You can define the index attributes for a specific column by using the ADD INDEX clause.
ALTER [ TABLE | CLASS ] table_name ADD { KEY | INDEX } [index_name] (<index_col_name>)
<index_col_name> ::=
column_name [(length)] [ ASC | DESC ]
ALTER TABLE a_tbl ADD INDEX (age ASC), ADD INDEX(phone DESC);
;schema a_tbl
=== <Help: Schema of a Class> ===
<Class Name>
a_tbl
<Attributes>
name CHARACTER VARYING(1073741823) DEFAULT ''
phone CHARACTER VARYING(13) DEFAULT '111-1111'
age INTEGER
id INTEGER AUTO_INCREMENT NOT NULL
<Constraints>
UNIQUE u_a_tbl_id ON a_tbl (id)
INDEX i_a_tbl_age ON a_tbl (age)
INDEX i_a_tbl_phone_d ON a_tbl (phone DESC)
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