django 項目中mysql 的編碼，數據庫遷移問題
以管理員的身份進入cmd
net start mysql
mysql -u root -p
沒有密碼直接回車，進入mysql可以創建數據庫，
如退出mysql 執行 \q：命令
創建數據庫 記得指定編碼 create database orm_1128 character set utf8; orm_1128是數據庫名字
修改數據庫的字符集mysql>use mydb
mysql>alter database mydb character set utf8;
如果報錯，
ERROR 1045 (28000): Access denied for user ‘root‘@‘localhost‘ (using password: YES)
是因為在mysql5.6版本以後，就需要輸入密碼了，
設置新密碼，123，下次再登錄的時候就要輸入密碼123，
mysql> set password for root@localhost = password(‘123‘);
Query OK, 0 rows affected, 1 warning (0.29 sec)
=====
查看數據庫 ，可以看到已經創建的表
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| bookmanage1 |
| bookmanage2 |
| db1 |
| db2 |
| gu_orm |
| myorm |
| mysql |
| performance_schema |
| s5orm |
| school |
| sys |
+--------------------+
12 rows in set (0.06 sec)
選擇自己要修改的編碼的 數據庫，然後可以執行 \s; 命令 看到表的數據庫的編碼等信息，進行修改
mysql> use gu_orm;
Database changed
mysql> \s
--------------
mysql Ver 14.14 Distrib 5.7.18, for Win64 (x86_64)
Connection id: 70
Current database: gu_orm
Current user: root@localhost
SSL: Not in use
Using delimiter: ;
Server version: 5.7.18 MySQL Community Server (GPL)
Protocol version: 10
Connection: localhost via TCP/IP
Server characterset: latin1
Db characterset: latin1
Client characterset: gbk--------------------------------------------------------------
Conn. characterset: gbk-----------------------------------------------------------------------
TCP port: 3306
Uptime: 14 hours 39 min 56 sec
Threads: 4 Questions: 860 Slow queries: 0 Opens: 365 Flush tables: 1 Open tables: 256 Queries per second avg: 0.016
--------------
mysql> set character_set_client=utf8;------修改編碼
Query OK, 0 rows affected (0.05 sec)
創建表後如果出錯---
File "C:\Python36\lib\site-packages\django\db\backends\mysql\base.py", line 30, in <module>
‘Did you install mysqlclient or MySQL-python?‘ % e
django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: No module named ‘MyS
QLdb‘.
Did you install mysqlclient or MySQL-python?
C:\Users\lenovo\PycharmProjects\gu_ORM_11month>
沒有mysqldb（驅動）？？？
在python2之前的版本中是MySQLdb支持，到python3以後都用pymsql,
只需要調一下，在項目的下的__init__.py文件中 導入 import pymsql
寫上 pymysql.install_as-MySQLdb() ,就行，
在創建一對多的表的時候，記得把主表，一 的表放在 多 的表前面，要不生成數據庫時會報錯
執行python manage.py makemigrations
python manage.py migrate
創建好數據庫以後，可以在cmd裏看下數據庫，
use 數據庫名字 ，進入數據庫， \s 命令查看數據庫信息
show tables； 查看表
mysql> use gu_ORM Database changed mysql> show table -> ; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘‘ at line 1 mysql> show tables; +----------------------------+ | Tables_in_gu_orm | +----------------------------+ | auth_group | | auth_group_permissions | | auth_permission | | auth_user | | auth_user_groups | | auth_user_user_permissions | | django_admin_log | | django_content_type | | django_migrations | | django_session | | gu_orm_book | | gu_orm_publish | +----------------------------+ 12 rows in set (0.00 sec)
看到這裏，就說明已經與數據庫連接上了，與pycharm裏的表一樣
但每次都在cmd查數據不方便，就可以在pycharm裏設置，
表就會出現，apply ，OK ，可以使用了
一對多的表，先對一 的表插入數據，然後在多的表才能插入數據，因為先對多的表插入數據時，有一個外鍵，需要數據，所以先對一 的表插入數據，
關於數據庫的編碼問題
show create table 數據庫的表名； 查看 表的編碼
alter table 數據庫的表名 charset utf8； 修改表的編碼
-------
重新遷移數據庫時會發生的錯誤，
C:\Users\lenovo\PycharmProjects\gu_ORM_11month>python manage.py makemigrations No changes detected
記得在後面加上app名字
C:\Users\lenovo\PycharmProjects\gu_ORM_11month>python manage.py makemigrations gu_orm Migrations for ‘gu_orm‘: gu_orm\migrations\0001_initial.py - Create model Book - Create model Publish - Add field pu
blish to book
在執行python manage.py migrate
C:\Users\lenovo\PycharmProjects\gu_ORM_11month>python manage.py migrate Operations to perform: Apply all migrations: admin, auth, contenttypes, gu_orm, sessions Running migrations: Applying contenttypes.0001_initial... OK Applying auth.0001_initial... OK Applying admin.0001_initial... OK Applying admin.0002_logentry_remove_auto_add... OK Applying contenttypes.0002_remove_content_type_name... OK Applying auth.0002_alter_permission_name_max_length... OK Applying auth.0003_alter_user_email_max_length... OK Applying auth.0004_alter_user_username_opts... OK Applying auth.0005_alter_user_last_login_null... OK Applying auth.0006_require_contenttypes_0002... OK Applying auth.0007_alter_validators_add_error_messages... OK Applying auth.0008_alter_user_username_max_length... OK Applying gu_orm.0001_initial... OK Applying sessions.0001_initial... OK
django 項目中mysql 的編碼，數據庫遷移問題