Inserting data inside Database using Entity Framework

Question

I have a generic repository where I have a method to save data into database. Knowing that I'm changing an old system, I have faced with this situation:

When I have to save an Area, for example, I need to insert the Id of the field based on the last value inserted inside by database, but for some reason when I try to persist this, an error telling that I can't insert null values into the id of the table appears.

I tried to do this:

areaRepository.Save(new Area{AreaCode = 999, AreaName =  "teste"});
areaRepository.SaveAll();

The save method is:

public void Save(T obj)
{
    ctx.Set<T>().Add(obj);
}

And the save all method is

public void SaveAll()
{
    ctx.SaveChanges();
}

After executing the SaveAll method the error rises.

{"ORA-01400: is not possible to insert null in (\"CELG\".\"EPW_AREAS\".\"AREA_CODE\")\nORA-06512: at line 4"}

Knowing that I'm trying to force the AREA_CODE value, why entity framework doesn't add it and consider the value as null?

Is there a way to force it ?

Does anyone can help ?

Thanks in advice.

Update:

Entity class:

[Table("EPW_AREAS", Schema="CELG")]
public class Area
{
    [Key]
    [Column("AREA_CODE")]
    public int AreCode { get; set; }
    [Column("AREA_NAME")]
    public string AreName { get; set; }
}

Update 2

Context

    public WsContext(string sConnectionString)
        : base(sConnectionString)
    {
    }

    public DbSet<Area> Areas { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
    }

Update 3

CREATE TABLE CELG.EPW_AREAS
(
  AREA_CODE  NUMBER                            NOT NULL,
  AREA_NAME    VARCHAR2(30 BYTE)
)
TABLESPACE TBS_CELG_DATA
PCTUSED    0
PCTFREE    10
INITRANS   1
MAXTRANS   255
STORAGE    (
        INITIAL          64K
        NEXT             1M
        MINEXTENTS       1
        MAXEXTENTS       UNLIMITED
        PCTINCREASE      0
        BUFFER_POOL      DEFAULT
       )
LOGGING 
NOCOMPRESS 
NOCACHE
NOPARALLEL
MONITORING;

The most likely problem is that your mapping is wrong. If you want further help you will have to provide the mapping code. — Igor
– Igor, Commented Oct 11, 2017 at 20:24
are you sure that the column accepts null values and it is not a "not null" column? — Ioannis G.
– Ioannis G., Commented Oct 11, 2017 at 20:26

Isma · Accepted Answer · 2017-10-11 20:56:49Z

4

The error might occur because Entity Framework is ignoring the value you set for your AreaCode property because it is set up as the Key and by convention EF expects this key to be generated automatically by your DB system.

You can try to disable it as follows:

[Table("EPW_AREAS", Schema="CELG")]
public class Area
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    [Column("AREA_CODE")]
    public int AreCode { get; set; }
    [Column("AREA_NAME")]
    public string AreName { get; set; }
}

Make sure you don't try to add the same area code more than once though.

answered Oct 11, 2017 at 20:56

Isma

15.3k5 gold badges42 silver badges54 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Steve Greene Over a year ago

Beat me to it :)

ruynunes Over a year ago

Thanks man !!!!! I'm really a noob into entity framework and those easy things sometimes aren't so easy to discover !

Isma Over a year ago

No problem, we've all been there ;-)

Collectives™ on Stack Overflow

Inserting data inside Database using Entity Framework

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related