ALTER FIELD statement

The ALTER FIELD statement is used to change or entirely drop clauses of a defined field on a table.

Statement syntax

SurrealQL Syntax
ALTER FIELD [ IF EXISTS ] ON [ TABLE ] @table 
[ 
    DROP TYPE |
    DROP FLEXIBLE |
    DROP READONLY |
    DROP VALUE |
    DROP ASSERT |
    DROP DEFAULT |
    DROP COMMENT |
    DROP REFERENCE |
    FLEXIBLE |
    READONLY |
    REFERENCE |
    TYPE @type |
    VALUE @value |
    ASSERT @expression |
    DEFAULT [ ALWAYS ] @expression |
    [ PERMISSIONS [ NONE | FULL
		| FOR select @expression
		| FOR create @expression
		| FOR update @expression
		| FOR delete @expression
	] ]
    COMMENT @string |
]

Examples

As ALTER FIELD contains the same clauses available in a DEFINE FIELD statement, be sure to see that page for more examples.

Here is one example in which the name field is defined for a record user:

DEFINE FIELD name ON user TYPE string;

Later on, a database-wide parameter is defined to disallow certain user names. This can be followed up with an ALTER FIELD statement to add the ASSERT clause to it.

DEFINE PARAM $DISALLOWED_NAMES VALUE ["Lord British", "Lord Blackthorn"];
ALTER FIELD name ON user ASSERT $value NOT IN $DISALLOWED_NAMES;
CREATE user SET name = "Lord British";

Output
"Found 'Lord British' for field `name`, with record `user:yn4yttkg5w683q2937bq`, but field must conform to: $value NOTINSIDE $DISALLOWED_NAMES""

See also

• DEFINE FIELD