[solved] database: conversion of CHARACTER Set
lazarus / 16-Databases

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Nicole · 2024-01-25 19:39

After having prinred my DLL, I discovered something, I do not enjoy:

one field:
  BEZEICHNUNG varchar(50) CHARACTER SET ISO8859_1 COLLATE DE_DE,

and another one:
  MYTEXT varchar(100) CHARACTER SET UTF8,

Probably it would be better to have only one Character Set and I would
prefer UTF8.
Is it possible to transport from ISO8859_1 to UTF8 without data-loss?

And if conversion is possible:
How can I do it?
Or would you rather recommend to take the ISO8859_1?

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Zvoni · 2024-01-26 07:58

Just add new columns (maybe even in a new table) with the "new"
Characterset/Collation, and throw all records at it.
If there is something wrong, the DB will complain

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kwyan · 2024-02-01 02:27

Suppose that table t has a column named BEZEICHNUNG defined as
VARCHAR(50) CHARACTER SET ISO8859_1 but you want to convert it to use
utf8mb4 so that you can store values from many languages. The
following statement accomplishes this:

Code: MySQL  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i ALTER TABLE
t MODIFY BEZEICHNUNG VARCHAR(50) CHARACTER SET utf8mb4;
https://dev.mysql.com/doc/refman/8.0/en/charset-conversion.html

Whether to use ISO8859_1 or UTF8MB4 depends on your application
design. One reason is: If you receive data from a screen where you
have no control over what characters can be accepted, UTF8MB4 may be a
good choice. If you have validation on the screen which only accepts
ISO8859_1 characers, you may choose this characer set.

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Zvoni · 2024-02-01 07:46

Quote from: kwyan on February 01, 2024, 03:27:54 amSuppose that table
t has a column named BEZEICHNUNG defined as VARCHAR(50) CHARACTER SET
ISO8859_1 but you want to convert it to use utf8mb4 so that you can
store values from many languages. The following statement accomplishes
this:

Code: MySQL  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i ALTER TABLE
t MODIFY BEZEICHNUNG VARCHAR(50) CHARACTER SET utf8mb4;
https://dev.mysql.com/doc/refman/8.0/en/charset-conversion.html

Whether to use ISO8859_1 or UTF8MB4 depends on your application
design. One reason is: If you receive data from a screen where you
have no control over what characters can be accepted, UTF8MB4 may be a
good choice. If you have validation on the screen which only accepts
ISO8859_1 characers, you may choose this characer set.
Nicole uses Firebird, not MySQL