Postgresql 中文操作指南

24.3. Character Set Support #

PostgreSQL 中的字符集支持允许您以各种字符集（也称为编码）存储文本，包括单字节字符集，如 ISO 8859 系列，和多字节字符集，如 EUC（扩展 Unix 代码）、UTF-8 和 Mule 内部代码。所有受支持的字符集都可以由客户端透明地使用，但是，少数字符集不受服务器内使用（即，作为服务器端编码）的支持。使用 initdb 初始化 PostgreSQL 数据库集群时选择默认字符集。当您创建数据库时可以覆盖它，因此您可以拥有多个具有不同字符集的数据库。

The character set support in PostgreSQL allows you to store text in a variety of character sets (also called encodings), including single-byte character sets such as the ISO 8859 series and multiple-byte character sets such as EUC (Extended Unix Code), UTF-8, and Mule internal code. All supported character sets can be used transparently by clients, but a few are not supported for use within the server (that is, as a server-side encoding). The default character set is selected while initializing your PostgreSQL database cluster using initdb. It can be overridden when you create a database, so you can have multiple databases each with a different character set.

但是，一个重要的限制是每个数据库的字符集必须与其 LC_CTYPE（字符分类）和 LC_COLLATE（字符串排序顺序）区域设置兼容。对于 C 或 POSIX 区域设置，允许任何字符集，但对于 libc 提供的其他区域设置，只有唯一一个字符集将正确工作。（但是，在 Windows 中，UTF-8 编码可以与任何区域设置一起使用。）如果您配置了 ICU 支持，可以使用 ICU 提供的区域设置配合大部分而非全部服务器端编码。

An important restriction, however, is that each database’s character set must be compatible with the database’s LC_CTYPE (character classification) and LC_COLLATE (string sort order) locale settings. For C or POSIX locale, any character set is allowed, but for other libc-provided locales there is only one character set that will work correctly. (On Windows, however, UTF-8 encoding can be used with any locale.) If you have ICU support configured, ICU-provided locales can be used with most but not all server-side encodings.

24.3.1. Supported Character Sets #

Table 24.3显示了 PostgreSQL 中可供使用的字符集。

Table 24.3 shows the character sets available for use in PostgreSQL.

Table 24.3. PostgreSQL Character Sets

Name

Description

Language

Server?

ICU?

Bytes/Char

Aliases

BIG5

Big Five

Traditional Chinese

1–2

WIN950, Windows950

EUC_CN

Extended UNIX Code-CN

Simplified Chinese

Yes

1–3

EUC_JP

Extended UNIX Code-JP

Japanese

Yes

1–3

EUC_JIS_2004

Extended UNIX Code-JP, JIS X 0213

Japanese

Yes

1–3

EUC_KR

Extended UNIX Code-KR

Korean

Yes

1–3

EUC_TW

Extended UNIX Code-TW

Traditional Chinese, Taiwanese

Yes

1–3

GB18030

National Standard

Chinese

1–4

GBK

Extended National Standard

Simplified Chinese

1–2

WIN936, Windows936

ISO_8859_5

ISO 8859-5, ECMA 113

Latin/Cyrillic

Yes

ISO_8859_6

ISO 8859-6, ECMA 114

Latin/Arabic

Yes

ISO_8859_7

ISO 8859-7, ECMA 118

Latin/Greek

Yes

ISO_8859_8

ISO 8859-8, ECMA 121

Latin/Hebrew

Yes

JOHAB

JOHAB

Korean (Hangul)

1–3

KOI8R

KOI8-R

Cyrillic (Russian)

Yes

KOI8

KOI8U

KOI8-U

Cyrillic (Ukrainian)

Yes

LATIN1

ISO 8859-1, ECMA 94

Western European

Yes

ISO88591

LATIN2

ISO 8859-2, ECMA 94

Central European

Yes

ISO88592

LATIN3

ISO 8859-3, ECMA 94

South European

Yes

ISO88593

LATIN4

ISO 8859-4, ECMA 94

North European

Yes

ISO88594

LATIN5

ISO 8859-9, ECMA 128

Turkish

Yes

ISO88599

LATIN6

ISO 8859-10, ECMA 144

Nordic

Yes

ISO885910

LATIN7

ISO 8859-13

Baltic

Yes

ISO885913

LATIN8

ISO 8859-14

Celtic

Yes

ISO885914

LATIN9

ISO 8859-15

LATIN1 with Euro and accents

Yes

ISO885915

LATIN10

ISO 8859-16, ASRO SR 14111

Romanian

Yes

ISO885916

MULE_INTERNAL

Mule internal code

Multilingual Emacs

Yes

1–4

SJIS

Shift JIS

Japanese

1–2

Mskanji, ShiftJIS, WIN932, Windows932

SHIFT_JIS_2004

Shift JIS, JIS X 0213

Japanese

1–2

SQL_ASCII

unspecified (see text)

