The document provides an overview of Query-by-Example (QBE) and Datalog, two relational query languages. QBE allows graphical queries to be expressed "by example" using relation templates. It supports queries on single and multiple relations, negation, conditions, ordering results, and aggregate functions. Datalog is a logic-based query language based on rules that define views. It allows recursion and negation. Key features include safety and the power of recursive queries.