MissingSchemaAction

MissingSchemaAction is an enumeration used by the Entity Framework to describe how to handle discrepancies between the conceptual model and the underlying store schema during initialization or schema discovery. It applies when an ObjectContext connects to a database and the store schema does not fully align with the model.

Typical values provide a choice of behavior for how to respond to missing or mismatched schema elements. Common options include Throw, Ignore, and Add. Throw signals that a mismatch should cause an exception to be raised. Ignore instructs the framework to proceed without reporting or addressing the missing elements. Add requests that the framework attempt to reconcile the situation by incorporating or adapting the missing schema elements. The exact semantics can vary between EF versions, but the general idea is to control whether and how missing schema items are treated during model-store alignment.

Usage often involves configuring a connection’s MissingSchemaAction before or during initialization, for example by setting the action on the ObjectContext or EntityConnection. This setting can affect runtime behavior and debugging, and it can have security and data-integrity implications if it leads to automatic schema modifications in a production environment.

Note that MissingSchemaAction is associated with older, ObjectContext-based versions of the Entity Framework. Modern EF workflows (such as those based on DbContext and migrations) use different mechanisms to handle schema mismatches, and EF Core does not include this exact enumeration.

See also: Entity Framework, ObjectContext, EntityConnection, schema mapping, migrations.