Introduction

There are multiple types of databases, but the most common one is relational, and the language for managing relational databases is SQL. SQL is optimized for data persistence. However, executing business rules in it is inefficient. Therefore, before consumption, data is often fetched in application memory and transformed into objects. This transformation is called object-relational mapping.

There is a lot of complexity in mapping database records to objects. However, this complexity is mitigated by Object-Relational Mapper (ORM). Some ORMs only do mapping (called micro-ORMs), but many popular ORMs also abstract away database language and allow you to use the same language to execute business rules and process data:

Figure 6.1: How an ORM works in translating C# to SQL and back

The focus of this chapter will be on Entity Framework (EF)—the most popular ORM in .NET. In the practical sections of this chapter, you will use it to rapidly...