Oracle Pro*C in One Book — Legacy Maintenance and Migration

We take a monthly seller settlement batch for a virtual shopping mall from start to finish. Using Pro*C fundamentals, we read the source, fix four hidden defects with minimal patches, reduce database round trips from 265,893 to 359 through array processing, then port it to ECPG and JDBC and prove that all three outputs are identical, line for line. We run every command directly against Oracle Database Free and PostgreSQL in Docker.