Server System Variables Note Setting  foreign_key_checks  to 1 does not trigger a scan of the existing table data. Therefore, rows added to the table while  foreign_key_checks = 0  are not verified for consistency. Dropping an index required by a foreign key constraint is not permitted, even with foreign_key_checks=0 . The foreign key constraint must be removed before dropping the index. • ft_boolean_syntax Command-Line Format --ft-boolean-syntax=name System Variable ft_boolean_syntax Scope Global Dynamic Yes SET_VAR  Hint Applies No Type String Default Value + -><()~*:""&| The list of operators supported by boolean full-text searches performed using  IN BOOLEAN MODE . See Section 12.10.2, “Boolean Full-Text Searches” . The default variable value is  ’+ -><()~*:""&|’ . The rules for changing the value are as follows: •Operator function is determined by position within the string. •The replacement value must be 14 characters. •Each character must be an ASCII nonalphanumeric character. •Either the first or second character must be a space. •No duplicates are permitted except the phrase quoting operators in positions 11 and 12. These two characters are not required to be the same, but they are the only two that may be. •Positions 10, 13, and 14 (which by default are set to  : ,  & , and  | ) are reserved for future extensions. • ft_max_word_len Command-Line Format --ft-max-word-len=# System Variable ft_max_word_len Scope Global Dynamic No SET_VAR  Hint Applies No Type Integer 801