3.13. Collations

Collations are objects which allow specifying the sorting mode and character classification behavior either per column or per operation. Collations can be used to override the way data is sorted in a database even if this one has its own mode defined by LC_COLLATE and LC_CTYPE attributes.

Attribute Description
Collation This field can be used to create a new object from an existing collation.
Locale This is a shortcut to specify the attributes LC_COLLATE and LC_CTYPE.
Encoding Charset in which the collation works.
Modifier Present in Basics, LC_COLLATE, and LC_LOCALE groups this field can be used to provide extra modifiers (like custom currency code) to a certain locale.
Provider The provider attribute specifies the provider to use for locale services associated with a collation, like libc or icu.
Deterministic Indicates that the collation is a deterministic one. A deterministic collation uses deterministic comparisons, which consider strings that are not byte-wise equal to be unequal even if they are considered logically equal by the comparison.
LC_COLLATE This group of fields is used to determine in which language the string sorting must be applied.
LC_CTYPE This group of fields is used to specify in which language the character categorization (upper, lower, and digit) must be applied.

Note: the attributes Collation, Locale, LC_COLLATE and LC_CTYPE are mutually exclusive, thus you can't use all of them at once.

Mar 9, 2021 at 16:59