之前研究docker和数据库的交互，越发对docker这个东西喜爱了。因为平常偶尔会用到各类数据库测试环境验证一些想法，需要进一步简化进入到这些环境的步骤。
比如我现在有三套docker容器数据库测试环境：
MySQL 5.7
MySQL 8.0
Oracle 19.3
使用docker ps查看具体信息：
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
219b2d4fc7c4 container-registry.oracle.com/mysql/community-server:5.7.33 "/entrypoint.sh mysq…" 24 hours ago Up 24 hours (healthy) 0.0.0.0:32773->3306/tcp, 0.0.0.0:32772->33060/tcp mysql57
c4b0fe102401 container-registry.oracle.com/mysql/community-server:8.0.27 "/entrypoint.sh mysq…" 24 hours ago Up 24 hours (healthy) 0.0.0.0:32771->3306/tcp, 0.0.0.0:32770->33060/tcp, 0.0.0.0:32769->33061/tcp mysql
576076210b7b container-registry.oracle.com/database/enterprise:19.3.0.0 "/bin/sh -c 'exec $O…" 25 hours ago Up 25 hours (healthy) testdb
虽然正常我就可以通过docker exec一条命令，进入对应容器环境的数据库SQL操作界面：
docker exec -it mysql mysql -uroot -p
docker exec -it mysql57 mysql -uroot -p
docker exec -it testdb sqlplus / as sysdba
但总是输入这个也怪麻烦的，懒惰的我就在OCI的opc用户下加几个alias的环境变量。
#alias name='value'
alias mysql='docker exec -it mysql mysql -uroot -p'
alias mysql57='docker exec -it mysql57 mysql -uroot -p'
alias sql='docker exec -it testdb sqlplus / as sysdba'
另外mysql默认有密码：第一次容器运行的mysql，首次登录的密码可以通过docker logs mysql-container-name 查看到，登入后也会强制你修改密码，个人测试环境没必要考虑安全，我就索性选择清除了mysql的密码：
ALTER USER 'root'@'localhost' IDENTIFIED BY '';
一切设置就绪，下次当再登录这个环境，就可以使用我们设置好的别名直接进入对应数据库的SQL操作命令行界面：
[opc@oci-001 ~]$ mysql
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2920
Server version: 8.0.27 MySQL Community Server - GPL
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> \q
Bye
[opc@oci-001 ~]$ mysql57
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2883
Server version: 5.7.33 MySQL Community Server (GPL)
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> \q
Bye
[opc@oci-001 ~]$ sql
SQL*Plus: Release 19.0.0.0.0 - Production on Fri Nov 12 15:55:52 2021
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> exit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
[opc@oci-001 ~]$
以后就算维护容器，或是搞坏了某个容器环境重新建立一个，只要名字还维持之前的，就不需要改啥配置。
这简直太方便了，忍不住也记录下。