Entity framework: How to map Int64 field to Int32 db column?

Question

There is an int ID column in a MS SQL database table, but the entity class contains a long ID field, and I get the following message in the context:

"An exception occured while reading a database value. The expected type was 'System.Int64' but the actual value was of type 'System.Int32'."

I've already tried to set the column type:

modelBuilder.Entity<XXXEntity>()
            .Property(b => b.Id)
            .HasColumnName("XXXId")
            .HasColumnType("int");

but that does not work. What's the right solution?

I cannot change neither the entity class nor the db table.

force it to be int by using Convert.ToInt32(myLongIdField). But there is valid reason why the program doesn't allow you to insert long into int type column. use this only if you are very sure that your "long" data will not be too big. — Ppp
– Ppp, Commented May 17, 2017 at 8:49

Darjan Bogdan · Accepted Answer · 2017-05-17 08:43:34Z

2

You should map Int64 into bigint on SQL server:

 modelBuilder.Entity<XXXEntity>()
            .Property(b => b.Id)
            .HasColumnName("XXXId")
            .HasColumnType("bigint");

UPDATE: Since your SQL column data type is int, you should change your Id datatype inside XXXEntity class to Int32

edited May 17, 2017 at 8:43

answered May 17, 2017 at 8:15

Darjan Bogdan

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9 Comments

Aaaaaaaa Over a year ago

Thanks, but the same result.

Darjan Bogdan Over a year ago

@Aaaaaaaa what is the actual type of XXXId column on SQL Server?

Aaaaaaaa Over a year ago

int, as I wrote

Darjan Bogdan Over a year ago

@Aaaaaaaa then you should have two different Id properties. One for legacy db (e.g. LegacyId which corresponds to datatype inside legacy db) and one for new db (e.g. Id which corresponds to datatype of new db)

Aaaaaaaa Over a year ago

If there is no other solution, than I schould have two IDs, yes. Thanks!

|

Ppp · Accepted Answer · 2017-05-17 09:12:33Z

0

Not tested. But can try?

public long id { get { return id; } set { id.GetType() == typeof(Int64) ? id : Convert.ToInt64(id); }}

answered May 17, 2017 at 9:12

Ppp

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