782 Server System Variables The collation used by the default database. The server sets this variable whenever the default database changes. If there is no default database, the variable has the same value as  collation_server . As of MySQL 8.0.18, setting the session value of this system variable is no longer a restricted operation. Assigning a value to the session  character_set_database  and  collation_database  system variables is deprecated and assignments produce a warning. Expect the session variables to become read-only (and assignments to produce an error) in a future version of MySQL in which it remains possible to access the session variables to determine the database character set and collation for the default database. The global  character_set_database  and  collation_database  system variables are deprecated; expect them to be removed in a future version of MySQL. The server’s default collation. See Section 10.15, “Character Set Configuration” . Command-Line Format --completion-type=# System Variable completion_type Scope Global, Session Dynamic Yes SET_VAR  Hint Applies No Type Enumeration Default Value NO_CHAIN Valid Values NO_CHAIN CHAIN RELEASE 0 1 Command-Line Format --collation-server=name System Variable collation_server Scope Global, Session Dynamic Yes SET_VAR  Hint Applies No Type String Default Value utf8mb4_0900_ai_ci • collation_server • completion_type Footnote This option is dynamic, but should be set only by server. You should not set this variable manually.