Unicode Data Storage

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# Unicode Data Storage

This document covers the following topics:

- Unicode Data/Parameter Access

- Database Management System Interfaces

- Work Files and Print Files

## Unicode Data/Parameter Access

The following graphic shows how Unicode data and parameters are accessed.

## Database Management System Interfaces

### Accessing Unicode Data in an Adabas Database

Natural enables users to access wide-character fields (format W) in an Adabas database.

> Data Definition Module

>   Adabas wide-character fields (W) are mapped to the Natural data format U (Unicode).

> Access Configuration

>   Natural receives data from Adabas and sends data to Adabas using UTF-16 as common encoding.

>   This encoding is specified with the `OPRB` parameter and is sent to Adabas with the open request. It is used for wide-character fields and applies to the entire Adabas user session.

For detailed information, see Unicode Data in the Accessing Data in an Adabas Database part of the Programming Guide.

## Work Files and Print Files

The following topics are covered below:

- WRITE WORK FILE

- READ WORK FILE

- Special Considerations for Work File Type Transfer

- Print Files

### WRITE WORK FILE

The information below applies for the statement `WRITE WORK FILE`. See the Statements documentation for detailed information on this statement.

#### Code Page Data

The following work file types write code page data:

- ASCII and ASCII compressed

- Unformatted

- CSV

- Entire Connection

The work file type and the code page must be defined in the Configuration Utility. For further information, see Work Files in the Configuration Utility documentation.

All Natural data defined with the operands A (alphanumeric) and U (Unicode) are converted to the specified code page. If a code page has not been specified, all data are converted to the default code page which is defined with the `CP` parameter.

Note
In the work file, all written A and U operand data are in code page format.

If U operand data are to be written into these work files and afterwards read from these work files without loss of data, you have to define UTF-8 as the code page (in the Configuration Utility). In this case, all A and U operand data are written in UTF-8 format. A subsequent `READ WORK FILE` statement where the work file is also configured using code page UTF-8 reads the operand U data without loss of data.

Notes:

1. Work file data which have been written in UTF-8 format can be read by text editors which support UTF-8 (for example, Notepad on the Windows platform).
2. Natural data defined with the operand B (binary) are not converted to the code page which has been specified in the Configuration Utility. These data are written as they are stored in Natural, without any code page conversion.

If one of the above-mentioned work file types is specified and the code page UTF-8 is defined for the work file, the work file attributes `BOM` (write byte order mark) and `NOBOM` (do not write byte order mark) take effect. These attributes can be specified in the Work Files category of the Configuration Utility and with the `DEFINE WORK FILE` statement. If the code page UTF-8 is defined for the work file and the work file attribute `BOM` is specified, the UTF-8 byte order mark (hexadecimal representation: `H'EFBBBF'`) is written at the beginning of the work file, in front of the work file data.

If a work file type other than the above-mentioned work file types is used for writing the work file, or if a code page other than UTF-8 is defined for the work file, the specification of the attribute `BOM` is ignored during runtime. The following table shows the runtime behavior during the processing of the statements `WRITE WORK FILE` and `READ WORK FILE`:

Code Page and Attribute Setting | `WRITE WORK FILE` | `READ WORK FILE`
--- | --- | ---
The code page UTF-8 is not specified for the work file (default). The work file attributes `BOM` and `NOBOM` have no effect. | No UTF-8 byte order mark is written. No conversion to UTF-8. | No check for UTF-8 byte order mark. No conversion from UTF-8.
The code page UTF-8 is specified for the work file. The work file attribute `BOM` is specified. | UTF-8 byte order mark is written. A and U fields are converted to UTF-8. | Check for UTF-8 byte order mark. If an UTF-8 byte order mark is found, it is removed from the work file data. A fields are converted from UTF-8 to the default code page. U fields are converted from UTF-8 to the Natural internal runtime representation UTF-16.
The code page UTF-8 is specified for the work file. The work file attribute `NOBOM` (default) is specified. | No UTF-8 byte order mark is written. A and U fields are converted to UTF-8. | Check for UTF-8 byte order mark. If an UTF-8 byte order mark is found, it is removed from the work file data. A fields are converted from UTF-8 to the default code page. U fields are converted from UTF-8 to the Natural internal runtime representation UTF-16.

#### Binary Data

The following work file types write binary data (for example, UTF-16 for operand format U):

- SAG

- Portable

Natural data defined with the operands A and U are not converted to code page. These data are written to the work file in binary format. For U operand data, this is done in UTF-16.

### READ WORK FILE

The information below applies for the statement `READ WORK FILE`. See the Statements documentation for detailed information on this statement. Take note of the restrictions that are listed for the `RECORD` option.

#### Code Page Data

When the following work file types are used, the work file data that are read into Natural U (Unicode) operands are converted from the specified code page to UTF-16.

- ASCII and ASCII compressed

- Unformatted

- CSV

- Entire Connection

Data that are read into A (alphanumeric) operands are converted, if required, from the specified code page to the default code page which has been defined with the parameter `CP`.

If one of the above-mentioned work file types is specified and the code page UTF-8 is defined for the work file, the `READ WORK FILE` statement automatically checks the work file for an UTF-8 byte order mark. If an UTF-8 byte order mark is found at the beginning of the work file, it is removed. The data that are read from the work file are converted from UTF-8 to the default code page.

If data are read from another work file type, the check for a byte order mark is not performed and a byte order mark is therefore not removed.

For information on the runtime behavior during the processing of the statements `WRITE WORK FILE` and `READ WORK FILE`, see the table in the previous section.

#### Binary Data

When the following work file types are used, the work file data are read into the Natural operands A and U without conversion (that is: they are read in binary format):

- SAG

- Portable

The work file type Portable supports endian conversion for data of operand format U.

### Special Considerations for Work File Type Transfer

Operand format U is generally supported for the work file type Transfer. If Entire Connection is not able to read or write Unicode for the selected file type, a runtime error message is displayed.

### Print Files

The handling for Unicode data in print files depends on the selected logical device’s (LPT1 to LPT31) print method, currently either GUI (Windows only) or TTY.

Regardless of the print method, data are passed to the Natural printing services in UTF-16 format. That is, any format A field data will already have been converted to Unicode.

#### GUI Print Method

With this Windows-only print method, the data are passed to the Windows printer driver in Unicode (UTF-16) format. Because this is the standard method for printing data in Windows, the driver invariably handles this data appropriately. This is therefore the recommended print method under Windows if any characters that are not within the system code page are being used.

#### TTY Print Method

With this print method, the data are, by default, converted from the internal (UTF-16) format into the system code page. However, by using a printer profile, it is possible to specify that the data should instead either be converted into UTF-8 format, or be subjected to an additional conversion to an arbitrary external code page. For more information on these alternatives, see Printer Profiles in the Configuration Utility documentation.

The rationale behind the default behavior of converting the data into the system code page is based on the current lack of printers capable of directly accepting raw text files in UTF-8 format.

### On this page

- Unicode Data/Parameter Access
- Database Management System Interfaces
- Work Files and Print Files