Final answer:
0, 1, and M specifications are used in database design to represent different types of relationships between entities.
Step-by-step explanation:
In database design, the 0, 1, and M specifications refer to relationships between entities. These specifications help define how many instances of one entity can be associated with another entity in the database.
1. The 0 specification represents an optional relationship. It means that an instance of one entity can be associated with zero or more instances of another entity.
2. The 1 specification represents a mandatory relationship. It means that an instance of one entity must be associated with exactly one instance of another entity.
3. The M specification represents a many-to-many relationship. It means that an instance of one entity can be associated with multiple instances of another entity, and vice versa.