---
name: "comment"
section: "7l"
platform: "linux"
package: "postgresql"
version: "7.2.1-2woody8"
release: "Debian 3.0 (Woody)"
platforms: ["linux"]
url: "https://new.carta.tech/comment/7l"
---

# comment(7l)

define or change the comment of an object

## NAME

COMMENT - define or change the comment of an object

## SYNOPSIS

```
COMMENT ON
[
  [ DATABASE | INDEX | RULE | SEQUENCE | TABLE | TYPE | VIEW ] object_name |
  COLUMN table_name.column_name |
  AGGREGATE agg_name (agg_type) |
  FUNCTION func_name (arg1, arg2, ...) |
  OPERATOR op (leftoperand_type rightoperand_type) |
  TRIGGER trigger_name ON table_name
] IS 'text'

```

### INPUTS

- *object\_name, table\_name,*

  The name of the object to be be commented.

- *text*

  The comment to add.

### OUTPUTS

- **COMMENT**

  Message returned if the table is successfully commented.

## DESCRIPTION

**COMMENT** stores a comment about a database object. Comments can be  easily retrieved with **psql**'s **\\dd**, **\\d+**, or **\\l+** commands. Other user interfaces to retrieve comments can be built atop the same built-in functions that **psql** uses, namely **obj\_description()** and **col\_description()**.

To modify a comment, issue a new **COMMENT** command for the same object. Only one comment string is stored for each object. To remove a comment, write NULL in place of the text string. Comments are automatically dropped when the object is dropped.

It should be noted that there is presently no security mechanism for comments: any user connected to a database can see all the comments for objects in that database (although only superusers can change comments for objects that they don't own). Therefore, don't put security-critical information in comments.

## USAGE

Comment the table mytable:

```
COMMENT ON mytable IS 'This is my table.';

```

Some more examples:

```
COMMENT ON DATABASE my_database IS 'Development Database';
COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee id';
COMMENT ON RULE my_rule IS 'Logs UPDATES of employee records';
COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
COMMENT ON TABLE my_table IS 'Employee Information';
COMMENT ON TYPE my_type IS 'Complex Number support';
COMMENT ON VIEW my_view IS 'View of departmental costs';
COMMENT ON COLUMN my_table.my_field IS 'Employee ID number';
COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two text';
COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for R.I.';

```

## COMPATIBILITY

### SQL92

There is no **COMMENT** in SQL92.