emqx4.3/apps/emqx_data_bridge/etc/emqx_data_bridge.conf

##--------------------------------------------------------------------
## EMQ X Bridge Plugin
##--------------------------------------------------------------------

emqx_data_bridge.bridges: [
#    {name: "mysql-abc"
#     type: mysql
#     config: {
#        server: "127.0.0.1:3306"
#        database: mqtt
#        pool_size: 1
#        user: root
#        password: public
#        auto_reconnect: true
#        ssl: false
#     }
#    },
#    {name: "mysql-def"
#     type: mysql
#     config: {
#        server: "127.0.0.1:3306"
#        database: mqtt
#        pool_size: 1
#        user: root
#        password: public
#        auto_reconnect: true
#        ssl: false
#     }
#    }
]