Using the COMMENT command v17

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In addition to allowing comments on objects supported by the PostgreSQL COMMENT command, EDB Postgres Advanced Server supports comments on other object types. The complete supported syntax is:

COMMENT ON
{
  AGGREGATE <aggregate_name> ( <aggregate_signature> ) |
  CAST (<source_type> AS <target_type>) |
  COLLATION <object_name> |
  COLUMN <relation_name>.<column_name> |
  CONSTRAINT <constraint_name> ON <table_name> |
  CONSTRAINT <constraint_name> ON DOMAIN <domain_name> |
  CONVERSION <object_name> |
  DATABASE <object_name> |
  DOMAIN <object_name> |
  EXTENSION <object_name> |
  EVENT TRIGGER <object_name> |
  FOREIGN DATA WRAPPER <object_name> |
  FOREIGN TABLE <object_name> |
  FUNCTION <func_name> ([[<argmode>] [<argname>] <argtype> [,...]])|
  INDEX <object_name> |
  LARGE OBJECT <large_object_oid> |
  MATERIALIZED VIEW <object_name> |
  OPERATOR <operator_name> (left_type, right_type) |
  OPERATOR CLASS <object_name> USING <index_method> |
  OPERATOR FAMILY <object_name> USING <index_method> |
  PACKAGE <object_name>
  POLICY <policy_name> ON <table_name> |
  [ PROCEDURAL ] LANGUAGE <object_name> |
  PROCEDURE <proc_name> [([[<argmode>] [<argname>] <argtype> [, ...]])]
  PUBLIC SYNONYM <object_name>
  ROLE <object_name> |
  RULE <rule_name> ON <table_name> |
  SCHEMA <object_name> |
  SEQUENCE <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> |
  TRANSFORM FOR <type_name> LANGUAGE <lang_name> |
  TRIGGER <trigger_name> ON <table_name> |
  TYPE <object_name> |
  VIEW <object_name>
} IS <'text'>

Where aggregate_signature is:

* |
[ <argmode> ] [ <argname> ] <argtype> [ , ... ] |
[ [ <argmode> ] [ <argname> ] <argtype> [ , ... ] ]
ORDER BY [ <argmode> ] [ <argname> ] <argtype> [ , ... ]

Parameters

object_name

The name of the object on which you're commenting.

AGGREGATE aggregate_name (aggregate_signature)

Include the AGGREGATE clause to create a comment about an aggregate. aggregate_name specifies the name of an aggregate. aggregate_signature specifies the associated signature in one of the following forms:

* |
[ <argmode> ] [ <argname> ] <argtype> [ , ... ] |
[ [ <argmode> ] [ <argname> ] <argtype> [ , ... ] ]
ORDER BY [ <argmode> ] [ <argname> ] <argtype> [ , ... ]

Where argmode is the mode of a function, procedure, or aggregate argument. argmode can be IN, OUT, INOUT, or VARIADIC. The default is IN.

argname is the name of an aggregate argument.

argtype is the data type of an aggregate argument.

CAST (source_type AS target_type)

Include the CAST clause to create a comment about a cast. When creating a comment about a cast, source_type specifies the source data type of the cast, and target_type specifies the target data type of the cast.

COLUMN relation_name.column_name

Include the COLUMN clause to create a comment about a column. column_name specifies the name of the column to which the comment applies. relation_name is the table, view, composite type, or foreign table in which a column resides.

CONSTRAINT constraint_name ON table_name

CONSTRAINT constraint_name ON DOMAIN domain_name

Include the CONSTRAINT clause to add a comment about a constraint. When you're creating a comment about a constraint, constraint_name specifies the name of the constraint. table_name or domain_name specifies the name of the table or domain on which the constraint is defined.

FUNCTION func_name ([[argmode] [argname] argtype [, ...]])

Include the FUNCTION clause to add a comment about a function. func_name specifies the name of the function. argmode specifies the mode of the function. argmode can be IN, OUT, INOUT, or VARIADIC. The default is IN.

argname specifies the name of a function, procedure, or aggregate argument. argtype specifies the data type of a function, procedure, or aggregate argument.

large_object_oid

large_object_oid is the system-assigned OID of the large object about which you're commenting.

OPERATOR operator_name (left_type, right_type)

Include the OPERATOR clause to add a comment about an operator. operator_name specifies the optionally schema-qualified name of an operator on which you're commenting. left_type and right_type are the optionally schema-qualified data types of the operator's arguments.

OPERATOR CLASS object_name USING index_method

Include the OPERATOR CLASS clause to add a comment about an operator class. object_name specifies the optionally schema-qualified name of an operator on which you're commenting. index_method specifies the associated index method of the operator class.

OPERATOR FAMILY object_name USING index_method

Include the OPERATOR FAMILY clause to add a comment about an operator family. object_name specifies the optionally schema-qualified name of an operator family on which you're commenting. index_method specifies the associated index method of the operator family.

POLICY policy_name ON table_name

Include the POLICY clause to add a comment about a policy. policy_name specifies the name of the policy. table_name specifies the table that the policy is associated with.

PROCEDURE proc_name [([[argmode] [argname] argtype [, ...]])]

Include the PROCEDURE clause to add a comment about a procedure. proc_name specifies the name of the procedure. argmode specifies the mode of the procedure. argmode can be IN, OUT, INOUT, or VARIADIC. The default is IN.

argname specifies the name of a function, procedure, or aggregate argument. argtype specifies the data type of a function, procedure, or aggregate argument.

RULE rule_name ON table_name

Include the RULE clause to specify a comment on a rule. rule_name specifies the name of the rule. table_name specifies the name of the table on which the rule is defined.

TRANSFORM FOR type_name LANGUAGE lang_name

Include the TRANSFORM FOR clause to specify a comment on a TRANSFORM.

type_name specifies the name of the data type of the transform. lang_name specifies the name of the language of the transform.

TRIGGER trigger_name ON table_name

Include the TRIGGER clause to specify a comment on a trigger. trigger_name specifies the name of the trigger. table_name specifies the name of the table on which the trigger is defined.

text

The comment, written as a string literal, or NULL to drop the comment.

Note

Names of tables, aggregates, collations, conversions, domains, foreign tables, functions, indexes, operators, operator classes, operator families, packages, procedures, sequences, text search objects, types, and views can be schema qualified.

Example

This example adds a comment to a table named new_emp:

COMMENT ON TABLE new_emp IS 'This table contains information about new
employees.';

For more information about using the COMMENT command, see the PostgreSQL core documentation.

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