It is recommended to include properties in the model that map to foreign keys in the database.
You may also choose to have one-way navigation, in which case you define the navigation property on only one of the types that participates in the relationship and not on both. Navigation properties allow you to navigate and manage relationships in both directions, returning either a reference object (if the multiplicity is either one or zero-or-one) or a collection (if the multiplicity is many). Every object can have a navigation property for every relationship in which it participates. Navigation properties provide a way to navigate an association between two entity types. The relationship may be governed by a referential constraint, which describes which end in the relationship is a principal role and which is a dependent role. Each relationship contains two ends that describe the entity type and the multiplicity of the type (one, zero-or-one, or many) for the two entities in that relationship. In Entity Framework, an entity can be related to other entities through an association or relationship. The Course table is the dependent table because it contains the DepartmentID column that links it to the Department table. The following image shows two tables that participate in one-to-many relationship. In a one-to-one relationship, the primary key acts additionally as a foreign key and there is no separate foreign key column for either table. The many-to-many relationship involves defining a third table (called a junction or join table), whose primary key is composed of the foreign keys from both related tables. In a one-to-many relationship, the foreign key is defined on the table that represents the many end of the relationship. There are generally three types of relationships: one-to-one, one-to-many, and many-to-many. A foreign key (FK) is a column or combination of columns that is used to establish and enforce a link between the data in two tables. In relational databases, relationships (also called associations) between tables are defined through foreign keys.
#Sqlite foreign key examples how to
It also gives some guidance on how to map and manipulate relationships. This article gives an overview of how Entity Framework manages relationships between entities.
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