Normalization:

Database normalization is a design technique for structuring relational database tables.Highly normalized data reduces the data duplication. Redundant data is removed by the process of normalization.Normalization requires more tables and joins.

Denormalization:

De normalization is the process of attempting to optimize the performance of a data base by adding redundant data. Instead of joining several tables (Which affects the performance) to get a common information, just place some repeated values in the table is the use of de normalization

Surrogate Key

Surrogate key is a unique identifier. It is used to identify each row of a table uniquely. It also helps to track slowly changing dimensions. It replaces all natural keys. Surrogate keys are system generated keys, they are not derived from any data sources.