Demonstrating Use of Out-of-Schema Properties with Orator

2016_12_18_205220_create_table_examples.py

from orator.migrations import Migration

class CreateTableExamples(Migration):

    def up(self):
        """
        Run the migrations.
        """
        with self.schema.create('examples') as table:
            table.big_increments('id')
            table.char('name',255)
        pass

    def down(self):
        """
        Revert the migrations.
        """
        self.schema.drop_if_exists('hands')
        pass

example_model.py

from orator import Model

class Example(Model):
    # Exclude timestamps.
    __timestamps__ = []

    def __init__(self,c=None):
        super(Example, self).__init__()
        self.__name = "This world is so confusing from the inside!"  # Commenting this line will make saving possible.
        self.name = "Hello World!"
    
    def __str__(self):
        return self.name

    def __repr__(sself):
        return self.__name

orator.yml

# Define how orator's CLI should connect to the database.
databases:
  postgresql:
    driver: postgres
    host: localhost
    database: gist_examples

run_example.py

#!/usr/bin/env python3

# Configure the database connection, and make a connection.
config = {
    'postgresql': {
        'driver': 'postgres',
        'host': 'localhost',
        'database': 'gist_examples'
    }
}

from orator import DatabaseManager
db = DatabaseManager(config)

# Bind the Model base class to the database connection.
from orator import Model
Model.set_connection_resolver(db)

# Import the Example model class.
from example_model import Example

# Create an instance of the Example model class.
example = Example()
print("==> Here is my example: '{}'\n".format(example))

# Attempt to save the instance as a new record in the database.
# This generates an error because we defined a property that 
example.save()

setup_example.bash

#!/bin/bash

# Create the database if it does not already exist.
if psql -lqt | cut -d \| -f 1 | grep -qw "gist_examples"; then
    # Do nothing.
    echo "Database 'gist_examples' already exists."
else
    # Create the database, since it does not already exist.
    echo "Creating database 'gist_examples'."
    psql -c "CREATE DATABASE ""gist_examples"";"
fi

# Run orator migrations interactively.
MIGRATION_PATH=./ 
orator migrate --path=$MIGRATION_PATH

This example assumes that you have orator, python3, and PostgreSQL installed on your local posix-compliant machine. Please, enable execution permissions on setup_example.bash and run_example.py before proceeding. To run the example, illustrating the error that occurs when defining out-of-schema properties on an orator model, run execute the following from the same directory where you have saved the gist files:

$ chmod u+x setup_example.bash run_example.py
$ ./setup_example.bash
$ ./run_example.py

To verify that everything has been correctly setup, comment out line 10 from example_model.py and then rerun the following command:

$ ./run_example.py

If you do not see any errors, then everything has been setup correctly.

Here is the error that appears;

localhost:orator_gist formwalt$ ./setup_example.bash 
Database 'gist_examples' already exists.

Are you sure you want to proceed with the migration? y

[OK] Migrated 2016_12_18_205220_create_table_examples
localhost:orator_gist formwalt$ ./
__pycache__/        run_example.py      setup_example.bash  
localhost:orator_gist formwalt$ ./run_example.py 
==> Here is my example: 'Hello World!'

localhost:orator_gist formwalt$ ./run_example.py 
==> Here is my example: 'Hello World!'

Traceback (most recent call last):
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/connections/connection.py", line 31, in _run
    result = wrapped(self, query, bindings, *args, **kwargs)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/connections/connection.py", line 199, in select
    cursor.execute(query, bindings)
  File "/Applications/anaconda/lib/python3.5/site-packages/psycopg2/extras.py", line 120, in execute
    return super(DictCursor, self).execute(query, vars)
psycopg2.ProgrammingError: column "_Example__name" of relation "examples" does not exist
LINE 1: INSERT INTO "examples" ("_Example__name", "name") VALUES ('T...
                                ^


During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./run_example.py", line 27, in <module>
    example.save()
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/orm/model.py", line 1526, in save
    saved = self._perform_insert(query, options)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/orm/model.py", line 1597, in _perform_insert
    self._insert_and_set_id(query, attributes)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/orm/model.py", line 1619, in _insert_and_set_id
    id = query.insert_get_id(attributes, key_name)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/orm/builder.py", line 1155, in call
    result = attribute(*args, **kwargs)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/query/builder.py", line 1409, in insert_get_id
    return self._processor.process_insert_get_id(self, sql, values, sequence)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/query/processors/postgres_processor.py", line 27, in process_insert_get_id
    result = query.get_connection().select_from_write_connection(sql, values)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/connections/connection.py", line 190, in select_from_write_connection
    return self.select(query, bindings)
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/connections/connection.py", line 34, in _run
    e, query, bindings, wrapped
  File "/Applications/anaconda/lib/python3.5/site-packages/orator/connections/connection.py", line 317, in _try_again_if_caused_by_lost_connection
    raise QueryException(query, bindings, e)
orator.exceptions.query.QueryException: column "_Example__name" of relation "examples" does not exist
LINE 1: INSERT INTO "examples" ("_Example__name", "name") VALUES ('T...
                                ^
 (SQL: INSERT INTO "examples" ("_Example__name", "name") VALUES (%s, %s) RETURNING "id" (['This world is so confusing from the inside!', 'Hello World!']))
localhost:orator_gist formwalt$