Unicode support

With AQT v7 we have added Unicode support to AQT. This allows AQT to display text from non-European languages such as Chinese, Japanese, Korean, Arabic, Maori etc.

AQT v7 can not be run on Windows 95/98/ME as those versions of Windows do not support Unicode.

This support has been enabled by the following changes to AQT:

• most of the controls in AQT have been changed to new controls that support the display of Unicode characters
• the database interface layer has been changed to retrieve data in unicode format
• queries, and other files that AQT uses, are saved in unicode format if they contain unicode characters
• the copy, cut and paste functions have been amended to use unicode clipboard format.

Unicode support

By default, Unicode support is enabled within AQT. If you do not use Unicode data in your databases it is recommended that you switch this option off for two reasons:

• it may have a slight performance effect, and
• files are written in Unicode format, which you may not want.

Unicode support can be enabled / disabled with Unicode Options > Enable Unicode Support.

Changing to Unicode fonts

In addition to Enabling Unicode Support, display of many unicode characters is possible only if the font you are using can display these characters. By default, AQT uses MS Sans Serif font, which displays only some Unicode characters. Courier New displays a wider range of unicode characters; to display a wider range of unicode characters you may need a specialised font.

To use a differerent font, select it in Options > Unicode Options > Font used for Unicode controls. This setting applies to the Text boxes, Combo boxes and List boxes that are used to display values from the database.

In addition to this you may need to change other fonts:

• the font used in the syntax-highlighting text box used in the Run SQL window is set in Options > Syntax Highlighting
• the font used in the Data Display grids is set by (from the Data Display window) Edit > Set Font.
• the font used in the Database Explorer grids is set in Options > Table Information. You would only need to change this font if you have unicode characters in your table or column names.

Database interface

When Enable Unicode Support is selected, AQT will use different set of methods for interfacing to the database:

• all SQL will be passed to the database in unicode (rather than ASCII) format.
• all character data retreived from the database is retrieved in unicode format.
• all substitutional parameters passed to the database are passed in unicode format.

So far, all databases we have tested against support this unicode interface method (even if the databases themselves don't support unicode). However if you are having trouble accessing your database, disabling unicode support might provide a more reliable interface to the database.

Saved files

When Enable Unicode Support is selected, all files saved by AQT are scanned for unicode characters. If any unicode characters are found, AQT will save the file in unicode format.

Files saved in unicode format can be read only by external editors that support unicode (such as Notepad). Unicode files are in double-byte format with the first two characters being x'FFFE'.

The Audit files are not saved in unicode format.

Exporting data

• unicode data can be exported to Excel (as Excel supports unicode data).
• when exporting data as HTML, any unicode characters will be written using the unicode HTML tags.
• when exporting data as Insert statements, you have the option to Export Data in Unicode format. When this option is selected, the insert SQL script is saved in unicode format if it contains any unicode characters. If you are going to run the script using an SQL processor that does not support unicode text, you should de-select this option.

If you select append when exporting data, AQT will ignore the Export Data in Unicode format setting and will maintain the existing file format. For instance, if the existing file is non-unicode, all subsequent data will be appended to the file in non-unicode format, even if the data contains unicode characters. It is not possible to mix the character encoding within a file.

Writing CLOBs to files

When Unicode support is enabled, CLOBs written to files (using the Options > LOB Options > Send to files option) will be written as unicode files.

Demo Table

In the demo database AQTDEMO is a table unicode_table containining Unicode data. Displaying this table is a good test of whether unicode display is working on your PC.

Creating Unicode characters

Unless you have a specialised keyboard, unicode characters can be created with:

• from the AQT Database Explorer, click on Tools > Unicode Character map
• Windows supplies a very good unicode character map. It can be run by Start > Run and running charmap

Limitations with Unicode

Current limitations are:

• printing the data grid does not print unicode characters. We have raised this problem with the developers of the grid. In the meantime you can print your unicode data by exporting to HTML or Excel and printing from these.
• only the export methods given in the previous section will export unicode data.

Database support

Not all databases support Unicode data, and the degree to which they support unicode varies from one database to another. In the following topics we describe how particular databases support unicode.