Add alter table

[wubx]

Summary

some time not think ok , there maybe design wrong column type or lose column

We need add alter table add column or remove column , change column.

[dantengsky]

@sundy-li is it reasonable/proper to introduce another filed, let say, column_id to DataField?

[sundy-li]

What does column_id mean? Is it something like table_id to identify unique column ?

[dantengsky]

What does column_id mean? Is it something like table_id to identify unique column ?

yes, all the columns are uniquely identified by column_id, and

• column_id never changes, if the column is renamed.
• column_id increased monotonically, if a new column was added.
• column_id will not be re-used, if a column is dropped

[dantengsky]

oh, forget to say,

columns are uniquely identified by column_id in the scope of a given table

columns of different tables, may have same column id

[dantengsky]

@sundy-li let me try to address this issue without touching the DataField