cozo

View Source Cozo Cheatsheet

Environment Variables

All engines except mem one will create a stored database on filesystem. In case of sqlite a single file will be created, and a directory will be generated with rocksdb.

The default path to store the db can be set modified by configuring db_path environment variable. The directory used must exist, cozo will not create it by default.

application:set_env(cozo, db_path, "/var/tmp").
{ok
, {_
  , #cozo{
	db_path = "/var/tmp/cozodb_JGsr7QVAREITm25Xq5dAw1lOQovHjvL9"
	}
  }
} = cozo:open().

Stored databases are prefixed with cozodb_ by default, but this value can be modified by modifying db_filename_prefix environment variable.

application:set_env(cozo, db_filename_prefix, "cozodb_custom_prefix_").
{ok
, {_
  , #cozo{
	db_path = "/tmp/cozodb_custom_prefixf5anxr5GZ9CJRhVPR2lLMfSviW4CGUip"
	}
  }
} = cozo:open().

mem is the default engine used, this value can be changed by modifying engine environment variable.

application:set_env(cozo, engine, sqlite).

thoas is the default JSON parser used to encode and decode JSON objects. This value can be changed by modiying json_parser environment variable.

application:set_env(cozo, json_parser, thoas).
thoas = cozo:json_encoder().
thoas = cozo:json_decoder().

Databases can use custom options passed as JSON (or map() in this interface). By default, no options (#{}) are passed. This can be modified by changing sqlite_options and rocksdb_options environment variables.

application:set_env(cozo, sqlite_options, #{ custom_option => <<>> }).
application:set_env(cozo, rocksdb_options, #{ custom_option => <<>> }).

The default path to load cozo_nif.so file is set to the priv directory linked from this project. This value can be changed by modifying lib_path environment variable.

application:set_env(cozo, lib_path, "/usr/lib").

Maintenance Commands

A list of functions have been created to help developers to deal with maintenance commands:

  • list_relations/1
  • remove_relation/2
  • remove_relations/2
  • create_relation/3
  • replace_relation/3
  • put_row/3
  • update_row/3
  • remove_row/3
  • ensure_row/3
  • ensure_not_row/3
  • list_columns/2
  • list_indices/2
  • explain/2
  • describe/3
  • get_triggers/2
  • set_access_level/3
  • set_access_levels/3
  • get_running_queries/1
  • kill/2
  • compact/1

Examples

Test suites in test contain the full tutorial from cozodb official documentation.