I am very new to SQL and am in the process of building my first database. I have one data set that is 20,000 rows and 500 columns. This is quarterly financial data for multiple companies. The database will contain 10 of these tables (to start), it will grow to over 40. This leads to my question. Would it be best to load the all the data (20,000 rows X 500 columns) in one table for Q1 and the same for Q2, Q3 and Q4, respectively. Or should the data be divided into multiple tables to increase speed?
Lastly, is SQL server a secured environment or is it open where others can potentially access your code and or database?