Advantages and limitations of relational algebra

Advantages of relational algebra

The relational algebra has solid mathematical background. The mathematical background of relational algebra is the basis of many interesting developments and theorems. If we have two expressions for the same operation and if the expressions are proved to be equivalent, then a query optimizer can automatically substitute the more efficient form. Moreover, the relational algebra is a high level language which talks in terms of properties of sets of tuples and not in terms of for-loops.

Limitations of relational algebra

1. The relational algebra can’t do arithmetic.

For example, if we want to know the price of 101 of petrol, by assuming a 10% increase in the price of the petrol, which can’t be done using relational algebra.

2. The relational algebra cannot sort or print results in various formats.

For example we want to arrange the product name in the increasing order of their price. It can’t be done using relational algebra.

3. Relational algebra can’t perform aggregates.

4. The relational algebra cannot modify the database.

5. The relational algebra cannot compute “transitive closure”