The Character Value Table

The Character Value Table

A Character Value Table is a list of characters that are indexed by Calm. Once a character has been indexed by Calm it may then be used as part of a search term. By default, search terms may only include letters (including accented characters such as ü), numbers (0–9), the underscore (_) or the apostrophe ('). To allow other characters, such as punctuation characters, to be used in terms, you may use a Character Value Table containing those characters when you re-index your Calm databases.

Using a Character Value Table

Calm contains a character value table which is available for you to use in re-indexing if you require one. It contains a character value (in the range 0 to 63) for each indexable character. Two or more characters can have the same value, for example “A”, “a” and “á” might all have the value 10. All characters with the same value are considered to be identical. Please note that this default Character Value Table assumes that when you search for a term containing an accented character, for example: é, you will also wish to see examples of the term that contains the unaccented character. To re-index using this Character Value Table:

• Open the Admin program
  Open the database you wish to re-index, select Reindex from the File drop down menu
• Underneath the Character Value Table box, click on the Browse button, you will be given the opportunity to search for a file

• Navigate to the Dscribe/Archive/Db folder and select the file Wordlist.cvt.

Customising the character value table

You may customise the default Character Value Table by adding or removing indexable characters, for example if you wish to index Scandinavian, Greek or Arabic text. To customise the table, you must edit the Wordlist.cvt file. This file contains 64 lines, numbered 0 to 63. Each line contains a list of characters, separated from the number by blanks or tabs. Some lines are left “empty”, meaning that the value has no corresponding characters. Any lines starting with a semi-colon are comments/notes. To edit the Wordlist.cvt file:

• Open the Admin program
  Open a database and select Reindex from the File drop down menu
• Underneath the Character Value Table box, click on the button
• Insert any new characters you wish to index on the appropriate line. Please note that characters on the same line are considered to be identical by the indexing engine

• Remove any characters that you do not want to be indexed from the file

Please note that every time you make a change to the Character Value Table, you are changing the rules by which Calm indexes its databases. You will therefore have to re-index any databases that use the Character Value Table before the changes will take effect.

Creating a New Character Value Table

You may also create a new Character Value Table of your own against which to re-index Calm by creating a new .cvt file to use instead of the existing Wordlist.cvt.

A .cvt file typically contains 64 lines, numbered 0 to 63. Each line can contain a list of characters, separated from the number by blanks or tabs. Lines can be left “empty”, meaning that the value has no corresponding characters. Any lines starting with a semi-colon are comments/notes. To create a new .cvt file:

• Exit from Calm and run Windows Notepad.
• Type the numbers 0 to 63 in a column on the left-hand side.
• Type the index character(s) on one of the numbered lines. All characters on the same line are considered to be identical by the indexing engine. It is best to spread the characters evenly over the 0 to 63 range of values, as this should give better indexing performance.

If the character is not available from the keyboard:

• Press the Num Lock key to activate the Number Lock facility on your keyboard

• Press and hold down the Alt key.
• Type the ANSI code of the character Please Note that Calm does not allow characters with codes less than 33 to be extra index characters.

To save your new Character Value Table:

• Click Save As from the File drop down menu and save the file on your PC or on the Calm server. (Please Note that the usual location for the Character Value Table is in the Dscribe/Archive/Db folder)
  Type a new filename for the customised character value table, with a .cvt extension, in the File name box, for example: Arabic.cvt, and click OK.
   
• Click Exit from the File drop down menu.

To use your new Character Value Table the next time you re-index:

• Open the Admin program
  Open the database you wish to re-index and select Reindex from the File drop down menu
• Underneath the Character Value Table box, click on the Browse button, you will be given the opportunity to search for a file

• Navigate to the folder where you saved your new Character Value Table and select it
• Click OK to re-index