mysql create and delete databases, tables, modify the structure of tables

1. Create data
create database 数据库名;
2. Delete database
drop 数据库名;
3. Use database
use 数据库名;
4. Create table
create table 表名(
table structure...
);
5. Delete table
drop table 表名;

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The following content is copied from https://blog.csdn.net/qq_31209383/article/details/72820555

1. Add new fields to the table

   alter table table_name add column_name varchar2(20) not null

2. Delete a field in the table

   delete table table_name column column_name

3. Modify a field name in the table

   alter table table_name rename column oldname to newname

4. Add primary key constraint
   alter table table name
   add constraint constraint name primary key (column name)

5. Add unique constraint
   alter table table name
   add constraint constraint name unique (column name)

6. Add default constraint
   alter table table name
   add constraint constraint name default (content) for column name

7. Add check constraint
   alter table table name
   add constraint constraint name check (content)

8. Add foreign key constraint
   alter table table name
   add constraint constraint name foreign key (column name) references another table name (column name)

9. Delete constraint
   alter table table name
   drop constraint constraint name