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标题: C# 使用EntityFramework CodeFirst 创建PostgreSQL数据库 [打印本页]
作者: 农民    时间: 2023-7-26 08:44
标题: C# 使用EntityFramework CodeFirst 创建PostgreSQL数据库
1.先创建一个ASP.Net Web应用程序，选择Web API

 2、创建EntityLib、EF、AppService三个类库。EntityLib用于存放数据库表所对应的实体，AppService用于编写用户对实体的一些操作方法，如增删改查等操作。

 创建好所有类库之后，需要添加引用库EntityFramework6.Npgsql，右击项目中的引用———》管理NuGet程序包———》搜索EntityFramework6.Npgsql添加到项目中，这个库会自动添加EntityFramework6和Npgsql的引用。需要给EF、AppService和API都添加这个引用。添加完成之后就开始写各个类库相应的代码了。
 
EFContext类
  1. public class EFContext : DbContext
  2.     {
  3.         public EFContext() : base("Postgresql")//连接字符串名称
  4.         {
  6.         }
  7.         protected override void OnModelCreating(DbModelBuilder modelBuilder)
  8.         {
  9. <connectionStrings>
  10.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  11.     </connectionStrings>modelBuilder.HasDefaultSchema("public");//EF默认创建到dbo架构中，而PostgreSQL默认为public架构
  12. <connectionStrings>
  13.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  14.     </connectionStrings>modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
  15. <connectionStrings>
  16.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  17.     </connectionStrings>base.OnModelCreating(modelBuilder);
  18.         }
  19.         public DbSet<User> Users { get; set; }
  20.     }
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 User类
  1. [Table("User",Schema ="public")]
  2.     public class User
  3.     {
  4.         [Key]
  5.         [Required]
  6.         [Column("ID")]
  7.         public int ID { get; set; }
  9.         public string Name { get; set; }
  11.         public string Account { get; set; }
  13.         public string Password { get; set; }
  14.     }
复制代码
 
