全文+实体框架空间搜索4 [英] Full text + spatial search with Entity Framework 4

问题描述

假设我有一个名为Restaurants的表的SQL 2005数据库。餐厅表格包含以下列：

• RestaurantId


• 名称


• 纬度


• 经度

我想让用户按名称搜索餐馆和/或地址。如何编写LINQ查询来支持？我需要能够支持用户不输入名称或地址的可能性，只需输入名称，地址，名称和地址。

我的初始想法是写一个存储过程来计算两个lat / long对之间的距离和一个用于调用FREETEXTTABLE的表值函数，并在我的查询上使用一些条件加入调用。但是，似乎实体框架4不支持表值函数。

解决方案

您不能写任何 LINQ 在这个时间点支持地理空间查询 - 不管是$ code> EF 还是 LinqToSql 。这是因为没有可以处理SQL Server中存在的特殊 ST< any> 空间语法的 LINQ 语法（例如 STIntersects（..））

您将需要编写存储过程，然后您可以通过 EF 获得访问。

如果您希望返回 Sql GEOGRAPHY 字段在结果中，您将需要返回一个 VARBINARY（MAX）我认为是等效字段类型为 C＃代码。

希望帮助。

Let's say I have a SQL 2005 database with a table called Restaurants. The Restaurants table has the following columns:

• RestaurantId
• Name
• Latitude
• Longitude

I want to let users search for restaurants by name and/or address. How do I write the LINQ query to support this? I need to be able to support the possibility that the user doesn't enter in a name or address, just the name, just the address, or both name and address.

My initial idea was to write a stored procedure to calculate the distance between two lat/long pairs and a table value function for calling FREETEXTTABLE and using some conditional Join calls on my query. However, it appears that Entity Framework 4 doesn't support table value functions.

解决方案

You cannot write any LINQ that supports geospatial queries at this point of time - be it EF or LinqToSql. This is because there is no LINQ syntax which can handle the special ST<whatever> spatial syntax that exists in SQL Server 2008. (eg. STIntersects(..))

You will need to write a Stored Procedure which you can then get access to via EF.

If you wish to return a Sql GEOGRAPHY field in a result, you will need to return a VARBINARY(MAX) i think as the equivalent field type for the C# code.

Hope This Helps.

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