This article contains the SQL ALTER DATABASE syntax, as implemented by various database management systems (DBMSs). The syntax is listed exactly as each vendor has listed it on their website. Click on the applicable link to view more detail about the syntax for a particular vendor.

The DBMSs covered are MySQL, SQL Server, PostgreSQL, and Oracle Database.

MySQL

From the MySQL 5.7 Reference Manual:

ALTER {DATABASE | SCHEMA} [db_name]
    alter_specification ...
ALTER {DATABASE | SCHEMA} db_name
    UPGRADE DATA DIRECTORY NAME

alter_specification:
    [DEFAULT] CHARACTER SET [=] charset_name
  | [DEFAULT] COLLATE [=] collation_name

SQL Server

From the Transact-SQL Reference:

ALTER DATABASE { database_name  | CURRENT }
{
    MODIFY NAME = new_database_name 
  | COLLATE collation_name
  | <file_and_filegroup_options>
  | <set_database_options>
}
[;]

<file_and_filegroup_options >::=
  <add_or_modify_files>::=
  <filespec>::= 
  <add_or_modify_filegroups>::=
  <filegroup_updatability_option>::= 

<set_database_options>::=
  <optionspec>::= 
  <auto_option> ::= 
  <change_tracking_option> ::=
  <cursor_option> ::= 
  <database_mirroring_option> ::= 
  <date_correlation_optimization_option> ::=
  <db_encryption_option> ::=
  <db_state_option> ::=
  <db_update_option> ::=
  <db_user_access_option> ::=
  <external_access_option> ::=
  <FILESTREAM_options> ::=
  <HADR_options> ::=  
  <parameterization_option> ::=
  <recovery_option> ::= 
  <service_broker_option> ::=
  <snapshot_option> ::=
  <sql_option> ::= 
  <termination> ::=

PostgreSQL

From the PostgreSQL 9.5 Manual:

ALTER DATABASE name [ [ WITH ] option [ ... ] ]

where option can be:

    ALLOW_CONNECTIONS allowconn
    CONNECTION LIMIT connlimit
    IS_TEMPLATE istemplate

ALTER DATABASE name RENAME TO new_name

ALTER DATABASE name OWNER TO { new_owner | CURRENT_USER | SESSION_USER }

ALTER DATABASE name SET TABLESPACE new_tablespace

ALTER DATABASE name SET configuration_parameter { TO | = } { value | DEFAULT }
ALTER DATABASE name SET configuration_parameter FROM CURRENT
ALTER DATABASE name RESET configuration_parameter
ALTER DATABASE name RESET ALL

Oracle Database

From the Oracle Database Online Documentation 12c Release 1 (12.1):

ALTER DATABASE [ database ]
  { startup_clauses
  | recovery_clauses
  | database_file_clauses
  | logfile_clauses
  | controlfile_clauses
  | standby_database_clauses
  | default_settings_clauses
  | instance_clauses
  | security_clause
  } ;

The following outlines the detail of the various clauses.

startup_clauses::=

{ MOUNT [ { STANDBY | CLONE } DATABASE ]
| OPEN
  { [ READ WRITE ]
      [ RESETLOGS | NORESETLOGS ]
        [ UPGRADE | DOWNGRADE ]
  | READ ONLY
  }
}

recovery_clauses ::=

{ general_recovery
| managed_standby_recovery
| BEGIN BACKUP
| END BACKUP
}

general_recovery ::=

RECOVER
[ AUTOMATIC ]
[ FROM 'location' ]
{ { full_database_recovery
  | partial_database_recovery
  | LOGFILE 'filename'
  }
  [ { TEST
    | ALLOW integer CORRUPTION
    | parallel_clause
    }...
  ]
| CONTINUE [ DEFAULT ]
| CANCEL
}

full_database_recovery ::=

[ STANDBY ] DATABASE
[ { UNTIL { CANCEL
          | TIME date
          | CHANGE integer
          | CONSISTENT
          }
  | USING BACKUP CONTROLFILE
  | SNAPSHOT TIME date
  }...
]