any

Yes

UHC

Unified Hangul Code

Korean

1–2

WIN949, Windows949

UTF8

Unicode, 8-bit

all

Yes

1–4

Unicode

WIN866

Windows CP866

Cyrillic

Yes

ALT

WIN874

Windows CP874

Thai

Yes

WIN1250

Windows CP1250

Central European

Yes

WIN1251

Windows CP1251

Cyrillic

Yes

WIN

WIN1252

Windows CP1252

Western European

Yes

WIN1253

Windows CP1253

Greek

Yes

WIN1254

Windows CP1254

Turkish

Yes

WIN1255

Windows CP1255

Hebrew

Yes

WIN1256

Windows CP1256

Arabic

Yes

WIN1257

Windows CP1257

Baltic

Yes

WIN1258

Windows CP1258

Vietnamese

Yes

ABC, TCVN, TCVN5712, VSCII

并非所有客户端 API 都支持所有列出的字符集。例如，PostgreSQL JDBC 驱动程序不支持 MULE_INTERNAL、LATIN6、LATIN8 和 LATIN10。

Not all client APIs support all the listed character sets. For example, the PostgreSQL JDBC driver does not support MULE_INTERNAL, LATIN6, LATIN8, and LATIN10.

SQL_ASCII 设置的行为与其他设置的行为有很大不同。当服务器字符集为 SQL_ASCII 时，服务器将按照 ASCII 标准解释字节值 0 至 127，而将字节值 128 至 255 作为未解释的字符。设置 SQL_ASCII 时不会执行任何编码转换。因此，这个设置并不那么明确地声明使用某种特定编码，而只是声明不知道编码。在大多数情况下，如果您使用的是任何非 ASCII 数据，则不建议使用 SQL_ASCII 设置，因为 PostgreSQL 无法通过转换或验证非 ASCII 字符来帮助您。

The SQL_ASCII setting behaves considerably differently from the other settings. When the server character set is SQL_ASCII, the server interprets byte values 0–127 according to the ASCII standard, while byte values 128–255 are taken as uninterpreted characters. No encoding conversion will be done when the setting is SQL_ASCII. Thus, this setting is not so much a declaration that a specific encoding is in use, as a declaration of ignorance about the encoding. In most cases, if you are working with any non-ASCII data, it is unwise to use the SQL_ASCII setting because PostgreSQL will be unable to help you by converting or validating non-ASCII characters.

24.3.2. Setting the Character Set #

initdb 用于定义 PostgreSQL 集群的默认字符集（编码）。例如：

initdb defines the default character set (encoding) for a PostgreSQL cluster. For example,

initdb -E EUC_JP

将默认字符集设置为 EUC_JP（日语的扩展 Unix 代码）。您可以使用 —encoding 而不是 -E（如果您喜欢更长的选项字符串）。如果未提供 -E 或 —encoding 选项，initdb 将尝试根据指定的或默认区域设置确定要使用的适当编码。

sets the default character set to EUC_JP (Extended Unix Code for Japanese). You can use —encoding instead of -E if you prefer longer option strings. If no -E or —encoding option is given, initdb attempts to determine the appropriate encoding to use based on the specified or default locale.

您可以在创建数据库时指定非默认编码，前提是该编码与选定的区域设置兼容：

You can specify a non-default encoding at database creation time, provided that the encoding is compatible with the selected locale:

createdb -E EUC_KR -T template0 --lc-collate=ko_KR.euckr --lc-ctype=ko_KR.euckr korean

这会创建一个名为 korean 的数据库，该数据库使用字符集 EUC_KR 和区域设置 ko_KR。完成此操作的另一种方法是使用以下 SQL 命令：

This will create a database named korean that uses the character set EUC_KR, and locale ko_KR. Another way to accomplish this is to use this SQL command:

CREATE DATABASE korean WITH ENCODING 'EUC_KR' LC_COLLATE='ko_KR.euckr' LC_CTYPE='ko_KR.euckr' TEMPLATE=template0;

请注意，上述命令指定复制 _template0_数据库。在复制任何其他数据库时，不能将编码和语言环境设置从源数据库的设置更改为其他设置，因为这可能会导致数据损坏。有关详细信息，请参阅 Section 23.3。

Notice that the above commands specify copying the template0 database. When copying any other database, the encoding and locale settings cannot be changed from those of the source database, because that might result in corrupt data. For more information see Section 23.3.

