Oracle DB to EF not working correctly for NUMBER(2,0)

问题

I have a table column defined like this:

ENTRY_STATUS NUMBER(2, 0)

And in my EntityFramework class the respective field is defined like this:

[Column("ENTRY_STATUS")]
public int Status { get; set; }

When checking the value to get an entry it works perfectly fine:

var order = testDbContext.Orders.FirstOrDefault(o => o.Status > 1);

But when I check the order entity after this statement it is always zero:

if (order != null)
{
    if (order.Status == 3) //Always Zero!!!
    { //Do something... 
    }
}

What went wrong here with my definitions? How do I fix this?

回答1:

The Oracle Database Column for a .Net Int32 should be: NUMBER(9, 0)

As per the Conversion Table:

+------------------------------+------------------+-----------------+
|         Oracle Type          | Default EDM Type | Custom EDM Type |
+------------------------------+------------------+-----------------+
| Number(1,0)                  | Int16            | bool            |
| Number(2,0) to Number(3,0)   | Int16            | byte            |
| Number(4,0)                  | Int16            | Int16           |
| Number(5,0)                  | Int16            | Int32           |
| Number(6,0) to Number(9,0)   | Int32            | Int32           |
| Number(10,0)                 | Int32            | Int64           |
| Number(11,0) to Number(18,0) | Int64            | Int64           |
| Number(19,0)                 | Int64            | Decimal         |
+------------------------------+------------------+-----------------+

Edit:

I found a way you can force the Number(2,0) to be translated to a byte in the App.Config for Database-First approach:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <connectionStrings>
  </connectionStrings>
  <oracle.dataaccess.client>
    <settings>
      <add name="bool" value="edmmapping number(1,0)" />
      <add name="byte" value="edmmapping number(3,0)" />
      <add name="int16" value="edmmapping number(4,0)" />

REF: https://docs.oracle.com/database/121/ODPNT/entityDataTypeMapping.htm#ODPNT8300

回答2:

The query

var order = testDbContext.Orders.FirstOrDefault(o => o.Status > 1);

is executed on the server so it returns the excepted result.

Then the Order entity is created and EF tries to map a value of ENTRY_STATUS column from number(2,0) to Int32 which is not possible.

In my point of view the best solution is to change a type of Status to Int16

[Column("ENTRY_STATUS")]
public Int16 Status { get; set; }

回答3:

It was a caching problem.
Following article helped me: http://codethug.com/2016/02/19/Entity-Framework-Cache-Busting/

I don't know if it is an EF bug that the query itself (o => o.Status > 1) recognizes the change in the database but than retrieves the data from the cache, which can be different.
Anyway, adding AsNoTracking() solved the problem:

var order = testDbContext.Orders.AsNoTracking().FirstOrDefault(o => o.Status > 1);

来源：https://stackoverflow.com/questions/46589929/oracle-db-to-ef-not-working-correctly-for-number2-0

标签

Oracle

entity-framework