Are you wrestling with undesirable database columns once utilizing Entity Model four.1 Codification Archetypal? It’s a communal script: your people mightiness incorporate properties you don’t privation continued to the database. Possibly it’s a calculated tract, a impermanent adaptable, oregon information derived from another properties. Happily, Entity Model affords elegant options for ignoring circumstantial people properties throughout database mapping. This permits for cleaner database plan and prevents pointless information retention. Fto’s research however to accomplish this, streamlining your Codification Archetypal improvement.
Utilizing the [NotMapped] Property
The easiest and about nonstop attack to excluding a place from database persistence is by utilizing the [NotMapped] property. This property, portion of the Scheme.ComponentModel.DataAnnotations.Schema namespace, intelligibly indicators to Entity Model that a peculiar place ought to beryllium ignored throughout schema procreation. It’s a cleanable and readable manner to negociate your mappings.
For case, see a Merchandise people with a FullDescription place derived from another properties. By adorning FullDescription with [NotMapped], you guarantee it stays a calculated place inside your exertion logic with out creating a corresponding database file. This retains your database schema tidy and centered connected indispensable information.
Illustration:
national people Merchandise { national int Id { acquire; fit; } national drawstring Sanction { acquire; fit; } national drawstring ShortDescription { acquire; fit; } [NotMapped] national drawstring FullDescription { acquire { instrument $"{Sanction} - {ShortDescription}"; } } }Leveraging the DbModelBuilder.Disregard() Methodology
For much analyzable situations oregon once running with properties that can’t beryllium straight attributed, the DbModelBuilder.Disregard() technique supplies a almighty alternate. This technique, disposable inside the OnModelCreating methodology of your DbContext people, presents granular power complete the mapping procedure.
This attack is peculiarly utile once dealing with 3rd-organization courses oregon bequest codification wherever you mightiness not person nonstop entree to modify the people explanation. It permits you to keep a cleanable separation betwixt your information persistence logic and your area exemplary.
Illustration:
protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<product>().Disregard(p => p.FullDescription); } </product>Fluent API Configurations for Ignoring Properties
Entity Model’s Fluent API supplies a strong and kind-harmless mechanics for configuring your entity mappings. Piece frequently utilized for much analyzable relationships and configurations, it besides gives a manner to disregard properties. This methodology gives most flexibility and power, peculiarly generous successful situations with analyzable inheritance hierarchies oregon customized mapping necessities. It’s peculiarly favored by builders who like a codification-archetypal attack to configuration.
Illustration:
protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<product>() .Place(p => p.FullDescription) .IsIgnored(); } </product>Selecting the Correct Attack
Choosing the optimum methodology relies upon connected your circumstantial wants. The [NotMapped] property is mostly most well-liked for its simplicity and readability once you person nonstop entree to the people explanation. The DbModelBuilder.Disregard() and Fluent API approaches are much appropriate for analyzable eventualities, bequest codification, oregon conditions requiring centralized configuration. All attack offers the flexibility wanted to keep a cleanable and businesslike database schema.
- Usage
[NotMapped]for elemental instances. - Take
DbModelBuilder.Disregard()oregon Fluent API for analyzable situations oregon centralized configuration.
By knowing and making use of these strategies, you tin guarantee your Entity Model fashions precisely indicate your database schema, stopping pointless columns and optimizing database show. Effectual place exclusion leads to a cleaner, much maintainable information bed and streamlines your improvement workflow.
Infographic Placeholder: Ocular examination of the 3 strategies.
Applicable Examples and Usage Instances
See an e-commerce exertion wherever merchandise costs are calculated based mostly connected assorted elements. Storing the calculated terms successful the database would beryllium redundant and possibly pb to information inconsistencies. Ignoring the calculated terms place ensures the database stays the azygous origin of fact for basal costs, piece calculations are dealt with inside the exertion logic.
Different script entails person profiles with impermanent information, specified arsenic conference tokens oregon buying cart contents. These transient values ought to not beryllium persevered to the database, and using the strategies mentioned supra efficaciously manages their exclusion.
- Place the place to beryllium ignored.
- Take the due methodology (
[NotMapped],DbModelBuilder.Disregard(), oregon Fluent API). - Instrumentality the chosen technique successful your codification.
- Trial completely to guarantee the place is not persevered to the database.
Additional speechmaking: Entity Model Mapping Usher, Codification Archetypal Improvement, Information Annotations successful C.
FAQ
Q: Tin I usage these strategies for analyzable varieties?
A: Sure, you tin use these strategies to properties of analyzable varieties inside your entity exemplary.
Optimizing your Entity Model fashions with appropriate place direction is important for gathering businesslike and maintainable functions. By mastering the strategies outlined presentโutilizing the [NotMapped] property, the DbModelBuilder.Disregard() methodology, oregon the Fluent APIโyou addition exact power complete your database schema, stopping pointless information retention and enhancing exertion show. Return vantage of these instruments to streamline your improvement procedure and make a much sturdy information bed. Research our precocious usher to delve deeper into Entity Model optimization methods. See additional investigation connected subjects similar Codification Archetypal Migrations and precocious information annotation utilization to heighten your Entity Model skillset.
- Codification Archetypal Conventions
- POCO Entities
- DbContext People
- Information Persistence
- Entity-Relational Mapping (ORM)
- Database Schema
- Exemplary Configuration
Question & Answer :
My knowing is that the [NotMapped] property is not disposable till EF 5 which is presently successful CTP truthful we can not usage it successful exhibition.
However tin I grade properties successful EF four.1 to beryllium ignored?
Replace: I observed thing other unusual. I bought the [NotMapped] property to activity however for any ground, EF four.1 inactive creates a file named Disposed successful the database equal although the national bool Disposed { acquire; backstage fit; } is marked with [NotMapped]. The people implements IDisposeable of class however I don’t seat however that ought to substance. Immoderate ideas?
You tin usage the NotMapped property information annotation to instruct Codification-Archetypal to exclude a peculiar place
national people Buyer { national int CustomerID { fit; acquire; } national drawstring FirstName { fit; acquire; } national drawstring LastName{ fit; acquire; } [NotMapped] national int Property { fit; acquire; } }
[NotMapped] property is included successful the Scheme.ComponentModel.DataAnnotations namespace.
You tin alternatively bash this with Fluent API overriding OnModelCreating relation successful your DBContext people:
protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Buyer>().Disregard(t => t.LastName); basal.OnModelCreating(modelBuilder); }
http://msdn.microsoft.com/en-america/room/hh295847(v=vs.103).aspx
The interpretation I checked is EF four.three, which is the newest unchangeable interpretation disposable once you usage NuGet.
Edit : SEP 2017
Asp.Nett Center(2.zero)
Information annotation
If you are utilizing asp.nett center (2.zero astatine the clip of this penning), The [NotMapped] property tin beryllium utilized connected the place flat.
national people Buyer { national int Id { fit; acquire; } national drawstring FirstName { fit; acquire; } national drawstring LastName { fit; acquire; } [NotMapped] national int FullName { fit; acquire; } }
Fluent API
national people SchoolContext : DbContext { national SchoolContext(DbContextOptions<SchoolContext> choices) : basal(choices) { } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Buyer>().Disregard(t => t.FullName); basal.OnModelCreating(modelBuilder); } national DbSet<Buyer> Clients { acquire; fit; } }
