In-Memory SQL Engine
Also known as: In-Memory SQL Engine (Custom)
In-Memory SQL Engine You're building a tiny in-memory SQL system (no real database). All values are strings, and each table has a fixed column order. Implement class SQL with these methods: - createTable(tableName, columns): Create OR REPLACE a table (drop existing rows). - insertRow(tableName, values): Insert a row where values[i] corresponds to columns[i]. - deleteRows(tableName, whereColumn, whereValue): Delete ALL rows matching the filter. - selectRows(tableName, columns, whereColumn, whereValue): Return matching rows, projecting only the requested columns, in insertion order. run_sql_script below executes a list of commands against your SQL instance.
You're implementing CREATE, INSERT, SELECT, and DELETE from scratch—no shortcuts. Interviewers love it because it exposes whether you can follow a spec precisely without drifting. The trap is getting lost in state management halfway through. Keep your table representation explicit and the rest follows.
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