DB2 is so hard to use, also its documentation... Even such a simple operation, it takes me much time...
Generally, char->varchar, smallint->integer, you can just modify the column through this sql:
alter table [table name] alter column [column name] set data type [new type]
But, if new column type is not compatible with existing column type, you need to modify it as follows:
1. maybe need to export old column data
2. drop the column: alter table [table name] drop column [column name]
3. add new column: alter table [table name] add column [column name] [column type]
4. reorg table [table name]
5. maybe need to import original data
相关资源：敏捷开发V1.0.pptx
