实体框架 v4.1 喜欢 [英] Entity Framework v4.1 LIKE

问题描述

我必须如何构建我的查询以产生如下输出 SQL 查询:

How do I have to build my query to result in an output SQL query like:

SELECT
[viewRegisters].[Id] AS [IdRegister]
WHERE Name LIKE '%a%bc'

或

SELECT
[viewRegisters].[Id] AS [IdRegister]
WHERE Name LIKE 'a%b%c'

或

SELECT
[viewRegisters].[Id] AS [IdRegister]
WHERE Name LIKE 'a%b%c%'

我使用的是 .Net Framework 4.0、Entity Framework v4.1 和 C#.

I'm using .Net Framework 4.0, Entity Framework v4.1 and C#.

EF v4.1 转换了这种类型的 linq 查询:

EF v4.1 converts this type of linq queries from:

((IQueryable<T>)Data).Where(z => z.Field.Contains("a%b%c%"));

进入:

SELECT
[viewRegisters].[Id] AS [Id]
WHERE Name LIKE N'a~%b~%c~%' ESCAPE N'~'

那不是我想要的.我希望能够像直接在 DB 中那样使用百分比"符号.

That's not what I want. I want to be able to use the 'percent' symbol as I do directly in DB.

推荐答案

您必须使用 ESQL 如果您想要完整的通配符支持.Linq-to-entities 无法做到这一点，EFv4.1 代码首先(没有 EDMX)不支持模型定义函数，因此无法使用@Johann Blais 提供的解决方案.

You must use ESQL if you want full wildcard support. Linq-to-entities is not able to do that and EFv4.1 code first (without EDMX) doesn't have support for model defined functions so the solution provided by @Johann Blais cannot be used.

我猜运行 ESQL 查询的代码可能如下所示:

I guess the code to run ESQL query can look like:

string command = "SELECT VALUE e FROM ContextName.DbSetName AS e WHERE e.Field LIKE 'a%b%c%'"
ObjectContext ctx = ((IObjectContextAdapter)dbContext).ObjectContext;
ObjectQuery<EntityType> query = new ObjectQuery<EntityType>(command, ctx);
ObjectResult<EtntiyType> result = query.Execute(MergeOption.AppendOnly);

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