DÉCRIRE LA BASE DE DONNÉESDESCRIBE DATABASE

DESCRIBE DATABASE l’instruction retourne les métadonnées d’une base de données existante.DESCRIBE DATABASE statement returns the metadata of an existing database. Les informations de métadonnées incluent le nom de la base de données, le commentaire de la base de données et l’emplacement de la base de données.The metadata information includes database name, database comment, and database location on the filesystem. Si l' EXTENDED option facultative est spécifiée, elle retourne les informations de métadonnées de base ainsi que les propriétés de la base de données.If the optional EXTENDED option is specified, it returns the basic metadata information along with the database properties. Les DATABASE et SCHEMA sont interchangeables.The DATABASE and SCHEMA are interchangeable.

SyntaxeSyntax

{ DESC | DESCRIBE } DATABASE [ EXTENDED ] db_name

ParamètresParameters

  • db_name: nom d’une base de données existante ou d’un schéma existant dans le système.db_name: The name of an existing database or an existing schema in the system. Si le nom n’existe pas, une exception est levée.If the name does not exist, an exception is thrown.

ExemplesExamples

-- Create employees DATABASE
CREATE DATABASE employees COMMENT 'For software companies';

-- Describe employees DATABASE.
-- Returns Database Name, Description and Root location of the filesystem
-- for the employees DATABASE.
DESCRIBE DATABASE employees;
+-------------------------+-----------------------------+
|database_description_item|   database_description_value|
+-------------------------+-----------------------------+
|            Database Name|                    employees|
|              Description|       For software companies|
|                 Location|file:/you/Temp/employees.db  |
+-------------------------+-----------------------------+

-- Create employees DATABASE
CREATE DATABASE employees COMMENT 'For software companies';

-- Alter employees database to set DBPROPERTIES
ALTER DATABASE employees SET DBPROPERTIES ('Create-by' = 'Kevin', 'Create-date' = '09/01/2019');

-- Describe employees DATABASE with EXTENDED option to return additional database properties
DESCRIBE DATABASE EXTENDED employees;
+-------------------------+---------------------------------------------+
|database_description_item|                   database_description_value|
+-------------------------+---------------------------------------------+
|            Database Name|                                    employees|
|              Description|                       For software companies|
|                 Location|                file:/you/Temp/employees.db  |
|               Properties|((Create-by,kevin), (Create-date,09/01/2019))|
+-------------------------+---------------------------------------------+

-- Create deployment SCHEMA
CREATE SCHEMA deployment COMMENT 'Deployment environment';

-- Describe deployment, the DATABASE and SCHEMA are interchangeable, your meaning are the same.
DESC DATABASE deployment;
+-------------------------+------------------------------+
|database_description_item|database_description_value    |
+-------------------------+------------------------------+
|            Database Name|                    deployment|
|              Description|        Deployment environment|
|                 Location|file:/you/Temp/deployment.db  |
+-------------------------+------------------------------+