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:

NULL Value
Special NULL Value
Non-NULL values
Character String, LOB Value (CLOB, BLOB), Number, Date Value, Time Value, Time Stamp Value, BOOLEAN

The non-NULL values can be specified using the syntax element data_type.

Structure

Syntax Syntax

<data_type> ::=
  CHAR[ACTER][(<unsigned_integer>)] [<ASCII | BYTE | UNICODE>]
| VARCHAR[(<unsigned_integer>)] [ASCII | BYTE | UNICODE]
| CLOB [ASCII | UNICODE]
| BLOB
| BOOLEAN
| FIXED(<unsigned_integer> [,<unsigned_integer>])
| FLOAT(<unsigned_integer>)
| INT[EGER]
| SMALLINT
| DATE
| TIME
| TIMESTAMP

End of the code.

For more information on ASCII, BYTE or UNICODE, see the section Code Attribute.

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 (data_type)
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 [ASCII]`	`CLOB`
`LONG BYTE`	`BLOB`
`LONG UNICODE`	`CLOB UNICODE`
`LONG VARCHAR`	`CLOB`
`NCHAR(p)`	`CHAR(p) UNICODE`
`NCLOB`	`CLOB UNICODE`
`NVARCHAR(p)`	`VARCHAR(p) UNICODE`
`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)`

More Information

Memory Requirements of a Column Value According to Data Type

SQL Tutorial, Converting Values