Mapping multiple tables into a single Entity in Entity Framework

Question

In in a website's database I am working on, I have two tables for example: Country & CountryLocale. The two tables contain the following columns:

Country: Id, Longitude, Latitude CountryLocale: Id, CountryId, CountryName, CultureId

What I want is:
- When I retrieve a Country, I want the Entity to contain: CountryId, CountryName, CultureId, Latitude & Longitude.
- When I create a new Country, to insert one record into Table Country and one to Table CountryLocale.
- When I create a new Country Locale, to create a record inside CountryLocale only

etc ...

Is this attainable? Thanks

Eranga · Accepted Answer · 2012-03-20 14:45:59Z

1

You can use entity splitting to partially achieve that. CountryLocale would use the PK of Country as its PK. You can not insert to CountryLocale without a Country. Essentially its a single entity split into multiple tables.

    modelBuilder.Entity<Country>()
        .Map(mc =>
        {
            mc.Properties(n => new
            {
                n.Id,
                n.Longitude,
                n.Latitude
            });
            mc.ToTable("Country");
        })
        .Map(mc =>
        {
            mc.Properties(n => new
            {
                n.CountryName,
                n.CultureId
            });
            mc.ToTable("CountryLocale");
        });

answered Mar 20, 2012 at 14:45

Eranga

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3 Comments

Bill Over a year ago

CountryId cannot be PK of CountryLocale, as I might have multiple CountryLocale records per Country. Where would the above code? More illustration please. Thanks

Bill Over a year ago

I am not using CodeFirst by the way. I have the Database already present and using Entity Framework.

Eranga Over a year ago

@bhaidar Then obviously you can not map the properties in to a single entity. You would have to use a one-to-many mapping.

maxlego · Accepted Answer · 2012-03-20 14:00:41Z

0

use discriminator (Table per Hierarchy)

modelBuilder.Entity<CountryBase>()
    .Map<Country>(c => c.Requires("Type").HasValue((int)CountryType.Country))
    .Map<CountryLocale>(c => c.Requires("Type").HasValue((int)CountryType.CountryLocale));

and you can define your sub-entities as you like

answered Mar 20, 2012 at 14:00

maxlego

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1 Comment

Bill Over a year ago

Can i have more illustration please? Thanks

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