为什么实体框架为使用NUMERIC(19)定义的列传递参数DECIMAL(5,0)? [英] Why is Entity Framework passing a parameter as DECIMAL(5,0) for a column defined with NUMERIC(19)?

问题描述

在SQL Server中，数据库列定义为NUMERIC(19).在< edmx:StorageModels>中，edmx显示:

A database column is defined as NUMERIC(19) in SQL Server. In <edmx:StorageModels>, the edmx shows:

<Property Name="supplier_id" Type="numeric" Nullable="false" Precision="19" />

在< edmx:ConceptualModels>中，我将其视为:

In <edmx:ConceptualModels>, I see it as:

<Property Type="Decimal" Name="supplier_id" Nullable="false" Precision="19" Scale="0" />

在数据库中，带有WHERE子句中此列的SELECT带有以下参数定义:

In the database, a SELECT with this column in the WHERE clause comes through with this parameter definition:

(@p__linq__0 decimal(5,0))

此WHERE子句:

WHERE ([Extent1].[supplier_id] = @p__linq__0)

我知道数字和十进制是等效的，但是为什么精度会改变?

I understand that numeric and decimal are equivalent, but why is the precision getting changed?

推荐答案

(@p__linq__0 decimal(5,0))是您提供的参数值的精度.

(@p__linq__0 decimal(5,0)) is the Precision of the parameter value your provided.

例如，

decimal number = 12345m;
var result = context.MyTables.Where(x => x.Number == number).ToList();

然后查询将像这样-

exec sp_executesql N'SELECT 
    [Extent1].[Id] AS [Id], 
    [Extent1].[Number] AS [Number]
    FROM [dbo].[MyTable] AS [Extent1]
    WHERE [Extent1].[Number] = @p__linq__0',N'@p__linq__0 decimal(5,0)',
    @p__linq__0=12345

答案是 where子句的SQL语句不需要相同的精度编号.

The answer is SQL Statement doesn't need to be same Precision number for where clause.

实体框架足够聪明，可以找出数字的精度，并且仅创建具有所需精度的查询.

Entity Framework is smart enough to figure out the Precision of a number, and only creates the query with required Precision.

注意:插入和更新不是这种情况； EF创建的查询与列的精度相同.

Note: it is not the case for Insert and Update; EF creates a query with the same Precision as Column.

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