boolean

Definition

A boolean is used whenever you have a column or SQL expression that returns True or False (i.e., yes or no).

Usage

Assume our order table contains a column indicating whether an order was returned ('yes') or not ('no'). To configure this column as a boolean attribute, we use the following VKL definition:

import: [
    db.postgres.movie_db.public.ORDERS
]

kb {
    class Order {

        ...

        boolean Returned {
            name.en: "Returned"

            sql: "${ORDERS.returned} = 'yes'"
        }
    }
}

For boolean, the sql property can be any kind of SQL boolean expression.

The name of a boolean attribute refers to the case where the SQL expression evaluates to True. That is, asking about "Returned Orders" will show the orders whose Returned boolean is True.

Naming the Negated Case

Veezoo allows optionally providing a name and synonyms for the case when the boolean is False.

For instance, assume we are using Veezoo on a flight dataset indicating for each flight the origin and destination country. We would like to model whether a flight is domestic using a boolean. If a flight is not domestic, it is international. We can instruct Veezoo to treat "international" as a synonym for "not domestic" using the negated property as follows:

import: [
    db.postgres.flights_db.public.FLIGHTS
]

kb {

    class Flight {

        ...
        boolean is_Domestic {
            name.en: "Domestic"

            sql: "${FLIGHTS.from_country} = ${FLIGHTS.to_country}"

            negated: {
                name.en: "International"
            }
        }
    }
}

We can define additional synonyms for "international" by adding synonym properties inside the negated object.