Probably you shouldn’t 🙂 The second most obvious answer is you should use it if your data isn’t relational. This usually manifests itself in having no easy way to describe your data as a set of columns. A good example is a database where you actually store paper documents, e.g. by scanning office mail. The … Read more
You have it backwards. The relationships in an E-R model are explicitly defined, while they are implicit in a relational model. No. Each Relational Model (RM) database base table and query result represents an application relationship. Entity-Relationship Modeling (E-RM) schemas are just a way of organizing (but under-using and under-specifying) (but with misunderstanding) relational tables … Read more
I follow a few rules: Primary keys should be as small as necessary. Prefer a numeric type because numeric types are stored in a much more compact format than character formats. This is because most primary keys will be foreign keys in another table as well as used in multiple indexes. The smaller your key, … Read more
Normalization is basically to design a database schema such that duplicate and redundant data is avoided. If the same information is repeated in multiple places in the database, there is the risk that it is updated in one place but not the other, leading to data corruption. There is a number of normalization levels from … Read more