Relational Completeness
A query language is "relationally complete" if any R.A. query can be expressed in it.
- Does not mean all R.A. operations are available
- The concept is analogous, but not identical, to Turing-completeness
Commercial query languages are mostly much more powerful than the R.A.
- Aggregates, grouping, etc.
- We'll look later at relational calculus and QBE, which are also relationally complete