Compute
Elastic Cloud Server
Huawei Cloud Flexus
Bare Metal Server
Auto Scaling
Image Management Service
Dedicated Host
FunctionGraph
Cloud Phone Host
Huawei Cloud EulerOS
Networking
Virtual Private Cloud
Elastic IP
Elastic Load Balance
NAT Gateway
Direct Connect
Virtual Private Network
VPC Endpoint
Cloud Connect
Enterprise Router
Enterprise Switch
Global Accelerator
Management & Governance
Cloud Eye
Identity and Access Management
Cloud Trace Service
Resource Formation Service
Tag Management Service
Log Tank Service
Config
OneAccess
Resource Access Manager
Simple Message Notification
Application Performance Management
Application Operations Management
Organizations
Optimization Advisor
IAM Identity Center
Cloud Operations Center
Resource Governance Center
Migration
Server Migration Service
Object Storage Migration Service
Cloud Data Migration
Migration Center
Cloud Ecosystem
KooGallery
Partner Center
User Support
My Account
Billing Center
Cost Center
Resource Center
Enterprise Management
Service Tickets
HUAWEI CLOUD (International) FAQs
ICP Filing
Support Plans
My Credentials
Customer Operation Capabilities
Partner Support Plans
Professional Services
Analytics
MapReduce Service
Data Lake Insight
CloudTable Service
Cloud Search Service
Data Lake Visualization
Data Ingestion Service
GaussDB(DWS)
DataArts Studio
Data Lake Factory
DataArts Lake Formation
IoT
IoT Device Access
Others
Product Pricing Details
System Permissions
Console Quick Start
Common FAQs
Instructions for Associating with a HUAWEI CLOUD Partner
Message Center
Security & Compliance
Security Technologies and Applications
Web Application Firewall
Host Security Service
Cloud Firewall
SecMaster
Anti-DDoS Service
Data Encryption Workshop
Database Security Service
Cloud Bastion Host
Data Security Center
Cloud Certificate Manager
Edge Security
Managed Threat Detection
Blockchain
Blockchain Service
Web3 Node Engine Service
Media Services
Media Processing Center
Video On Demand
Live
SparkRTC
MetaStudio
Storage
Object Storage Service
Elastic Volume Service
Cloud Backup and Recovery
Storage Disaster Recovery Service
Scalable File Service Turbo
Scalable File Service
Volume Backup Service
Cloud Server Backup Service
Data Express Service
Dedicated Distributed Storage Service
Containers
Cloud Container Engine
SoftWare Repository for Container
Application Service Mesh
Ubiquitous Cloud Native Service
Cloud Container Instance
Databases
Relational Database Service
Document Database Service
Data Admin Service
Data Replication Service
GeminiDB
GaussDB
Distributed Database Middleware
Database and Application Migration UGO
TaurusDB
Middleware
Distributed Cache Service
API Gateway
Distributed Message Service for Kafka
Distributed Message Service for RabbitMQ
Distributed Message Service for RocketMQ
Cloud Service Engine
Multi-Site High Availability Service
EventGrid
Dedicated Cloud
Dedicated Computing Cluster
Business Applications
Workspace
ROMA Connect
Message & SMS
Domain Name Service
Edge Data Center Management
Meeting
AI
Face Recognition Service
Graph Engine Service
Content Moderation
Image Recognition
Optical Character Recognition
ModelArts
ImageSearch
Conversational Bot Service
Speech Interaction Service
Huawei HiLens
Video Intelligent Analysis Service
Developer Tools
SDK Developer Guide
API Request Signing Guide
Terraform
Koo Command Line Interface
Content Delivery & Edge Computing
Content Delivery Network
Intelligent EdgeFabric
CloudPond
Intelligent EdgeCloud
Solutions
SAP Cloud
High Performance Computing
Developer Services
ServiceStage
CodeArts
CodeArts PerfTest
CodeArts Req
CodeArts Pipeline
CodeArts Build
CodeArts Deploy
CodeArts Artifact
CodeArts TestPlan
CodeArts Check
CodeArts Repo
Cloud Application Engine
MacroVerse aPaaS
KooMessage
KooPhone
KooDrive

COMMENT

Updated on 2023-10-23 GMT+08:00

Function

COMMENT defines or changes the comment of an object.

Precautions

  • Each object stores only one comment. Therefore, you need to modify a comment and issue a new COMMENT command to the same object. To delete the comment, write NULL at the position of the text string. When an object is deleted, the comment is automatically deleted.
  • Currently, there is no security protection for viewing comments. Any user connected to a database can view all the comments for objects in the database. For shared objects such as databases, roles, and tablespaces, comments are stored globally so any user connected to any database in the cluster can see all the comments for shared objects. Therefore, do not put security-critical information in comments.
  • To comment objects, you must be an object owner or user granted the COMMENT permission. The system administrator has this permission by default.
  • Roles do not have owners, so the rule for COMMENT ON ROLE is that you must be an administrator to comment on an administrator role, or have the CREATEROLE permission to comment on non-administrator roles. A system administrator can comment on all objects.