数据库的编码存储在系统目录 pg_database 中。您可以使用 psql -l 选项或 \l 命令查看它。

The encoding for a database is stored in the system catalog pg_database. You can see it by using the psql -l option or the \l command.

$ psql -l
                                         List of databases
   Name    |  Owner   | Encoding  |  Collation  |    Ctype    |          Access Privileges
-----------+----------+-----------+-------------+-------------+-------------------------------------
 clocaledb | hlinnaka | SQL_ASCII | C           | C           |
 englishdb | hlinnaka | UTF8      | en_GB.UTF8  | en_GB.UTF8  |
 japanese  | hlinnaka | UTF8      | ja_JP.UTF8  | ja_JP.UTF8  |
 korean    | hlinnaka | EUC_KR    | ko_KR.euckr | ko_KR.euckr |
 postgres  | hlinnaka | UTF8      | fi_FI.UTF8  | fi_FI.UTF8  |
 template0 | hlinnaka | UTF8      | fi_FI.UTF8  | fi_FI.UTF8  | {=c/hlinnaka,hlinnaka=CTc/hlinnaka}
 template1 | hlinnaka | UTF8      | fi_FI.UTF8  | fi_FI.UTF8  | {=c/hlinnaka,hlinnaka=CTc/hlinnaka}
(7 rows)

Important

在大多数现代操作系统上，PostgreSQL 可以确定 LC_CTYPE 设置所暗示的字符集，并且它将强制只使用匹配的数据库编码。在较旧的系统上，您有责任确保您使用的编码与您选择的区域设置预期的一致。此处的错误很可能会导致区域设置相关操作（例如排序）出现奇怪的行为。

On most modern operating systems, PostgreSQL can determine which character set is implied by the LC_CTYPE setting, and it will enforce that only the matching database encoding is used. On older systems it is your responsibility to ensure that you use the encoding expected by the locale you have selected. A mistake in this area is likely to lead to strange behavior of locale-dependent operations such as sorting.

即使 LC_CTYPE 不是 C 或 POSIX，PostgreSQL 也允许超级用户创建使用 SQL_ASCII 编码的数据库。如上所述，SQL_ASCII 并不强制存储在数据库中的数据采用任何特定编码，因此这种选择构成了区域设置相关错误行为的风险。不建议使用此设置组合，将来可能会完全禁止这种组合。

PostgreSQL will allow superusers to create databases with SQL_ASCII encoding even when LC_CTYPE is not C or POSIX. As noted above, SQL_ASCII does not enforce that the data stored in the database has any particular encoding, and so this choice poses risks of locale-dependent misbehavior. Using this combination of settings is deprecated and may someday be forbidden altogether.

24.3.3. Automatic Character Set Conversion Between Server and Client #

对于许多字符集的组合，PostgreSQL 支持在服务器和客户端之间进行自动字符集转换（ Section 24.3.4显示了哪些字符集支持转换）。

PostgreSQL supports automatic character set conversion between server and client for many combinations of character sets (Section 24.3.4 shows which ones).

要启用自动字符集转换，您必须告诉 PostgreSQL 您要在客户端使用的字符集（编码）。有几种方法可以做到这一点：

To enable automatic character set conversion, you have to tell PostgreSQL the character set (encoding) you would like to use in the client. There are several ways to accomplish this:

如果无法转换某个特定字符（假设您针对服务器选择了 EUC_JP 而针对客户端选择了 LATIN1，且返回了一些在 LATIN1 中没有表示的日语字符），则会报告错误。

If the conversion of a particular character is not possible — suppose you chose EUC_JP for the server and LATIN1 for the client, and some Japanese characters are returned that do not have a representation in LATIN1 — an error is reported.

如果客户端字符集定义为 SQL_ASCII，则无论服务器的字符集是什么，编码转换都会被禁用。（但是，如果服务器的字符集不是 SQL_ASCII，则服务器仍然会检查传入的数据是否针对该编码有效；因此，产生的净效果就像客户端字符集与服务器字符集相同一样。）与服务器一样，除非您使用全 ASCII 数据，否则不建议使用 SQL_ASCII。

If the client character set is defined as SQL_ASCII, encoding conversion is disabled, regardless of the server’s character set. (However, if the server’s character set is not SQL_ASCII, the server will still check that incoming data is valid for that encoding; so the net effect is as though the client character set were the same as the server’s.) Just as for the server, use of SQL_ASCII is unwise unless you are working with all-ASCII data.

