DairyBrainUtils 0.3.3

A set of functions that interacts with a database. It contains some basic functionalities along with some other Dairy-Brain-specific functionalities.

AgDH_DairyBrainUtils

• AgDH_DairyBrainUtils
  • About
  • Installation
  • Documentation
  • Development

About

DairyBrainUtils is a PyPI package with some basic functionalities for interacting with a PostgreSQL database.

For now, it is hosted on TestPyPI. If the TestPyPI distribution got cleaned up, please contact the author to re-upload it.

Installation

To install the latest version of the package, use the command in PyPI.

If the above link is broken, try:

pip install DairyBrainUtils

Once installed, we recommend you to import the package with import DairyBrainUtils as dbu.

(Update: This was resolved as we uploaded to the official PyPI) If you see an error message like this:

ERROR: Could not find a version that satisfies the requirement DairyBrainUtils-ruipeterpan==0.3.0 (from versions: 0.0.3, 0.0.4, 0.1.0, 0.1.1, 0.1.2, 0.1.3, 0.2.0, 0.2.1)
ERROR: No matching distribution found for DairyBrainUtils-ruipeterpan==0.3.0

try installing it one more time. TestPyPI is weird.

Documentation

A list of functions that are available for use are:

• get_engine(credentials)
• check_if_database_exists(db_engine)
• create_table_if_doesnt_exist(db_engine, table_name, sql_statement)
• create_table(db_engine, table_name, sql_statement)
• create_schema(db_engine, schema_name)
• create_sequence(db_engine, sequence_name)
• get_next_from_sequence(db_engine, sequence_name)
• populate_table_from_csv(table_name, csv_location, db_engine)
• execute_statement(statement, db_engine)
• drop_table(table_name, db_engine)
• has_table(table_name, db_engine)

get_engine(credentials)

Takes in a dictionary credentials with the keys: [dialect, user, password, host, port, db_name, log], and passes these credentials into sqlalchemy.create_engine() to create a new engine instance.

• dialect: String. A database dialect. Right now this package only supports postgresql.
• user: String. The username of a user in the database.
• password: String. The password that is associated with the user.
• host: String. Host name.
• port: Integer. Port number.
• db_name: String. A database name.
• log: Boolean. If True, the engine will log all statements as well as a repr() of their parameter lists to the engines logger, which defaults to sys.stdout.

check_if_database_exists(db_engine)

Use existing sqlalchemy functionality to check if the database exists. Returns 'True' if database exists, 'False' otherwise

create_table_if_doesnt_exist(db_engine, table_name, sql_statement)

Creates a table with table_name in the database if a table with the given name doesn't exist.

sql_statement is a CREATE TABLE statement that specifies the headers of the table to be created.

create_table(db_engine, table_name, sql_statement)

Creates a table with table_name in the database.

sql_statement is a CREATE TABLE statement that specifies the headers of the table to be created.

create_schema(db_engine, schema_name)

Creates a schema with the given schema_name in the specified database.

create_sequence(db_engine, sequence_name)

Creates a sequence in the database.

get_next_from_sequence(db_engine, sequence_name)

Returns the next integer id in the given sequence (assuming one exists)

populate_table_from_csv(table_name, csv_location, db_engine)

Takes in a csv_location, the file path of a csv file, and populates the table with the given table_name (assuming one exists) in the specified database.

execute_statement(statement, db_engine)

Executes a SQL statement in the specified database.

drop_table(table_name, db_engine)

Drops a table with table_name in the specified database.

has_table(table_name, db_engine)

Returns True if there exists a table with the given table_name in the specified database, returns False otherwise

Development

See this tutorial for guidance on packaging a Python project and uploading it to the PyPI (Python Package Index). This is a sample project with the best format.

To publish a new version of the package, edit ./DairyBrainUtils/__init__.py, change the version number in setup.py, and publish the distribution archives following the tutorial.

More specifically, do:

python3 -m pip install --upgrade setuptools wheel
python3 setup.py sdist bdist_wheel

Now, a dist directory should be created with two files. If the package is to be hosted on a local server, just take the .whl file and use pip to install the package.

For uploading the distribution packages to TestPyPI, do:

python3 -m pip install --upgrade twine
python3 -m twine upload --repository testpypi dist/*

Use __token__ when prompted to enter the username. For the password, use the token value, including the pypi- prefix.