Setting the Error Message Language. Adding a Collation to a Character Set. Collation Implementation Types. Choosing a Collation ID. Diagnostics During Index. Character Set Configuration. Error Messages and Common Problems. A simple character set requires only a configuration file, whereas a complex character set requires C source file that defines collation functions, multibyte functions, or both. You can use a copy of latin1. The syntax for the file is very simple:.
See Section For a complex character set, create a C source file that describes the character set properties and defines the support routines necessary to properly perform operations on the character set:. These correspond to the arrays for a simple character set. Swedish collations include Swedish rules. For example, in Swedish, the following relationship holds, which is not something expected by a German or French speaker:. It can make only one-to-one comparisons between characters.
See Section The result is a sequence of two collating elements, aaaa followed by bbbb. With UCA 5. For supplementary characters in UCA 4. The rule that all supplementary characters are equal to each other is nonoptimal but is not expected to cause trouble. These characters are very rare, so it is very rare that a multi-character string consists entirely of supplementary characters.
In Japan, since the supplementary characters are obscure Kanji ideographs, the typical user does not care what order they are in, anyway. If you really want rows sorted by the MySQL rule and secondarily by code point value, it is easy:. For supplementary characters based on UCA versions higher than 4. Some have explicit weights from the UCA allkeys. Others have weights calculated from this algorithm:. For example, the following chart shows two rare characters.
The first character is in the range E - FFFF , so it is greater than a surrogate but less than a supplementary. The second character is a supplementary. It is applicable to the UCS character repertoire. If the character set is ucs2 , comparison is byte-by-byte, but ucs2 strings should not contain surrogates, anyway. Character Sets and Collations in General. Specifying Character Sets and Collations. Collation Naming Conventions. Because the default collation for an instance of SQL Server is defined during setup, make sure that you specify the collation settings carefully when the following conditions are true: Your application code depends on the behavior of previous SQL Server collations.
You must store character data that reflects multiple languages. Important Altering the database-level collation doesn't affect column-level or expression-level collations. Note The code pages that a client uses are determined by the operating system OS settings.
Tip You can also try to use a different collation for the data on the server. Is this page helpful? Yes No. Any additional feedback? Skip Submit. Submit and view feedback for This product This page. View all page feedback. Distinguishes between uppercase and lowercase letters. If this option is selected, lowercase letters sort ahead of their uppercase versions.
If this option isn't selected, the collation is case-insensitive. That is, SQL Server considers the uppercase and lowercase versions of letters to be identical for sorting purposes. Distinguishes between accented and unaccented characters. If this option isn't selected, the collation is accent-insensitive. That is, SQL Server considers the accented and unaccented versions of letters to be identical for sorting purposes.
Distinguishes between the two types of Japanese kana characters: Hiragana and Katakana. If this option isn't selected, the collation is kana-insensitive. Omitting this option is the only method of specifying kana-insensitivity. Distinguishes between full-width and half-width characters. If this option isn't selected, SQL Server considers the full-width and half-width representation of the same character to be identical for sorting purposes.
Omitting this option is the only method of specifying width-insensitivity. A variation sequence consists of a base character plus an additional variation selector. That is, SQL Server considers characters built upon the same base character with differing variation selectors to be identical for sorting purposes.
For more information, see Unicode Ideographic Variation Database. Sorts and compares data in SQL Server tables based on the bit patterns defined for each character. Binary sort order is case-sensitive and accent-sensitive.
Binary is also the fastest sorting order. For more information, see the Binary collations section in this article. For non-Unicode data, Binary-code point uses comparisons that are identical to those for binary sorts. The advantage of using a Binary-code point sort order is that no data resorting is required in applications that compare sorted SQL Server data.
As a result, a Binary-code point sort order provides simpler application development and possible performance increases. If this option isn't selected, SQL Server uses the default non-Unicode encoding format for the applicable data types. Because Unicode data is used throughout the system, this scenario provides the best performance and protection from corruption of retrieved data. In this scenario, especially with connections between a server that's running a newer operating system and a client that's running an earlier version of SQL Server, or on an older operating system, there can be limitations or errors when you move data to a client computer.
Unicode data on the server tries to map to a corresponding code page on the non-Unicode client to convert the data. This isn't an ideal configuration for using multilingual data. You can't write Unicode data to the non-Unicode server. Problems are likely to occur when data is sent to servers that are outside the server's code page. Returns the character that corresponds to the specified Unicode code point value in the range 0—0x10FFFF.
If the specified value lies in the range 0—0xFFFF, one character is returned. For higher values, the corresponding surrogate is returned. Supplementary characters aren't supported for these wildcard operations. Other wildcard operators are supported. Describes how to set or change the collation of the instance of SQL Server. Note that changing the server collation does not change the collation of existing databases.
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