partial_database_recovery::=

{ TABLESPACE tablespace [, tablespace ]...
| DATAFILE { 'filename' | filenumber }
             [, 'filename' | filenumber ]...
}

parallel_clause::=

{ NOPARALLEL | PARALLEL [ integer ] }

managed_standby_recovery::=

RECOVER
{ MANAGED STANDBY DATABASE
    [ { USING ARCHIVED LOGFILE
      | DISCONNECT [FROM SESSION]
      | NODELAY
      | UNTIL CHANGE integer
      | UNTIL CONSISTENT
      | parallel_clause
      }...
    | FINISH
    | CANCEL
    ]
| TO LOGICAL STANDBY { db_name | KEEP IDENTITY }
}

database_file_clauses ::=

{ RENAME FILE  'filename' [, 'filename' ]...
   TO 'filename'
| create_datafile_clause
| alter_datafile_clause
| alter_tempfile_clause
| move_datafile_clause
}

create_datafile_clause::=

CREATE DATAFILE
   { 'filename' | filenumber }
     [, 'filename' | filenumber ]...
   }
   [ AS { file_specification
          [, file_specification ]...
        | NEW
        }
   ]

alter_datafile_clause::=

DATAFILE
   { 'filename' | filenumber }
     [, 'filename' | filenumber ]...
   }
   { ONLINE
   | OFFLINE [ FOR DROP ]
   | RESIZE size_clause
   | autoextend_clause
   | END BACKUP
   }

 

alter_tempfile_clause::=

TEMPFILE
   { 'filename' [, 'filename' ]...
   | filenumber [, filenumber ]...
   }
   { RESIZE size_clause
   | autoextend_clause
   | DROP [ INCLUDING DATAFILES ]
   | ONLINE
   | OFFLINE
   }

move_datafile_clause::=

MOVE DATAFILE ( 'filename' | 'ASM_filename' | file_number )
 [ TO ( 'filename' | 'ASM_filename' ) ]
 [ REUSE ] [ KEEP ]

ASM_filename::=

{ fully_qualified_file_name
| numeric_file_name
| incomplete_file_name
| alias_file_name
}

autoextend_clause ::=

AUTOEXTEND
   { OFF
   | ON [ NEXT size_clause ]
        [ maxsize_clause ]
   }

maxsize_clause::=

MAXSIZE { UNLIMITED | size_clause }

logfile_clauses ::=

{ { ARCHIVELOG [ MANUAL ]
  | NOARCHIVELOG
  }
| [ NO ] FORCE LOGGING
| RENAME FILE 'filename' [, 'filename' ]...
    TO 'filename'
| CLEAR [ UNARCHIVED ]
    LOGFILE logfile_descriptor [, logfile_descriptor ]...
    [ UNRECOVERABLE DATAFILE ]
| add_logfile_clauses
| drop_logfile_clauses
| switch_logfile_clause
| supplemental_db_logging
}

add_logfile_clauses::=

ADD [ STANDBY ] LOGFILE
   { 
     { [ INSTANCE 'instance_name' ] | [ THREAD 'integer' ] }
     [ GROUP integer ] redo_log_file_spec
       [, [ GROUP integer ] redo_log_file_spec ]...
   | MEMBER 'filename' [ REUSE ] [, 'filename' [ REUSE ] ]...
        TO logfile_descriptor [, logfile_descriptor ]...
   }

drop_logfile_clauses::=

DROP [ STANDBY ] LOGFILE
   { logfile_descriptor
     [, logfile_descriptor ]...
   | MEMBER 'filename'
            [, 'filename' ]...
   }

switch_logfile_clause::=

SWITCH ALL LOGFILES TO BLOCKSIZE integer

supplemental_db_logging ::=

{ ADD | DROP } SUPPLEMENTAL LOG
{ DATA
| supplemental_id_key_clause
| supplemental_plsql_clause
}

