向表添加索引 [英] Adding index to a table

问题描述

我有一个表 Person ： id，name

我经常有这样的疑问：

  select * from Person where name Like％abc％。 
  

我有两个问题：

1. 如何使用代码优先5（CTP5）实现此查询


2. 如何在名称列中添加索引，以便根据名称更快地进行数据检索在查询中？

解决方案

像运算符可以使用Contains函数执行：

  var query = from p in context.Persons 
其中p.Name.Contains（abc）
 select p ; 
  

索引必须由SQL添加 - EF中没有特殊的结构来创建索引。您可以从DB初始化执行此SQL。

首先，您必须实现自定义初始化程序：

 code> public class MyInitializer：CreateDatabaseIfNotExists< MyContext> 
 {
 protected override void Seed（MyContext context）
 {
 context.Database.SqlCommand（CREATE INDEX IX_Person_Name ON Person（Name））; 
} 
} 
  

然后你必须注册新的初始化器：

  DbDatabase.SetInitializer< MyContext>（new MyInitializer（））; 
  

I have a table Person: id, name

I often have queries like:

select * from Person where name Like "%abc%".

I have 2 questions:

1. How do I implement this query using code-first 5 (CTP5)
2. How do I add an index on the name column to make data retrieval faster based on name like in the query?

解决方案

Like operator can be performed with Contains function:

var query = from p in context.Persons
            where p.Name.Contains("abc")
            select p;

Index must be added by SQL - there is no special construction in EF to create index. You can execute this SQL from DB initialization.

First you must implement custom initializer:

public class MyInitializer : CreateDatabaseIfNotExists<MyContext>
{
  protected override void Seed(MyContext context)
  {
    context.Database.SqlCommand("CREATE INDEX IX_Person_Name ON Person (Name)");
  }
}

Then you must register new initializer:

DbDatabase.SetInitializer<MyContext>(new MyInitializer());

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