database.md

Database operations

Introduction

The database related contents are split between two packages:

• dialect_map_core: defining a CLI (dm-admin) to perform setup, teardown and loading operations.
• dialect_map_data: containing testing files loadable thanks to the file-to-model mappings.

For now, the only supported SQL database is PostgreSQL, although other ones can be easily added thanks to the use of (SQLAlchemy).

Database

To start a local PostgreSQL database, install the PostgreSQL binaries through their website or by one of your OS package managers

• For Ubuntu: apt install postgresql.
• For Mac OS: brew install postgresql.

Then run:

$ sudo mkdir -p /usr/local/var/postgres
$ sudo chown $(whoami) /usr/local/var/postgres
$ initdb -D /usr/local/var/postgres
$ postgres -D /usr/local/var/postgres

Finally, create the admin user and database partition by running:

$ psql --dbname=postgres
postgres=# CREATE USER dm;
postgres=# ALTER USER dm WITH PASSWORD 'dmpwd';
postgres=# CREATE DATABASE dialect_map WITH OWNER dm;

CLI Commands

List of available operations to perform using the Dialect Map CLI:

Setup

Creates all the necessary tables, indexes, relationships and constraints.

$ dm-admin setup-db

PARAMETER	ENV. VARIABLE	REQUIRED	DEFAULT	DESCRIPTION
--url	DIALECT_MAP_DB_URL	No	...	Database connection URL

Teardown

Deletes all the tables, indexes, relationships and constraints.

$ dm-admin teardown-db

PARAMETER	ENV. VARIABLE	REQUIRED	DEFAULT	DESCRIPTION
--url	DIALECT_MAP_DB_URL	No	...	Database connection URL
--force	-	No	False	Whether to delete non-empty tables

Load

Loads testing data into the desired database instance

$ dm-admin load-db

PARAMETER	ENV. VARIABLE	REQUIRED	DEFAULT	DESCRIPTION
--url	DIALECT_MAP_DB_URL	No	...	Database connection URL