supplemental_id_key_clause::=

DATA
( { ALL | PRIMARY KEY | UNIQUE | FOREIGN KEY }
    [, { ALL | PRIMARY KEY | UNIQUE | FOREIGN KEY } ]...
)
COLUMNS

supplemental_plsql_clause::=

DATA FOR PROCEDURAL REPLICATION

logfile_descriptor::=

{ GROUP integer
| ('filename' [, 'filename' ]...)
| 'filename'
}

controlfile_clauses ::=

CREATE { [ LOGICAL | PHYSICAL ] STANDBY | FAR SYNC INSTANCE }
  CONTROLFILE AS
  'filename' [ REUSE ]
| BACKUP CONTROLFILE TO
  { 'filename' [ REUSE ]
  | trace_file_clause
  }

standby_database_clauses ::=

{ { activate_standby_db_clause
| maximize_standby_db_clause
| register_logfile_clause
| commit_switchover_clause
| start_standby_clause
| stop_standby_clause
| convert_database_clause
} [ parallel_clause ] }
|
{ switchover_clause | failover_clause }

activate_standby_db_clause::=

ACTIVATE
     [ PHYSICAL | LOGICAL ]
     STANDBY DATABASE
     [ FINISH APPLY ]

maximize_standby_db_clause::=

SET STANDBY DATABASE TO MAXIMIZE
{ PROTECTION | AVAILABILITY | PERFORMANCE }

register_logfile_clause::=

REGISTER [ OR REPLACE ]
  [ PHYSICAL | LOGICAL ]
LOGFILE [ file_specification  [, file_specification ]...
  [ FOR logminer_session_name ]

switchover_clause::=

SWITCHOVER TO target_db_name [ VERIFY | FORCE ]

failover_clause::=

FAILOVER TO target_db_name [ FORCE ]

commit_switchover_clause::=

{ PREPARE | COMMIT } TO SWITCHOVER
[ TO { { [ PHYSICAL | LOGICAL ] PRIMARY
     | [ PHYSICAL ] STANDBY
     } [ { WITH | WITHOUT } SESSION SHUTDOWN
         { WAIT | NOWAIT }
       ]
     | LOGICAL STANDBY
     }
| CANCEL
]

start_standby_clause::=

START LOGICAL STANDBY APPLY
[ IMMEDIATE ]
[ NODELAY ]
[ NEW PRIMARY dblink
| INITIAL [ scn_value ]
| { SKIP FAILED TRANSACTION | FINISH }
]

stop_standby_clause::=

{ STOP | ABORT } LOGICAL STANDBY APPLY

convert_database_clause::=

CONVERT TO ( PHYSICAL | SNAPSHOT ) STANDBY

default_settings_clauses::=

{ DEFAULT EDITION = edition_name
| SET DEFAULT { BIGFILE | SMALLFILE } TABLESPACE
| DEFAULT TABLESPACE tablespace
| DEFAULT TEMPORARY TABLESPACE { tablespace | tablespace_group_name }
| RENAME GLOBAL_NAME TO database.domain [.domain ]...
| ENABLE BLOCK CHANGE TRACKING [ USING FILE 'filename' [ REUSE ] ]
| DISABLE BLOCK CHANGE TRACKING
| [NO] FORCE FULL DATABASE CACHING
| flashback_mode_clause
| set_time_zone_clause
}

set_time_zone_clause::=

SET TIME_ZONE =
   '{ { + | - } hh : mi | time_zone_region }'

flashback_mode_clause ::=

FLASHBACK { ON | OFF }

instance_clauses::=

{ ENABLE | DISABLE } INSTANCE 'instance_name'

security_clause ::=

GUARD { ALL | STANDBY | NONE }

Using the GUI

Most DBMSs allow you to alter databases using the GUI. This could be a GUI supplied with the product or one developed by a third party. For example,  MySQL Workbench is a GUI tool that can be used with MySQL.