Below is an example of an MQL constraint formula:
OR([BT_CUSTOMERS.BC_CUSTOMERS_CUSTOMERNAME] = "EuroCars";
(([BT_CUSTOMERS.BC_CUSTOMERS_CREDITLIMIT] * 2) / 3 > 1000))
Note the OR function. This is a Boolean function that has two parameters, separated by semicolons. These parameters are Boolean expressions. The first Boolean expression references a business column from the metadata model. All references appear with brackets around them []. This reference refers to the business table, and then to the business column. This Boolean expression does some arithmetic and checks to see if the final value is larger than 1000. In the second expression, business column BT_CUSTOMERS.BC_CUSTOMERS_CUSTOMERNAME is compared to EuroCars. Double quotation marks are used when referring to text. Double quotation marks are required.