AppService类
  1. public class UserService
  2.     {
  3.         public void AddUser(User user)
  4.         {
  5. <connectionStrings>
  6.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  7.     </connectionStrings>try
  8. <connectionStrings>
  9.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  10.     </connectionStrings>{
  11. <connectionStrings>
  12.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  13.     </connectionStrings>    using (var db = new EFContext())
  14. <connectionStrings>
  15.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  16.     </connectionStrings>    {
  18. <connectionStrings>
  19.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  20.     </connectionStrings>        db.Users.Add(user);
  21. <connectionStrings>
  22.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  23.     </connectionStrings>        db.SaveChanges();
  24. <connectionStrings>
  25.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  26.     </connectionStrings>    }
  27. <connectionStrings>
  28.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  29.     </connectionStrings>}
  30. <connectionStrings>
  31.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  32.     </connectionStrings>catch (Exception e)
  33. <connectionStrings>
  34.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  35.     </connectionStrings>{
  36. <connectionStrings>
  37.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  38.     </connectionStrings>    string msg = e.Message;
  39. <connectionStrings>
  40.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  41.     </connectionStrings>}
  42.         }
  44.         public void DeleteUserByID(int id)
  45.         {
  46. <connectionStrings>
  47.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  48.     </connectionStrings>try
  49. <connectionStrings>
  50.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  51.     </connectionStrings>{
  52. <connectionStrings>
  53.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  54.     </connectionStrings>    using (var db = new EFContext())
  55. <connectionStrings>
  56.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  57.     </connectionStrings>    {
  59. <connectionStrings>
  60.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  61.     </connectionStrings>        db.Users.Remove(db.Users.Find(id));
  62. <connectionStrings>
  63.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  64.     </connectionStrings>        db.SaveChanges();
  65. <connectionStrings>
  66.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  67.     </connectionStrings>    }
  68. <connectionStrings>
  69.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  70.     </connectionStrings>}
  71. <connectionStrings>
  72.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  73.     </connectionStrings>catch (Exception e)
  74. <connectionStrings>
  75.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  76.     </connectionStrings>{
  77. <connectionStrings>
  78.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  79.     </connectionStrings>    string msg = e.Message;
  80. <connectionStrings>
  81.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  82.     </connectionStrings>}
  83.         }
  85.         public void EditUser(User user)
  86.         {
  87. <connectionStrings>
  88.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  89.     </connectionStrings>try
  90. <connectionStrings>
  91.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  92.     </connectionStrings>{
  93. <connectionStrings>
  94.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  95.     </connectionStrings>    using (var db = new EFContext())
  96. <connectionStrings>
  97.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  98.     </connectionStrings>    {
  99. <connectionStrings>
  100.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  101.     </connectionStrings>        
  102. <connectionStrings>
  103.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  104.     </connectionStrings>        User u = db.Users.Find(user.ID);
  105. <connectionStrings>
  106.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  107.     </connectionStrings>        u.Name = user.Name;
  108. <connectionStrings>
  109.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  110.     </connectionStrings>        u.Account = user.Account;
  111. <connectionStrings>
  112.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  113.     </connectionStrings>        u.Password = user.Password;
  114. <connectionStrings>
  115.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  116.     </connectionStrings>        db.SaveChanges();
  117. <connectionStrings>
  118.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  119.     </connectionStrings>    }
  120. <connectionStrings>
  121.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  122.     </connectionStrings>}
  123. <connectionStrings>
  124.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  125.     </connectionStrings>catch (Exception e)
  126. <connectionStrings>
  127.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  128.     </connectionStrings>{
  129. <connectionStrings>
  130.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  131.     </connectionStrings>    string msg = e.Message;
  132. <connectionStrings>
  133.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  134.     </connectionStrings>}
  135.         }
  137.         public User FindUserByID(int id)
  138.         {
  139. <connectionStrings>
  140.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  141.     </connectionStrings>try
  142. <connectionStrings>
  143.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  144.     </connectionStrings>{
  145. <connectionStrings>
  146.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  147.     </connectionStrings>    using (var db = new EFContext())
  148. <connectionStrings>
  149.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  150.     </connectionStrings>    {
  152. <connectionStrings>
  153.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  154.     </connectionStrings>        User user = db.Users.Find(id);
  155. <connectionStrings>
  156.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  157.     </connectionStrings>        return user;
  158. <connectionStrings>
  159.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  160.     </connectionStrings>    }
  161. <connectionStrings>
  162.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  163.     </connectionStrings>}
  164. <connectionStrings>
  165.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  166.     </connectionStrings>catch (Exception e)
  167. <connectionStrings>
  168.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  169.     </connectionStrings>{
  170. <connectionStrings>
  171.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  172.     </connectionStrings>    string msg = e.Message;
  173. <connectionStrings>
  174.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  175.     </connectionStrings>    return null;
  176. <connectionStrings>
  177.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  178.     </connectionStrings>}
  179.         }
  181.         public List<User> FindAll()
  182.         {
  183. <connectionStrings>
  184.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  185.     </connectionStrings>try
  186. <connectionStrings>
  187.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  188.     </connectionStrings>{
  189. <connectionStrings>
  190.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  191.     </connectionStrings>    using (var db = new EFContext())
  192. <connectionStrings>
  193.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  194.     </connectionStrings>    {
  196. <connectionStrings>
  197.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  198.     </connectionStrings>        List<User> users = db.Users.ToList();
  199. <connectionStrings>
  200.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  201.     </connectionStrings>        return users;
  202. <connectionStrings>
  203.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  204.     </connectionStrings>    }
  205. <connectionStrings>
  206.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  207.     </connectionStrings>}
  208. <connectionStrings>
  209.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  210.     </connectionStrings>catch (Exception e)
  211. <connectionStrings>
  212.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  213.     </connectionStrings>{
  214. <connectionStrings>
  215.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  216.     </connectionStrings>    string msg = e.Message;
  217. <connectionStrings>
  218.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  219.     </connectionStrings>    return null;
  220. <connectionStrings>
  221.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  222.     </connectionStrings>}
  223.         }
  224.     }
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完成类的编写之后，需要添加数据库连接字符串，打开API的web.config文件添加：
  1. <connectionStrings>
  2.         <add name="Postgresql" connectionString="PORT=502;DATABASE=postgres;HOST=10.60.140.1;PASSWORD=007;USER ID=postgres" providerName="Npgsql" />
  3.     </connectionStrings>
复制代码
 3.进行数据迁移，通过命令将实体类导入数据库生成相应的数据库表。先打开VS的工具，然后点击NuGet包管理器 ，选择程序包管理器控制台，默认项目改为EF,输入以下三行命令

1-》enable-migrations  
2-》add-migration 
3-》update-database
 
去PostgreSQL数据库去查看发现已经生成好了数据库和对应的表了，这里因为我postgres数据库已经有User表了，所以修改了一下数据库连接字符串

 

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