How to detect whether the mnesia schema and table have been created in code?

Question

I want to create an mnesia schema and table in my code after the system starts, so I need to detect weather the mnesia schema and table have been created. If not, I want to create them. Is this a good idea? And how can I detect the mnesia schema and table?

Answer 1

One way to handle this is -

1. Try creating table using mnesia:create_table(Table_name, ...)

2. If the table already exists (1) would return {aborted, {already_exists, Table_name}}

3. If table doesn't exit, it will be created and {atomic,ok} will be returned if successful

4. If there is any error in table creation in (3), {aborted, Reason} will be returned.

Handle each of these return values as required.

Answer 2

check out mnesia:system_info/1, mnesia:schema/0, mnesia:schema/1 and mnesia:table_info/2.