[rusebor]

a view would allow you to change a field's type.

something like this

CREATE VIEW table_read_api AS SELECT TO_CHAR(now_int) as was_char FROM the_table;

not sure that the view is an internal structure because it will be exposed via API as it is.

SQL allows to swap the database at least if no specific SQL features are used.

[mk89]

> a view would allow you to change a field's type.

Which proves my point: if I change a field type ( in the table ), I will have to change the view type. I need to change 2 services because one of them changed an implementation detail.

[rusebor]

before the change

CREATE TABLE the_table (was_char CHAR);

CREATE VIEW table_read_api AS SELECT was_char FROM the_table;

a client consumes data via:

select was_char from table_read_api;

after the change

alter table the_table modify was_char int;

alter table the_table rename column was_char to now_int;

CREATE VIEW table_read_api AS SELECT TO_CHAR(now_int) as was_char FROM the_table;

the client uses the same query

select was_char from table_read_api;

the type of the column has not changed

it is still a char

only "internal implementation" is changed