someone, please illuminate me

I had been a programmer of java, C++ and C, which, compared with netsuite script, belongs to a lower level. If you have experiences with those languages, you know that it works quite different from netsuite.

According to my personal understanding, netsuite is a platform, which is highly integrated. You do not have to spend too much time and energy to develop, since the platform provides many existing modules or APIs for you to invoke. But this causes a problem.

For example, in java, if you want to persist some records into the database, you need to know that which table does the fields belong to. After going through the developing guide of suite, I found that there are APIs similar to that. However, how do we identify the table we store the data. Is it the internal ids? But the fields within the forms or records, they also have internal ids. Besides, in java, we could join tables with SQL. So, if we want to make queries crossing multiple tables, how could we manage to do that.