Syntax

COMMENT ON
{
  AGGREGATE agg_name (agg_type [, ...] ) |
  CAST (source_type AS target_type) |
  COLLATION object_name |
  COLUMN { table_name.column_name | view_name.column_name } |
  CONSTRAINT constraint_name ON table_name |
  CONVERSION object_name |
  DATABASE object_name |
  DOMAIN object_name |
  EXTENSION object_name |
  FOREIGN DATA WRAPPER object_name |
  FOREIGN TABLE object_name |
  FUNCTION function_name ( [ {[ argname ] [ argmode ] argtype} [, ...] ] ) |
  INDEX object_name |
  LARGE OBJECT large_object_oid |
  OPERATOR operator_name (left_type, right_type) |
  OPERATOR CLASS object_name USING index_method |
  OPERATOR FAMILY object_name USING index_method |
  [ PROCEDURAL ] LANGUAGE object_name |
  ROLE object_name |
  SCHEMA object_name |
  SERVER object_name |
  TABLE object_name |
  TABLESPACE object_name |
  TEXT SEARCH CONFIGURATION object_name |
  TEXT SEARCH DICTIONARY object_name |
  TEXT SEARCH PARSER object_name |
  TEXT SEARCH TEMPLATE object_name |
  TYPE object_name |
  VIEW object_name |
  TRIGGER trigger_name ON table_name
}
   IS 'text';

Parameter Description

  • agg_name

    Specifies the new name of an aggregate function.

  • agg_type

    Specifies the data type of the aggregate function parameters.

  • source_type

    Specifies the source data type of the cast.

  • target_type

    Specifies the target data type of the cast.

  • object_name

    Specifies the name of an object.

  • table_name.column_name

    view_name.column_name

    Specifies the column whose comment is defined or modified. You can add the table name or view name as the prefix.

  • constraint_name

    Specifies the table constraint whose comment is defined or modified.

  • table_name

    Specifies the name of a table.

  • function_name

    Specifies the function whose comment is defined or modified.

  • argname,argmode,argtype

    Specifies the name, schema, and type of the function parameters.

  • large_object_oid

    Specifies the OID of the large object whose comment is defined or modified.

  • operator_name

    Specifies the name of the operator.

  • left_type,right_type

    Specifies the data type of the operator parameters (optionally schema-qualified). If the prefix or suffix operator does not exist, the NONE option can be added.

  • trigger_name

    Specifies the trigger name.

  • text

    Specifies the comment content.

Examples

openGauss=# CREATE TABLE tpcds.customer_demographics_t2
(
    CD_DEMO_SK                INTEGER               NOT NULL,
    CD_GENDER                 CHAR(1)                       ,
    CD_MARITAL_STATUS         CHAR(1)                       ,
    CD_EDUCATION_STATUS       CHAR(20)                      ,
    CD_PURCHASE_ESTIMATE      INTEGER                       ,
    CD_CREDIT_RATING          CHAR(10)                      ,
    CD_DEP_COUNT              INTEGER                       ,
    CD_DEP_EMPLOYED_COUNT     INTEGER                       ,
    CD_DEP_COLLEGE_COUNT      INTEGER
)
WITH (ORIENTATION = COLUMN,COMPRESSION=MIDDLE)
;

-- Comment out the tpcds.customer_demographics_t2.cd_demo_sk column.
openGauss=# COMMENT ON COLUMN tpcds.customer_demographics_t2.cd_demo_sk IS 'Primary key of customer demographics table.';

-- Create a view consisting of rows with c_customer_sk less than 150.
openGauss=# CREATE VIEW tpcds.customer_details_view_v2 AS
    SELECT *
    FROM tpcds.customer
    WHERE c_customer_sk < 150;

-- Comment out the tpcds.customer_details_view_v2 view.
openGauss=# COMMENT ON VIEW tpcds.customer_details_view_v2 IS 'View of customer detail';

-- Delete the view.
openGauss=# DROP VIEW tpcds.customer_details_view_v2;

-- Delete the tpcds.customer_demographics_t2 table.
openGauss=# DROP TABLE tpcds.customer_demographics_t2;

We use cookies to improve our site and your experience. By continuing to browse our site you accept our cookie policy. Find out more

Feedback

Feedback

Feedback

0/500

Selected Content

Submit selected content with the feedback