[GitHub] [airflow] kaxil commented on a change in pull request #13281: Add How-To guide for PostgresOperator

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kaxil commented on a change in pull request #13281:
URL: https://github.com/apache/airflow/pull/13281#discussion_r552509538



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File path: docs/apache-airflow-providers-postgres/operators/postgres_operator_howto_guide.rst
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@@ -0,0 +1,243 @@
+ .. 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.
+
+How-to Guide for PostgresOperator
+=================================
+
+Introduction
+------------
+
+Apache Airflow has a robust trove of operators that can be used to implement the various tasks that make up your
+workflow. Airflow is essentially a graph (Directed Acyclic Graph) made up of tasks (nodes) and dependencies (edges).
+
+A task defined or implemented by a operator is a unit of work in your data pipeline.
+
+The purpose of Postgres Operator is to define tasks involving interactions with the PostgreSQL database.
+ In ``Airflow-2.0``, the ``PostgresOperator`` class resides at ``airflow.providers.postgres.operator.postgres``.
+
+Under the hood, the ``PostgresOperator`` class delegates its heavy lifting to the ``PostgresHook`` class.
+
+Common Database Operations with PostgresOperator
+------------------------------------------------
+
+To use the postgres operator to carry out SQL request, two parameters are required: ``sql`` and ``postgres_conn_id``.
+These two parameters are eventually fed to the postgres hook object that interacts directly with the postgres database.
+
+Creating a Postgres database table
+----------------------------------
+
+The code snippets below are based on Airflow-2.0
+
+.. code-block:: python
+
+    import datetime
+    from airflow import DAG
+    from airflow.providers.postgres.operators.postgres import PostgresOperator
+
+
+    default_args = {
+                    "start_date": datetime.datetime(2020, 2, 2),
+                    "owner": "airflow"
+                    }
+
+
+    with DAG(dag_id="postgres_operator_dag", schedule_interval="@once", default_args=default_args, catchup=False) as dag:
+        create_pet_table = PostgresOperator(
+                                            "create_pet_table",
+                                            postgres_conn_id = "postgres_default",
+                                            sql = """
+                                            CREATE TABLE IF NOT EXISTS pet (
+                                                  pet_id SERIAL PRIMARY KEY,
+                                                  name VARCHAR NOT NULL,
+                                                  pet_type VARCHAR NOT NULL,
+                                                  birth_date DATE NOT NULL,
+                                                  OWNER VARCHAR NOT NULL);
+                                                  """
+                                            )

Review comment:
       ```suggestion
       with DAG(dag_id="postgres_operator_dag", schedule_interval="@once", default_args=default_args, catchup=False) as dag:
       create_pet_table = PostgresOperator(
           task_id="create_pet_table",
           postgres_conn_id = "postgres_default",
           sql = """
           CREATE TABLE IF NOT EXISTS pet (
                 pet_id SERIAL PRIMARY KEY,
                 name VARCHAR NOT NULL,
                 pet_type VARCHAR NOT NULL,
                 birth_date DATE NOT NULL,
                 OWNER VARCHAR NOT NULL);
                 """
       )
           )
   ```




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