column_name_length = 30
+
+    _time_grain_functions = {
+        None: "{col}",
+        "PT1S": "TO_TIMESTAMP(SUBSTRING(TO_TIMESTAMP({col}),0,20))",
+        "PT1M": "TO_TIMESTAMP(SUBSTRING(TO_TIMESTAMP({col}),0,17) || '00')",
+        "PT1H": "TO_TIMESTAMP(SUBSTRING(TO_TIMESTAMP({col}),0,14) || '00:00')",
+        "P1D": "TO_DATE({col})",
+        "P1M": "TO_DATE(SUBSTRING(TO_DATE({col}),0,7)||'-01')",
+        "P0.25Y": "TO_DATE(SUBSTRING( \
+                   TO_DATE({col}), 0, 5)|| LPAD(CAST((CAST(SUBSTRING(QUARTER( \
+                   TO_DATE({col}), 1), 7, 1) as int)-1)*3 +1 as text),2,'0') ||'-01')",
+        "P1Y": "TO_DATE(YEAR({col})||'-01-01')",
+    }
+
+    @classmethod
+    def convert_dttm(cls, target_type: str, dttm: datetime) -> Optional[str]:
+        tt = target_type.upper()
+        if tt == "DATE":
+            return f"TO_DATE('{dttm.date().isoformat()}', 'YYYY-MM-DD')"
+        if tt == "TIMESTAMP":
+            return f"""TO_TIMESTAMP('{dttm.isoformat(timespec="microseconds")}', 'YYYY-MM-DD"T"HH24:MI:SS.ff6')"""  # pylint: disable=line-too-long
+        return None