Set type

seekdb supports the SET type. SET is a string object that can have zero or more values, each of which must be one of the values in the list 'value1', 'value2', ...'.

SET is a variable-length type that supports the UTF8MB4 character set.

The syntax for SET is as follows:

SET('value1','value2',...) [CHARACTER SET charset_name] [COLLATE collation_name]

Internally, SET values are represented as integers. A SET column can have a maximum of 64 elements, each of which can be up to 255 characters long. The values of a SET column with multiple elements are separated by commas (,).

For example, a column defined as SET('a', 'b') NOT NULL can have the following values:

' '
'a'
'b'
'a,b'

The CHARACTER SET clause specifies the character set. You can use the COLLATE attribute and other attributes to specify the collation of the character set, if needed.

SET values are stored as numbers, with the least significant bit corresponding to the first element in the set. SET values are sorted numerically. NULL values are sorted before non-NULL values. If strict SQL mode is enabled, defining duplicate values generates a warning or error. When creating a table, trailing spaces are automatically removed from SET member values in the table definition.