SQR has four scalar data types. The first three are numeric (variables begin with “#”), character string (variables begin with “$”), and date (variables begin with “$”, same as with character string variables.). Date variables must be declared, to be distinguished from character string variables. Numeric variables may be of more specific types: integer, floating point...). Database column variables begin with “&”. The values of database columns are set only by a SQL “select” statement; no other command can change their values.