MySQL中表的基本操作-1

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.00 sec)

mysql> create database justforfun;
Query OK, 1 row affected (0.08 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| justforfun         |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.00 sec)

mysql> drop database justforfun;
Query OK, 0 rows affected (0.33 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.00 sec)

mysql> show engines;
+--------------------+---------+--------------------------------------------------

----------+--------------+------+------------+
| Engine             | Support | Comment

| Transactions | XA   | Savepoints |
+--------------------+---------+--------------------------------------------------

----------+--------------+------+------------+
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables

| NO           | NO   | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema

| NO           | NO   | NO         |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and

foreign keys | YES          | YES  | YES        |
| CSV                | YES     | CSV storage engine

| NO           | NO   | NO         |
| MyISAM             | YES     | MyISAM storage engine

| NO           | NO   | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary

tables  | NO           | NO   | NO         |
+--------------------+---------+--------------------------------------------------

----------+--------------+------+------------+
6 rows in set (0.04 sec)

mysql> show engines \G
*************************** 1. row ***************************
Engine: MRG_MYISAM
Support: YES
Comment: Collection of identical MyISAM tables
Transactions: NO
XA: NO
Savepoints: NO
*************************** 2. row ***************************
Engine: PERFORMANCE_SCHEMA
Support: YES
Comment: Performance Schema
Transactions: NO
XA: NO
Savepoints: NO
*************************** 3. row ***************************
Engine: InnoDB
Support: DEFAULT
Comment: Supports transactions, row-level locking, and foreign keys
Transactions: YES
XA: YES
Savepoints: YES
*************************** 4. row ***************************
Engine: CSV
Support: YES
Comment: CSV storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 5. row ***************************
Engine: MyISAM
Support: YES
Comment: MyISAM storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 6. row ***************************
Engine: MEMORY
Support: YES
Comment: Hash based, stored in memory, useful for temporary tables
Transactions: NO
XA: NO
Savepoints: NO
6 rows in set (0.00 sec)

mysql> show variables like 'storage_engine';
+----------------+--------+
| Variable_name  | Value  |
+----------------+--------+
| storage_engine | InnoDB |
+----------------+--------+
1 row in set (0.00 sec)

mysql>