A forex agency needs a simple table to keep track of the currency exchanges they perform.
Create a table called exchange
with the following columns:
id
- an integer which is the primary key,
currency_from
- exactly three characters,
currency_to
- exactly three characters,
quantity
- a decimal field of 10 digits, 2 out of which are after the decimal point,
rate
- a decimal field of 6 digits, 2 out of which are after the decimal point,
time
- a field with date and time.
Mind the following requirements:
- No column can be a NULL.
- The columns
quantity
and rate
must be greater than zero.
- If no value is provided, the default
quantity
is 100.00.