Mysql Numeric / Decimal fields

class product {
/**
*Column(type="decimal", scale="2")
*
*/
private $discount;
}

generate SQL

create table product {
discount DECIMAL(10,2) NOT NULL
}

if you have a field in a database type DECIMAL doctrine tries to
generate for him diff

doctrine orm:schema-tool
>
ALTER TABLE product CHANGE discrount discrount NUMERIC (10, 2) NOT NULL

but mysql ignore the alter, as a result of these diff stretch from
migration to migration