24.3.4. Available Character Set Conversions #

PostgreSQL 允许在两个字符集之间进行转换，这些字符集的转换函数已列入 pg_conversion 系统目录。PostgreSQL 随附一些预定义转换，如 Table 24.4 中总结所述，并在 Table 24.5 中详细显示。您可使用 SQL 命令 CREATE CONVERSION 创建新转换。（要用于自动的客户端/服务器转换，必须将其字符集对的转换标记为“默认”。）

PostgreSQL allows conversion between any two character sets for which a conversion function is listed in the pg_conversion system catalog. PostgreSQL comes with some predefined conversions, as summarized in Table 24.4 and shown in more detail in Table 24.5. You can create a new conversion using the SQL command CREATE CONVERSION. (To be used for automatic client/server conversions, a conversion must be marked as “default” for its character set pair.)

Table 24.4. Built-in Client/Server Character Set Conversions

Server Character Set

Available Client Character Sets

BIG5

not supported as a server encoding

EUC_CN

EUC_CN, MULE_INTERNAL, UTF8

EUC_JP

EUC_JP, MULE_INTERNAL, SJIS, UTF8

EUC_JIS_2004

EUC_JIS_2004, SHIFT_JIS_2004, UTF8

EUC_KR

EUC_KR, MULE_INTERNAL, UTF8

EUC_TW

EUC_TW, BIG5, MULE_INTERNAL, UTF8

GB18030

not supported as a server encoding

GBK

not supported as a server encoding

ISO_8859_5

ISO_8859_5, KOI8R, MULE_INTERNAL, UTF8, WIN866, WIN1251

ISO_8859_6

ISO_8859_6, UTF8

ISO_8859_7

ISO_8859_7, UTF8

ISO_8859_8

ISO_8859_8, UTF8

JOHAB

not supported as a server encoding

KOI8R

KOI8R, ISO_8859_5, MULE_INTERNAL, UTF8, WIN866, WIN1251

KOI8U

KOI8U, UTF8

LATIN1

LATIN1, MULE_INTERNAL, UTF8

LATIN2

LATIN2, MULE_INTERNAL, UTF8, WIN1250

LATIN3

LATIN3, MULE_INTERNAL, UTF8

LATIN4

LATIN4, MULE_INTERNAL, UTF8

LATIN5

LATIN5, UTF8

LATIN6

LATIN6, UTF8

LATIN7

LATIN7, UTF8

LATIN8

LATIN8, UTF8

LATIN9

LATIN9, UTF8

LATIN10

LATIN10, UTF8

MULE_INTERNAL

MULE_INTERNAL, BIG5, EUC_CN, EUC_JP, EUC_KR, EUC_TW, ISO_8859_5, KOI8R, LATIN1 to LATIN4, SJIS, WIN866, WIN1250, WIN1251

SJIS

not supported as a server encoding

SHIFT_JIS_2004

not supported as a server encoding

SQL_ASCII

any (no conversion will be performed)

