Parameters can be used in DML statements in place of values. Parameters must always be preceded by a colon (:). For example,

SELECT LAST_NAME, FIRST_NAME

FROM "CUSTOMER.DB" 

WHERE LAST_NAME > :parm1 AND FIRST_NAME < :parm2 

Assigning an SQL statement with parameters in a Query or StoredProc object automatically creates the corresponding elements in the object’s params array. You then store values to substitute in that array.