在create table的语句中,key和index混淆在一起,官方手册中的解释是这样: KEY is normally a synonym for INDEX. The key attribute PRIMARY KEY can also be specified as just KEY when given in a column definition. This was implemented for compatibility with other database systems.
DB2 alter:add/delete/reset column 1.添加字段 alter table [table_name] add [column_name] [column_type] 2.更改字段类型 alter table [table_name] alter column [column_name] set data type [column_type] 注意: 更改字段类型是有限制的,如将字段改为比之前类型长度大的可以,如果要改小或者修改小数点长度,必须先drop掉原来