UHC

not supported as a server encoding

UTF8

all supported encodings

WIN866

WIN866, ISO_8859_5, KOI8R, MULE_INTERNAL, UTF8, WIN1251

WIN874

WIN874, UTF8

WIN1250

WIN1250, LATIN2, MULE_INTERNAL, UTF8

WIN1251

WIN1251, ISO_8859_5, KOI8R, MULE_INTERNAL, UTF8, WIN866

WIN1252

WIN1252, UTF8

WIN1253

WIN1253, UTF8

WIN1254

WIN1254, UTF8

WIN1255

WIN1255, UTF8

WIN1256

WIN1256, UTF8

WIN1257

WIN1257, UTF8

WIN1258

WIN1258, UTF8

Table 24.5. All Built-in Character Set Conversions

Conversion Name #ftn.id-1.6.11.5.8.4.2.4.1.1.1

Source Encoding

Destination Encoding

big5_to_euc_tw

BIG5

EUC_TW

big5_to_mic

BIG5

MULE_INTERNAL

big5_to_utf8

BIG5

UTF8

euc_cn_to_mic

EUC_CN

MULE_INTERNAL

euc_cn_to_utf8

EUC_CN

UTF8

euc_jp_to_mic

EUC_JP

MULE_INTERNAL

euc_jp_to_sjis

EUC_JP

SJIS

euc_jp_to_utf8

EUC_JP

UTF8

euc_kr_to_mic

EUC_KR

MULE_INTERNAL

euc_kr_to_utf8

EUC_KR

UTF8

euc_tw_to_big5

EUC_TW

BIG5

euc_tw_to_mic

EUC_TW

MULE_INTERNAL

euc_tw_to_utf8

EUC_TW

UTF8

gb18030_to_utf8

GB18030

UTF8

gbk_to_utf8

GBK

UTF8

iso_8859_10_to_utf8

LATIN6

UTF8

iso_8859_13_to_utf8

LATIN7

UTF8

iso_8859_14_to_utf8

LATIN8

UTF8

iso_8859_15_to_utf8

LATIN9

UTF8

iso_8859_16_to_utf8

LATIN10

UTF8

iso_8859_1_to_mic

LATIN1

MULE_INTERNAL

iso_8859_1_to_utf8

LATIN1

UTF8

iso_8859_2_to_mic

LATIN2

MULE_INTERNAL

iso_8859_2_to_utf8

LATIN2

UTF8

iso_8859_2_to_windows_1250

LATIN2

WIN1250

iso_8859_3_to_mic

LATIN3

MULE_INTERNAL

iso_8859_3_to_utf8

LATIN3

UTF8

iso_8859_4_to_mic

LATIN4

MULE_INTERNAL

iso_8859_4_to_utf8

LATIN4

UTF8

iso_8859_5_to_koi8_r

ISO_8859_5

KOI8R

iso_8859_5_to_mic

ISO_8859_5

MULE_INTERNAL

iso_8859_5_to_utf8

ISO_8859_5

UTF8

iso_8859_5_to_windows_1251

ISO_8859_5

WIN1251

iso_8859_5_to_windows_866

ISO_8859_5

WIN866

iso_8859_6_to_utf8

ISO_8859_6

UTF8

iso_8859_7_to_utf8

ISO_8859_7

UTF8

iso_8859_8_to_utf8

ISO_8859_8

UTF8

iso_8859_9_to_utf8

LATIN5

UTF8

johab_to_utf8

JOHAB

UTF8

koi8_r_to_iso_8859_5

KOI8R

ISO_8859_5

koi8_r_to_mic

KOI8R

MULE_INTERNAL

koi8_r_to_utf8

KOI8R

UTF8

koi8_r_to_windows_1251

KOI8R

WIN1251

koi8_r_to_windows_866

KOI8R

WIN866

koi8_u_to_utf8

KOI8U

UTF8

mic_to_big5

MULE_INTERNAL

BIG5

mic_to_euc_cn

MULE_INTERNAL

EUC_CN

mic_to_euc_jp

MULE_INTERNAL

EUC_JP

mic_to_euc_kr

MULE_INTERNAL

EUC_KR

mic_to_euc_tw

MULE_INTERNAL

EUC_TW

mic_to_iso_8859_1

MULE_INTERNAL

LATIN1

mic_to_iso_8859_2

MULE_INTERNAL

LATIN2

mic_to_iso_8859_3

MULE_INTERNAL

LATIN3

mic_to_iso_8859_4

MULE_INTERNAL

LATIN4

mic_to_iso_8859_5

MULE_INTERNAL

ISO_8859_5

mic_to_koi8_r

MULE_INTERNAL

KOI8R

mic_to_sjis

MULE_INTERNAL

SJIS

mic_to_windows_1250

MULE_INTERNAL

WIN1250

mic_to_windows_1251

MULE_INTERNAL

WIN1251

mic_to_windows_866

MULE_INTERNAL

WIN866

sjis_to_euc_jp

SJIS

EUC_JP

sjis_to_mic

SJIS

MULE_INTERNAL

sjis_to_utf8

SJIS

UTF8

windows_1258_to_utf8

WIN1258

UTF8

uhc_to_utf8

UHC

UTF8

utf8_to_big5

UTF8

BIG5

utf8_to_euc_cn

UTF8

EUC_CN

utf8_to_euc_jp

UTF8

EUC_JP

