COMMENT ON statements let you create comments on database objects, such as schemas, tables, and libraries. Each object can have one comment. Comments are stored in the system table
COMMENTS.
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COMMENT ON statements
COMMENT ON statements let you create comments on database objects, such as schemas, tables, and libraries.
- 1: COMMENT ON AGGREGATE FUNCTION
- 2: COMMENT ON ANALYTIC FUNCTION
- 3: COMMENT ON COLUMN
- 4: COMMENT ON CONSTRAINT
- 5: COMMENT ON FUNCTION
- 6: COMMENT ON LIBRARY
- 7: COMMENT ON NODE
- 8: COMMENT ON PROJECTION
- 9: COMMENT ON SCHEMA
- 10: COMMENT ON SEQUENCE
- 11: COMMENT ON TABLE
- 12: COMMENT ON TRANSFORM FUNCTION
- 13: COMMENT ON VIEW
1 - COMMENT ON AGGREGATE FUNCTION
Adds, revises, or removes a comment on an aggregate function.
Adds, revises, or removes a comment on an aggregate function. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON AGGREGATE FUNCTION [[database.]schema.]function (function-args) IS { 'comment' | NULL };
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.function- The name of the aggregate function with which to associate the comment.
function-args- The function arguments.
comment- Specifies the comment text to add. If a comment already exists for this function, this overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the APPROXIMATE_MEDIAN(x FLOAT) function:
=> COMMENT ON AGGREGATE FUNCTION APPROXIMATE_MEDIAN(x FLOAT) IS 'alias of APPROXIMATE_PERCENTILE with 0.5 as its parameter';
The following example removes a comment from the APPROXIMATE_MEDIAN(x FLOAT) function:
=> COMMENT ON AGGREGATE FUNCTION APPROXIMATE_MEDIAN(x FLOAT) IS NULL;
2 - COMMENT ON ANALYTIC FUNCTION
Adds, revises, or removes a comment on an analytic function.
Adds, revises, or removes a comment on an analytic function. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON ANALYTIC FUNCTION [[database.]schema.]function (function-args) IS { 'comment' | NULL };
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.function- The name of the analytic function with which to associate the comment.
function-args- The function arguments.
comment- Specifies the comment text to add. If a comment already exists for this function, this overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the user-defined an_rank() function:
=> COMMENT ON ANALYTIC FUNCTION an_rank() IS 'built from the AnalyticFunctions library';
The following example removes a comment from the user-defined an_rank() function:
=> COMMENT ON ANALYTIC FUNCTION an_rank() IS NULL;
3 - COMMENT ON COLUMN
Adds, revises, or removes a comment on a column in a table or projection.
Adds, revises, or removes a comment on a column in a table or projection. Each object can have one comment. Comments are stored in the COMMENTS system table.
Syntax
COMMENT ON COLUMN [[database.]schema.]object.column IS {'comment' | NULL}
Arguments
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.object- Name of the table or projection containing the column.
column- Name of the column to which the comment applies.
comment| NULL- Comment text to add, or NULL to remove an existing comment. The new value replaces any existing comment for this column.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment for a table column:
=> COMMENT ON COLUMN store.store_sales_fact.transaction_time IS 'GMT';
You can also add comments to columns in projections:
=> COMMENT ON COLUMN customer_dimension_vmart_node01.customer_name IS 'Last name only';
To remove a comment, specify NULL:
=> COMMENT ON COLUMN store.store_sales_fact.transaction_time IS NULL;
4 - COMMENT ON CONSTRAINT
Adds, revises, or removes a comment on a constraint.
Adds, revises, or removes a comment on a constraint. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON CONSTRAINT constraint ON [[database.]schema.]table IS ... {'comment' | NULL };
Parameters
constraint- The name of the constraint associated with the comment.
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.table- The name of the table constraint with which to associate a comment.
comment- Specifies the comment text to add. If a comment already exists for this constraint, this comment overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the constraint_x constraint on the promotion_dimension table:
=> COMMENT ON CONSTRAINT constraint_x ON promotion_dimension IS 'Primary key';
The following example removes a comment from the constraint_x constraint on the promotion_dimension table:
=> COMMENT ON CONSTRAINT constraint_x ON promotion_dimension IS NULL;
5 - COMMENT ON FUNCTION
Adds, revises, or removes a comment on a function.
Adds, revises, or removes a comment on a function. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON FUNCTION [[database.]schema.]function (function-args) IS { 'comment' | NULL };
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.function- The name of the function with which to associate the comment.
function-args- The function arguments.
comment- Specifies the comment text to add. If a comment already exists for this function, this overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the macros.zerowhennull (x INT) function:
=> COMMENT ON FUNCTION macros.zerowhennull(x INT) IS 'Returns a 0 if not NULL';
The following example removes a comment from the macros.zerowhennull (x INT) function:
=> COMMENT ON FUNCTION macros.zerowhennull(x INT) IS NULL;
6 - COMMENT ON LIBRARY
Adds, revises, or removes a comment on a library.
