In the previous chapter, we discussed basic Phoenix commands for CRUD operations. In this chapter we will be digging deep into working with tables (creating, altering, and dropping tables), Phoenix available clauses (LIMIT, WHERE, GROUP BY, HAVING, and ORDER BY), data constraints (NOT NULL) and conditional operators (AND, OR, IN, LIKE, and BETWEEN) for data retrieval.
4.1 Constraints
Constraints are rules applied on the values, structure or result set. You can enforce constraints on columns and tables, such as PRIMARY KEY, ...