utf8_to_euc_kr

UTF8

EUC_KR

utf8_to_euc_tw

UTF8

EUC_TW

utf8_to_gb18030

UTF8

GB18030

utf8_to_gbk

UTF8

GBK

utf8_to_iso_8859_1

UTF8

LATIN1

utf8_to_iso_8859_10

UTF8

LATIN6

utf8_to_iso_8859_13

UTF8

LATIN7

utf8_to_iso_8859_14

UTF8

LATIN8

utf8_to_iso_8859_15

UTF8

LATIN9

utf8_to_iso_8859_16

UTF8

LATIN10

utf8_to_iso_8859_2

UTF8

LATIN2

utf8_to_iso_8859_3

UTF8

LATIN3

utf8_to_iso_8859_4

UTF8

LATIN4

utf8_to_iso_8859_5

UTF8

ISO_8859_5

utf8_to_iso_8859_6

UTF8

ISO_8859_6

utf8_to_iso_8859_7

UTF8

ISO_8859_7

utf8_to_iso_8859_8

UTF8

ISO_8859_8

utf8_to_iso_8859_9

UTF8

LATIN5

utf8_to_johab

UTF8

JOHAB

utf8_to_koi8_r

UTF8

KOI8R

utf8_to_koi8_u

UTF8

KOI8U

utf8_to_sjis

UTF8

SJIS

utf8_to_windows_1258

UTF8

WIN1258

utf8_to_uhc

UTF8

UHC

utf8_to_windows_1250

UTF8

WIN1250

utf8_to_windows_1251

UTF8

WIN1251

utf8_to_windows_1252

UTF8

WIN1252

utf8_to_windows_1253

UTF8

WIN1253

utf8_to_windows_1254

UTF8

WIN1254

utf8_to_windows_1255

UTF8

WIN1255

utf8_to_windows_1256

UTF8

WIN1256

utf8_to_windows_1257

UTF8

WIN1257

utf8_to_windows_866

UTF8

WIN866

utf8_to_windows_874

UTF8

WIN874

windows_1250_to_iso_8859_2

WIN1250

LATIN2

windows_1250_to_mic

WIN1250

MULE_INTERNAL

windows_1250_to_utf8

WIN1250

UTF8

windows_1251_to_iso_8859_5

WIN1251

ISO_8859_5

windows_1251_to_koi8_r

WIN1251

KOI8R

windows_1251_to_mic

WIN1251

MULE_INTERNAL

windows_1251_to_utf8

WIN1251

UTF8

windows_1251_to_windows_866

WIN1251

WIN866

windows_1252_to_utf8

WIN1252

UTF8

windows_1256_to_utf8

WIN1256

UTF8

windows_866_to_iso_8859_5

WIN866

ISO_8859_5

windows_866_to_koi8_r

WIN866

KOI8R

windows_866_to_mic

WIN866

MULE_INTERNAL

windows_866_to_utf8

WIN866

UTF8

windows_866_to_windows_1251

WIN866

WIN

windows_874_to_utf8

WIN874

UTF8

euc_jis_2004_to_utf8

EUC_JIS_2004

UTF8

utf8_to_euc_jis_2004

UTF8

EUC_JIS_2004

shift_jis_2004_to_utf8

SHIFT_JIS_2004

UTF8

utf8_to_shift_jis_2004

UTF8

SHIFT_JIS_2004

euc_jis_2004_to_shift_jis_2004

EUC_JIS_2004

SHIFT_JIS_2004

shift_jis_2004_to_euc_jis_2004

SHIFT_JIS_2004

EUC_JIS_2004

[id="a",role="bare"]#id-1.6.11.5.8.4.2.4.1.1.1 [id="a"] 转换名称遵循标准命名方案：源编码的正式名称（所有非字母数字字符替换为下划线），后跟 to ，后跟同样处理后的目标编码名称。因此，这些名称有时会与 Table 24.3 中所示的惯例编码名称不同。

#id-1.6.11.5.8.4.2.4.1.1.1 The conversion names follow a standard naming scheme: The official name of the source encoding with all non-alphanumeric characters replaced by underscores, followed by to, followed by the similarly processed destination encoding name. Therefore, these names sometimes deviate from the customary encoding names shown in Table 24.3.

24.3.5. Further Reading #

这些是开始了解各种编码系统的好资料。

These are good sources to start learning about various kinds of encoding systems.

CJKV Information Processing: Chinese, Japanese, Korean & Vietnamese Computing
- Contains detailed explanations of EUC_JP, EUC_CN, EUC_KR, EUC_TW.
https://www.unicode.org/
- The web site of the Unicode Consortium.
RFC 3629
- UTF-8 (8-bit UCS/Unicode Transformation Format) is defined here.