Adds, revises, or removes a comment on a library . Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON LIBRARY [[database.]schema.]library IS {'comment' | NULL}
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.library- The name of the library associated with the comment.
comment- Specifies the comment text to add. If a comment already exists for this library, this comment overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the library MyFunctions:
=> COMMENT ON LIBRARY MyFunctions IS 'In development';
The following example removes a comment from the library MyFunctions:
=> COMMENT ON LIBRARY MyFunctions IS NULL;
See also
7 - COMMENT ON NODE
Adds, revises, or removes a comment on a node.
Adds, revises, or removes a comment on a node. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Dropping an object drops all comments associated with the object.
Syntax
COMMENT ON NODE node-name IS { 'comment' | NULL }
Parameters
node-name- The name of the node associated with the comment.
comment- Specifies the comment text to add. If a comment already exists for this node, this comment overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment for the initiator node:
=> COMMENT ON NODE initiator IS 'Initiator node';
The following example removes a comment from the initiator node:
=> COMMENT ON NODE initiator IS NULL;
See also
COMMENTS8 - COMMENT ON PROJECTION
Adds, revises, or removes a comment on a projection.
Adds, revises, or removes a comment on a projection. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Dropping an object drops all comments associated with the object.
Syntax
COMMENT ON PROJECTION [[database.]schema.]projection IS { 'comment' | NULL }
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.projection- The name of the projection associated with the comment.
comment- Specifies the text of the comment to add. If a comment already exists for this projection, the comment you enter here overwrites the previous comment.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the customer_dimension_vmart_node01 projection:
=> COMMENT ON PROJECTION customer_dimension_vmart_node01 IS 'Test data';
The following example removes a comment from the customer_dimension_vmart_node01 projection:
=> COMMENT ON PROJECTION customer_dimension_vmart_node01 IS NULL;
See also
COMMENTS9 - COMMENT ON SCHEMA
Adds, revises, or removes a comment on a schema.
Adds, revises, or removes a comment on a schema. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON SCHEMA schema-name IS {'comment' | NULL}
Parameters
schema-name- The schema associated with the comment.
comment- Text of the comment to add. If a comment already exists for this schema, the comment you enter here overwrites the previous comment.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the public schema:
=> COMMENT ON SCHEMA public IS 'All users can access this schema';
The following example removes a comment from the public schema.
=> COMMENT ON SCHEMA public IS NULL;
10 - COMMENT ON SEQUENCE
Adds, revises, or removes a comment on a sequence.
Adds, revises, or removes a comment on a sequence. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON SEQUENCE [[database.]schema.]sequence IS { 'comment' | NULL }
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.sequence- The name of the sequence associated with the comment.
comment- Specifies the text of the comment to add. If a comment already exists for this sequence, this comment overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the sequence called prom_seq.
=> COMMENT ON SEQUENCE prom_seq IS 'Promotion codes';
The following example removes a comment from the prom_seq sequence.
=> COMMENT ON SEQUENCE prom_seq IS NULL;
11 - COMMENT ON TABLE
Adds, revises, or removes a comment on a table.
Adds, revises, or removes a comment on a table. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON TABLE [[database.]schema.]table IS { 'comment' | NULL }
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.table- The name of the table with which to associate the comment.
comment- Specifies the text of the comment to add. Enclose the text of the comment within single-quotes. If a comment already exists for this table, the comment you enter here overwrites the previous comment.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes a previously added comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the promotion_dimension table:
=> COMMENT ON TABLE promotion_dimension IS '2011 Promotions';
The following example removes a comment from the promotion_dimension table:
=> COMMENT ON TABLE promotion_dimension IS NULL;
12 - COMMENT ON TRANSFORM FUNCTION
Adds, revises, or removes a comment on a user-defined transform function.
Adds, revises, or removes a comment on a user-defined transform function. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON TRANSFORM FUNCTION [[database.]schema.]tfunction
...( [ tfunction-arg-name tfunction-arg-type ][,...] ) IS {'comment' | NULL}
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.tfunction- The name of the transform function with which to associate the comment.
-
tfunction-arg-name tfunction-arg-type - The names and data types of one or more transform function arguments. If you supply argument names and types, each type must match the type specified in the library used to create the original transform function.
comment- Specifies the comment text to add. If a comment already exists for this transform function, this comment overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the macros.zerowhennull (x INT) UTF function:
=> COMMENT ON TRANSFORM FUNCTION macros.zerowhennull(x INT) IS 'Returns a 0 if not NULL';
The following example removes a comment from the acros.zerowhennull (x INT) function by using the NULL option:
=> COMMENT ON TRANSFORM FUNCTION macros.zerowhennull(x INT) IS NULL;
13 - COMMENT ON VIEW
Adds, revises, or removes a comment on a view.
Adds, revises, or removes a comment on a view. Each object can have one comment. Comments are stored in the system table
COMMENTS.
Syntax
COMMENT ON VIEW [[database.]schema.]view IS { 'comment' | NULL }
Parameters
[database.]schemaDatabase and schema. The default schema is
public. If you specify a database, it must be the current database.view- The name of the view with which to associate the comment.
comment- Specifies the text of the comment to add. If a comment already exists for this view, this comment overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message.
NULL- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment from the curr_month_ship view:
=> COMMENT ON VIEW curr_month_ship IS 'Shipping data for the current month';
The following example removes a comment from the curr_month_ship view:
=> COMMENT ON VIEW curr_month_ship IS NULL;