mysql數據庫學習——2，數據庫的選定，創建，刪除和變更

mysql數據庫學習——2，數據庫的選定，創建，刪除和變更   數據庫選定，數據庫選定後依然可以使用其他數據庫中的數據表，只要指定【數據庫.數據表】即可

use db_name

select * from db_name.tbl_name

mysql> select schema_name from information_schema.schemata;
+--------------------+
| schema_name        |
+--------------------+
| information_schema |
| feng               |
| mysql              |
+--------------------+
3 rows in set (0.11 sec)

mysql> select table_name from information_schema.tables where table_schema='feng';
+------------+
| table_name |
+------------+
| feng       |
+------------+
1 row in set (0.05 sec)

create database db_name
create  database db_name if not exists db_name
create  database db_name if not exists db_name  character set utf8 collate utf8_icelandic_ci
show create database db_name\G

drop database db_name
drop database db_name if not exists db_name

alter database db_name default character set  utf8
                                          default collate  utf8_general_ci