1. Overview#

1.1. Command Line Interface#

Command Line Interface

  • Showing CLI commands.

1.2. Rich Database Metadata#

Note

More information about the metadata can be found under design/metadata

Rich Metadata
  • Showing the metadata tables.

    • dvc.database_revision_history table which shows the revision SQL files applied.

    • dvc.database_version_history table which shows the database version which results from the revision SQL files applied.

1.3. Upgrade or Downgrade#

Rich Metadata
  • Showing upgrade and downgrade command.

    • Started from database version 1 (Shown via dvc db current)

    • Showed the Revision SQL files under the default folder sample_revision_sql_files.

    • Applied database upgrade via dvc db upgrade.

    • Showed the database version became 2.

    • Applied database downgrade via dvc db downgrade.

    • Showed the database version was back to 1.

1.4. Flexible Configuration Format#

Configuration is read either from i. Configuration File (config.yaml) or ii. Environment Variable

1.4.1. Configuration File#

Note

The configuration file template can be generated via dvc cfg init

Config Via Configuration File
  • Showing dvc tool reads configuration from a configuration file.

    • Ran a postgres DB via docker docker run -e POSTGRES_USER=test -e POSTGRES_PASSWORD=test -e POSTGRES_DB=test -p 5433:5432 postgres:latest

    • Copied a config.yaml file with configurations which match the spun up postgres DB.

    • Pinged the DB with dvc db ping. Success!

  • The config.yaml file looks as follows:

credentials:
  dbflavour: postgres
  dbname: 'test'
  host: 'localhost'
  password: 'test'
  port: 5433
  user: 'test'
database_revision_sql_files_folder: sample_revision_sql_files
logging_level: DEBUG

1.4.2. Environment Variable#

Note

The names of the environment variables can be found in the docker compose file

Config Via Env Var
  • Showing dvc tool reads configuration from environment variables

    • Ran a postgres DB via docker docker run -e POSTGRES_USER=test -e POSTGRES_PASSWORD=test -e POSTGRES_DB=test -p 5433:5432 postgres:latest

    • Loaded the env variables to the shell.

    • Pinged the DB with dvc db ping. Success!

  • The environment variables look as follows:

 >>> printnev| grep DVC
 DVC__DATABASE_REVISION_SQL_FILES_FOLDER=sample_revision_sql_files
 DVC__USER=test
 DVC__PASSWORD=test
 DVC__HOST=postgres_db
 DVC__PORT=5432
 DVC__DBNAME=test
 DVC__DBFLAVOUR=postgres
 DVC__LOGGING_LEVEL: DEBUG