Re: How to make RDBMS ?

tony <tony_at_email.com> wrote in message news:3C1A41B5.2070104_at_email.com...
>
> I'm thinking to make RDBMS itself with C or C++ language.
> Before starting, I already got problems...
> SELECT * FROM table1;
> As you guys know, the statement above retrieve all records in the
> table1. It's easy to retrieve from memory, but if the table1 has
> 1,000,000 rows
> and 10 columns, what RDBMS should do with that huge table ?
> The RDBMS should put all records in the memory ? 1,000,000 rows & 10
> columns r fine, but if the table has 1,000,000,000 & 1,000 columns ?
> This is totally wasting memory space if the RDBMS put the all records
> in to memory.
>
> anybody knows how RDBMS treats those tables(files) ?

The rule of thumb is that everything is stored on disk unless it is an intermediate result and you are sure it fits comfortably in your memory.

• Jan Hidders