SQL injection is to do with SQL, a text based protocol for expressing commands to a server. Like all text based protocols trying to combine it with user-provided data immediately takes you into a world of peculiar escaping rules, magic quotes and constant security failures.

The fix for SQL injection is to work with binary APIs and protocols more. Parameterised queries are the smallest step to that world, where the user-supplied data rides alongside the query itself in separated length-checked buffers (well, assuming you're not writing buggy C - let's presume modern bounds checking languages here). They aren't combined back into text, instead the database engine itself knows how to combine them when it converts the SQL to its own internal binary in-memory representation, as IR objects.

Another fix is to move entirely to the world of type safe, bounds checked APIs via an ORM. But then you pay the cost of the impedance mismatch between the object and relational realms, which isn't great. I will provide a solution for this in part II.