EF6 在 SQLite中使用备忘

== 菜鸟级选手试验在EF6中使用Sqlite，零EF基础，少量Sqlite基础。经过断断续续的很长时间 - _ -！

>>连接

1. 安装

   使用目前最新版本EF6.1，Sqlite1.0.93.0。直接NuGet安装：

   

2. 配置

<?xml version= "1.0" encoding= "utf-8" ?>
<configuration>
  <configSections>
    <section name= "entityFramework" type= "System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission= "false" />
    <!-- For more information on Entity Framework configuration, visit http: //go.microsoft.com/fwlink/?LinkID=237468 -->
  </configSections>
  <startup>
    <supportedRuntime version= "v4.0" sku= ".NETFramework,Version=v4.5" />
  </startup>
  <connectionStrings>
    <add name= "SqlliteEF6" connectionString= "Data Source=Data\EF6.db" providerName= "System.Data.SQLite" />    </connectionStrings>
  <entityFramework>
    <providers>
      <provider invariantName= "System.Data.SQLite" type= "System.Data.SQLite.EF6.SQLiteProviderServices, System.Data.SQLite.EF6" />
      <provider invariantName= "System.Data.SQLite.EF6" type= "System.Data.SQLite.EF6.SQLiteProviderServices, System.Data.SQLite.EF6" />
    </providers>
    <defaultConnectionFactory type= "System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework" >
      <parameters>
        <parameter value= "v11.0" />
      </parameters>
    </defaultConnectionFactory>
  </entityFramework>
  <system.data>
    <DbProviderFactories>
      <remove invariant= "System.Data.SQLite" />
      <add name= "SQLite Data Provider" invariant= "System.Data.SQLite" description= "Data Provider for SQLite" type= "System.Data.SQLite.SQLiteFactory, System.Data.SQLite" />
      <remove invariant= "System.Data.SQLite.EF6" />
      <add name= "SQLite Data Provider (Entity Framework 6)" invariant= "System.Data.SQLite.EF6" description= ".Net Framework Data Provider for SQLite (Entity Framework 6)" type= "System.Data.SQLite.EF6.SQLiteProviderFactory, System.Data.SQLite.EF6" />
    </DbProviderFactories>
  </system.data>
</configuration>

 3. 设置数据库

    EF中数据库操作继承DBContext。需要指定数据连接，名称和config配置一致，否则默认使用Sqlserver。

    SQLite可以重载创建。

 

public  class  EF6Context : DbContext
    {
        public  EF6Context( string  databaseName =  "SqlliteEF6" )
            :  base (databaseName)
        {
        }

        public  DbSet<User> Users {  set ;  get ; }

        protected  override  void  OnModelCreating(DbModelBuilder modelBuilder)
        {}
    }

 

  

>>注意事项

1. Sqlite中不能自动创建数据库和新建表，需要额外的操作

>> 数据类型插入获取

1. 自增ID

   Sqlite中需要设置AUTOINCREMENT，如下：

Id INTEGER PRIMARY KEY AUTOINCREMENT,

需要引用System.ComponentModel.DataAnnotations，System.ComponentModel.DataAnnotations.Schema，类中写明

[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Int64 Id { get ; set ; }

2. 限定Table

  默认数据库获取为DBContext中定义的名称，限定对应的Table，需要在类上指明，如下：

[Table( "User" )]
public class User
{...

3. 枚举型

   目前直接能使用，注意需要在定义表时限定不能为NULL,否则为NULL时获取会报错。定义时如下定义：

public enum TestENUM : long { A, B, C };

 

4. 其它

   目前SQlite中支持浮点数、时间、二进制数据、字符串等。创建表示例：

NorthwindContext context = new NorthwindContext();
           string sql = @" CREATE TABLE User (
   Id INTEGER PRIMARY KEY AUTOINCREMENT,
   Name varchar (20),
   Time timestamp,
   Data blob,
   Val REAL,
   TestE INTEGER);" ;
           context.Database.ExecuteSqlCommand(sql, new object [1]);

   定义类示例：

[Table( "User" )]
public class User
{
    public enum TestENUM : long { A, B, C };

    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public Int64 Id { get ; set ; }
    [StringLength(30)]
    public string Name { get ; set ; }

    public byte [] Data { get ; set ; }

    public double Val { get ; set ; }

    public DateTime Time { get ; set ; }
    public TestENUM TestE { get ; set ; }
}

  

public  class  EF6Context : DbContext
    {
        public  EF6Context( string  databaseName =  "SqlliteEF6" )
            :  base (databaseName)
        {
        }

        public  DbSet<User> Users {  set ;  get ; }

        protected  override  void  OnModelCreating(DbModelBuilder modelBuilder)
        {}
    }

 

     调用示例：

 

NorthwindContext context = new NorthwindContext();
context.Users.Add( new User() { Data = new byte [] { 1, 2, 3, 4 }, Name = "aa22" , Time = DateTime.Now, Val = 2.2,  TestE    = User.TestENUM.B });
context.SaveChanges();

 

NorthwindContext context = new NorthwindContext();
context.Users.OrderBy(c => c.Name).Load();
this .dataGrid.ItemsSource = context.Users.Local;

    以上代码测试正常。源码下载

 

 

 

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