This is the classic rookie mistake. In an ORM (Object Relational Mapping), a developer writes a loop: "Get 100 users; for each user, get their posts." This results in 101 separate DB queries.
This is the traditional and most widely used type. Data is organized into tables with rows and columns, similar to a spreadsheet. This is the classic rookie mistake
If you are building a new application, ask these three questions: for each user
This was the revolution. Edgar F. Codd of IBM proposed the relational model. Data is stored in tables (spreadsheet-like structures) with rows (records) and columns (attributes). This is the classic rookie mistake
SQL Injection is still the OWASP Top 10 vulnerability. Never trust user input. Modern DBs offer: