entity framework number类型 oracle,c# – Oracle CHAR数据类型不适用于Entity Framework
我有一个问题是使用WHERE子句从Oracle数据库返回数据,该子句以CHAR列为目标.
我已经提供了以下步骤,这些步骤应该允许重新创建问题：
数据库设置
运行以下SQL以创建数据库表并插入模拟数据：
创建表订单(ORDER_NUMBER CHAR(10 BYTE));
插入订单价值(‘123456’);
从ORDERS中选择REPLACE(ORDER_NUMBER,”,’#’)作为ORDER_NUMBER
ORDER_NUMBER 123456 ####
正如您所看到的,存储在表中的值将填充为10个字符的空格(替换为“#”以使其显而易见).
实体框架设置
public class Order
{
public string OrderNumber { get; set; }
}
public class OrderMap : EntityTypeConfiguration
{
public OrderMap()
{
// Primary Key
HasKey(t => t.OrderNumber);
Property(t => t.OrderNumber)
.HasColumnName("ORDER_NUMBER")
.IsRequired()
.IsFixedLength()
.HasMaxLength(10)
.HasColumnType("CHAR")
.IsUnicode(false);
}
}
public class OrdersContext()
{
static OrdersContext()
{
Database.SetInitializer(null);
}
public DbSet Orders { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Configurations.Add(new OrderMap());
}
}
问题
class Program
{
static void Main(string[] args)
{
using (var context = new OrdersContext())
{
var order1 = context.Orders
.FirstOrDefault(o => o.OrderNumber == "123456");
// This works, the record is found in the database and I did not have to pad the filter sting to 10 characters
Debug.WriteLine("OrderNumber:" + order1.WorksOrder);
var orderFilter = "123456";
var order2 = context.Orders
.FirstOrDefault(o => o.WorksOrder == orderFilter);
// This fails. Using a variable to specify the filter does not work. No record is found.
Debug.WriteLine("OrderNumber:" + order2.WorksOrder);
}
}
}
所以,问题是当我想使用变量(orderFilter)时,该语句不会返回记录.我可以通过填充orderFilter来完成这项工作,如下所示,但我不认为我应该这样做：
var orderFilter = "123456".PadRight(10);
var order2 = context.Orders.FirstOrDefault(o => o.WorksOrder == orderFilter);
// This now works
Debug.WriteLine("OrderNumber:" + order2.WorksOrder);
通过使用绑定变量生成的SQL看起来不会在绑定变量上设置正确的数据类型.如果我启用跟踪,我们会看到以下SQL：
Opened connection at 22/04/2015 12:15:12 +01:00
SELECT “Extent1″.”ORDER_NUMBER” AS “ORDER_NUMBER”, FROM “ORDERS”
“Extent1” WHERE (“Extent1″.”ORDER_NUMBER” = :p__linq__0) AND (ROWNUM
<= (1) )
— p__linq__0: ‘123456 ‘ (Type = Object)
— Executing at 22/04/2015 12:15:12 +01:00
— Completed in 13 ms with result: OracleDataReader
我也尝试过使用DbFunctions.AsNonUnicode(orderFilter),但这看起来效果不大.
谁能解释一下这里发生了什么？如何在不填充过滤器或修剪列数据的情况下过滤CHAR数据类型？
注意
我无法更改数据库中列的数据类型.
此问题记录在几个地方,但没有明确的答案：
版本所有东西的数字：
>实体框架6.1.3
> .Net Framework 4.5.1
> Oracle.ManagedDataAccess 4.121.2.0 ODAC 12c版本3
> Oracle.ManagedDataAccess.EntityFramework 6.121.2.0
> Oracle数据库是11.2.0.3.0