<data type> ::=
<character string type>
| <exact numeric type>
| <approximate numeric type>
<character string type> ::=
CHARACTER [(<lenght>)]
| CHAR [(<lenght>)]
<exact numeric type> ::=
NUMERIC [(<precision> [,<scale>])]
| DECIMAL [(<precision> [,<scale>])]
| DEC [(<precision> [,<scale>])]
| INTEGER
| INT
| SMALLINT
<approximate numeric type> ::=
FLOAT [(<precision>)]
| REAL
| DOUBLE PRECISION
<lenght> ::= <unsigned integer>
<precision> ::= <unsigned integer>
<scale> ::= <unsigned integer>