Data Type (data_type) 
A column definition (column_definition) can contain both the column name (column_name) and data types.
The following data types can be distinguished:
● Non-NULL values
Character string, LONG column, Number, Date value, Time value, Timestamp value, BOOLEAN
The non-NULL values can be specified using the syntax element data_type.
Syntax
<data_type> ::=
CHAR[ACTER]
[(<unsigned_integer>)] [ASCII | BYTE |
UNICODE]
| VARCHAR[(<unsigned_integer>)] [ASCII | BYTE |
UNICODE]
| LONG [VARCHAR]
[ASCII | BYTE | UNICODE]
| BOOLEAN
| FIXED(<unsigned_integer>
[,<unsigned_integer>])
| FLOAT(<unsigned_integer>)
| INT[EGER]
| SMALLINT4
| DATE |
TIME |
TIMESTAMP
A code attribute can also be specified for the following character strings (ASCII, BYTE, or UNICODE) as part of a column definition (column_definition) if necessary: CHAR[ACTER], VARCHAR, LONG[VARCHAR]
Examples
SQL Tutorial, 
Tables, Number Generator for a Single Column
of a Table
Explanation
In addition to the data types defined above, the following data types are also permitted in a column definition. The table below also indicates the way these are mapped to the above-mentioned data types.
Data Type |
Is Mapped To |
BINARY(p) |
FIXED(p) |
DEC[IMAL](p,s) |
FIXED(p,s) |
DEC[IMAL](p) |
FIXED(p) |
DEC[IMAL] |
FIXED(5) |
DOUBLE PRECISION |
FLOAT(38) |
FLOAT |
FLOAT(16) |
FLOAT(39..64) |
FLOAT(38) |
LONG VARCHAR |
LONG |
NUMERIC(p,s) |
FIXED(p,s) |
NUMERIC(p) |
FIXED(p) |
NUMERIC |
FIXED(5) |
REAL(p) |
FLOAT(p) |
REAL |
FLOAT(16) |
SERIAL |
FIXED(10) DEFAULT SERIAL |
SERIAL(p) |
FIXED(10) DEFAULT SERIAL(p) |
See also:
Memory Requirements of a Column Value According to Data Type
SQL Tutorial, Converting
Values