feat: Create db_engine_spec ibmi.py

superset/db_engine_specs/ibmi.py

@@ -0,0 +1,53 @@
+# 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 superset.constants import TimeGrain
+from superset.db_engine_specs.base import BaseEngineSpec, LimitMethod
+
+
+class IBMiEngineSpec(BaseEngineSpec):
+    engine = "ibmi"
+    engine_name = "IBM Db2 for i"
+    limit_method = LimitMethod.WRAP_SQL
+    force_column_alias_quotes = True
+    max_column_name_length = 128
+
+    _time_grain_expressions = {
+        None: "{col}",
+        TimeGrain.SECOND: "CAST({col} as TIMESTAMP) - MICROSECOND({col}) MICROSECONDS",
+        TimeGrain.MINUTE: "CAST({col} as TIMESTAMP)"
+        " - SECOND({col}) SECONDS"
+        " - MICROSECOND({col}) MICROSECONDS",
+        TimeGrain.HOUR: "CAST({col} as TIMESTAMP)"
+        " - MINUTE({col}) MINUTES"
+        " - SECOND({col}) SECONDS"
+        " - MICROSECOND({col}) MICROSECONDS ",
+        TimeGrain.DAY: "CAST({col} as TIMESTAMP)"
+        " - HOUR({col}) HOURS"
+        " - MINUTE({col}) MINUTES"
+        " - SECOND({col}) SECONDS"
+        " - MICROSECOND({col}) MICROSECONDS",
+        TimeGrain.WEEK: "{col} - (DAYOFWEEK({col})) DAYS",
+        TimeGrain.MONTH: "{col} - (DAY({col})-1) DAYS",
+        TimeGrain.QUARTER: "{col} - (DAY({col})-1) DAYS"
+        " - (MONTH({col})-1) MONTHS"
+        " + ((QUARTER({col})-1) * 3) MONTHS",
+        TimeGrain.YEAR: "{col} - (DAY({col})-1) DAYS - (MONTH({col})-1) MONTHS",
+    }
+
+    @classmethod
+    def epoch_to_dttm(cls) -> str:
+        return "(DAYS({col}) - DAYS('1970-01-01')) * 86400 + MIDNIGHT_SECONDS({col})"