How can I upgrade Firebird for the Unicode Data?

问题

I'm using Firebird 2.5.1 with normal Varchar... then i'd like to upgrade all data using Unicode (to access Delphi XE2, DBExpress) I searched but not good help.. So could you advice me how to upgrade my data to unicode firebird? thanks a lot... and have a nice day.

回答1:

You can take a look at IBExpert migration or use tools like fbclone

回答2:

In Firebird you have to specify a character-set for every varchar-field. So there is no "normal" varchar. If you don't specify it explicitly in your CREATE TABLE-statement Firebird uses the default character-set of your database.
There are a few available character-sets in Firebird. Probably you meant ASCII or an ISO-Charset with "normal". Beside these chacsets Firebirds supports UNICODE_FSS or UTF8. It is possible to change the character-set of the fields in your DB.
First you have to find out which id your prefered character-set uses. To do that you can look in the table RDB$CHARACTER_SETS
After that you need to find out which domain is used by the column you want to change. If you don't specify a custom-domain in your CREATE TABLE-statement Firebird generates one for every column.
Than could you change the used character-set for this domain in the system-table.

update RDB$FIELDS T1
  set T1.RDB$CHARACTER_SET_ID = 4
  where RDB$FIELD_NAME = (select RDB$FIELD_SOURCE 
                            from RDB$RELATION_FIELDS T2 
                            where T2.RDB$RELATION_NAME = 'NEW_TABLE' 
                              and T2.RDB$FIELD_NAME = 'NEW_FIELD')

Alternativly you could look for all varchar-domains in the system-tables and change it with one single-statement.

回答3:

You could use following approach:

Scan every table in a database for string fields
For every string field create additional one using unicode character set
Copy data between fields
Drop original field
Rename temporary field

Below is an example of a code for data conversion:

EXECUTE BLOCK
AS
  DECLARE VARIABLE fn CHAR(31) CHARACTER SET UNICODE_FSS;
  DECLARE VARIABLE rn CHAR(31) CHARACTER SET UNICODE_FSS;
  DECLARE VARIABLE cl INTEGER;
BEGIN
  FOR
    SELECT 
      r.rdb$field_name, 
      r.rdb$relation_name, 
      f.rdb$character_length
    FROM 
      rdb$relation_fields r JOIN rdb$fields f
        ON f.rdb$field_name = r.rdb$field_source
    WHERE 
      f.rdb$character_set_id >= 10 
        AND f.rdb$character_length > 0
        AND f.rdb$field_sub_type IS NULL
    INTO :fn, :rn, :cl
  DO BEGIN
    EXECUTE STATEMENT 'ALTER TABLE "' || :rn ||
      '" ADD unique_temp_field_name VARCHAR(' || :cl ||
      ') CHARACTER SET UNICODE_FSS'
    WITH AUTONOMOUS TRANSACTION;

    EXECUTE STATEMENT 'UPDATE "' || :rn ||
      '" SET unique_temp_field_name = "' || :fn || '"'
    WITH AUTONOMOUS TRANSACTION;

    EXECUTE STATEMENT 'ALTER TABLE "' || :rn || '" DROP "' || :fn || '"'
    WITH AUTONOMOUS TRANSACTION;

    EXECUTE STATEMENT 'ALTER TABLE "' || :rn || 
      '" ALTER unique_temp_field_name TO ' ||
      '"' || :fn || '"'
    WITH AUTONOMOUS TRANSACTION;
  END
END

For real world application this code should be modified in order to:

Transfer fields constraints and defaults
Drop and then restore PK, FK, indices which use field being converted
Drop and the recreate any trigger or stored procedure which depends on a field being converted

来源：https://stackoverflow.com/questions/8012300/how-can-i-upgrade-firebird-for-the-unicode-data

标签

unicode

firebird