Data Types 
For most Loader commands for exporting and importing data, you can specify the data type that the relevant field values in the data stream has or should have. A distinction is made between database-internal and external data types. The external data type and the corresponding internal database data type of the column value in the target table do not have to be identical.
Internal Database Data Types
Internal database data types are the data types defined for the columns in the database table. For an explanation of the internal database data types, see SQL Reference Manual, Data Type (data_type).
External Data Types
External data types are either the data types into which Loader can convert internal database data types when it exports application data or the data types that Loader converts into internal database data types when it imports data. You can specify the external data type for each field value to be exported or imported in the Loader commands for exporting or importing using syntax element field_type.
Structure
Syntax
<field_type> ::= /* empty */ | CHAR | DECIMAL [<unsigned_integer>] | INTEGER | REAL | ZONED [<unsigned_integer>]
/* empty */ |
The data field is read or output as data type CHAR. Each internal database column format in the database can be read and output in CHAR format. |
CHAR |
ASCII, UCS2, or UTF8-coded, depending on the computer, max. 254 bytes. |
DECIMAL [<unsigned_integer>] |
Packed decimally: one digit per half byte, sign in extreme right half byte, 1 to 10 bytes, maximum of 18 digits, the position of the decimal point is derived from the table column type unsigned_integer: number of digits to the right of the decimal point |
INTEGER |
Binary coded (computer-specific), 1, 2, or 4 bytes, sign in bit 0, negative values in two's complement notation |
REAL |
Floating point notation with mantissa and exponent, 4 or 8 bytes, in computer-specific notation |
ZONED [<unsigned_integer>] |
Zoned decimal: /370 zoned data format is permitted, the position of the decimal point is derived from the type of the table column unsigned_integer: number of digits to the right of the decimal point |
If no external data type is specified for a field value, Loader selects CHAR data type as the default for this field value. Therefore, if the field value does not have data type CHAR or data type CHAR is not required, you need to specify the data type.
Binary Values
All numeric, external data types (INTEGER, REAL, DECIMAL, ZONED) are interpreted as binary values. These can be converted to any of the internal data types (FIXED, SMALLINT, INTEGER, FLOAT) used by the database.
Loader always interprets data of data type INTEGER as signed values. You can adjust how this data is represented in a data stream using the syntax element int_spec (see: Data Format).
Data of data type REAL is coded in a computer-specific format and cannot be transported between different operating systems and computer platforms without being converted again.
Plain Text Values
Field values with external data type CHAR are plain text values, that is, these values consist of readable characters.
Plain text values can conform to different specifications: ASCII, UCS2, or UTF8 (see: Code Specification).
You can specify the data formats for plain text values that represent the date, time, or a time stamp (see date, time and time stamp specification).
HEX Values
You can use an external data type with the additional specification HEX (see: Column Description, Output Column) as a hexadecimal value. This enables you to import or export all data types in hexadecimal form. Each byte of data in the result is represented by two hexadecimal numbers. Each value in the data stream occupies twice as much space as the value of the same data type that is not specified as a HEX value.
Converting the Data Types
The specification of the data types tells Loader how to interpret the data in the data stream.
If application data is exported from a table, the internal database data types are converted to the specified external data types and the corresponding column values are exported.
If application data is imported into a table, the specified external data types are converted to internal database data types and the corresponding column values of a table are imported.
Loader can convert numeric data types. You can use the external data type CHAR to read or output any internal database data type.
If data is exported from a table, the internal database data types are converted to the specified external data types and the corresponding column values are exported. The database-internal data types INT[EGER], FIXED and SMALLINT can be transported to the external data types DECIMAL, INTEGER, REAL or ZONED. The database-internal data type FLOAT can be converted to the external data types CHAR[ACTER] or REAL.
When data is imported into a table, the specified external data types are converted to internal database data types and the corresponding column values of a table are imported. The external data types DECIMAL, INTEGER, REAL and ZONED can be converted to the database-internal data types INTEGER, FIXED, FLOAT or SMALLINT.
Example
Example
IMPORT TABLE hotel.reservation
DATA INSTREAM 'reservation_fwv.data' FWV BINARY
rno 01-04 INTEGER
cno 05-08 INTEGER
hno 09-12 INTEGER
type 13-18 CHAR
arrival 19-28 CHAR
departure 29-38 CHAR
The database table RESERVATION requires the internal database data type FIXED for the values in columns RNO, CNO and HNO. The IMPORT TABLE command defines the external data type INTEGER for these columns. The data in the columns RNO, CNO and HNO is converted to the internal database data type FIXED when it is imported.
Example
IMPORT TABLE hotel.room
DATA INSTREAM 'room_fwv_binary.data' FWV BINARY
hno 01-05
type 06-11
free 12-19 INTEGER HEX
price 20-27 INTEGER HEX
The IMPORT TABLE command defines hexadecimal values FREE and PRICE as the external data type using the additional HEX specification.