使用System.Data.SQLite及其EF模块操作SQLite数据库（文件）

Posted 2021-01-15 wyp1988

• SQLite
  • SQLite is a self-contained, high-reliability, embedded, full-featured, public-domain, SQL database engine.
  • https://www.sqlite.org/index.html
  • License: Public Domain, Open-Source, not Open-Contribution
• SQLite for .NET (System.Data.SQLite)
  • introduction
  • An ADO.NET provider for SQLite including EF and Linq functions.
  • http://system.data.sqlite.org/index.html/doc/trunk/www/index.wiki
  • Developed by SQLite Development Team
  • License: Public Domain, Open-Source, not Open-Contribution
  • how to use
    • Add references (Nuget to find “System.Data.SQLite”)
      • EntityFramework (can be upgraded to 6.2.0, already include EF and Linq)
      • System.Data.SQLite
      • System.Data.SQLite.Core
      • System.Data.SQLite.EF6 (can be removed)
      • System.Data.SQLite.Linq (can be removed)
    • Setup configuration file (in App.config)
      • connection string
      • db provider
    • Create custom context class

在App.Config或Web.config文件中配置数据库的连接字符串及使用到的Provider：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <configuration>
 3   <configSections>
 4     <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
 5     <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false"/>
 6   </configSections>
 7   <connectionStrings>
 8     <add name="PresetDataConnectionString" connectionString="data source=PresetData.db" providerName="System.Data.SQLite"/>
 9   </connectionStrings>
10   <entityFramework>
11     <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
12       <parameters>
13         <parameter value="v13.0"/>
14       </parameters>
15     </defaultConnectionFactory>
16     <providers>
17       <provider invariantName="System.Data.SQLite" type="System.Data.SQLite.EF6.SQLiteProviderServices, System.Data.SQLite.EF6"/>
18     </providers>
19   </entityFramework>
20   <system.data>
21     <DbProviderFactories>
22       <remove invariant="System.Data.SQLite"/>
23       <add name="SQLite Data Provider" invariant="System.Data.SQLite" description=".NET Framework Data Provider for SQLite" type="System.Data.SQLite.SQLiteFactory, System.Data.SQLite"/>
24     </DbProviderFactories>
25   </system.data>
26   <startup>
27     <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.2"/>
28   </startup>
29 </configuration>

 

自定义Context类，用于操作数据库：

 1     /// <summary>
 2     /// Code First mode to use EF, on behalf of one DB
 3     /// </summary>
 4     public class UserDataContext : DbContext
 5     {
 6         public DbSet<FavoriteData> FavoriteDatas { get; set; }
 7 
 8         public UserDataContext(string connectionString)
 9             : base(new SQLiteConnection() { ConnectionString = connectionString }, true)
10         {
11 
12         }
13 
14         /// <summary>
15         /// avoid "no such table error" of __MigrationHistory and EdmMetadata in EF Code-First Mode
16         /// </summary>
17         static UserDataContext()
18         {
19             Database.SetInitializer<PresetDataContext>(null);
20         }
21 
22         /// <summary>
23         /// dummy code so that the compiler would detect that the reference is being used.
24         /// make sure projects like VisualXml and VisualXml.Test have related dlls in output bin folder
25         /// </summary>
26         private static void FixProvidersNotAutoLoadProblem()
27         {
28             var _ = typeof(System.Data.SQLite.EF6.SQLiteProviderFactory);
29             var __ = typeof(System.Data.SQLite.SQLiteFactory);
30             //var ___ = typeof(System.Data.Entity.SqlServer.SqlProviderServices);
31         }
32 
33         /// <summary>
34         /// remove restriction of DbSet field names based on table names
35         /// </summary>
36         /// <param name="modelBuilder"></param>
37         protected override void OnModelCreating(DbModelBuilder modelBuilder)
38         {
39             modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
40 
41             //modelBuilder.Configurations.AddFromAssembly(typeof(DefaultContext).Assembly);
42             //modelBuilder.Configurations.AddFromAssembly(Assembly.GetExecutingAssembly());
43         }
44     }

 

也可以动态设置数据库连接字符串：

1             SQLiteConnectionStringBuilder builder = SQLiteFactory.Instance.CreateConnectionStringBuilder() as SQLiteConnectionStringBuilder;
2 
3             // set up connection string for user data db in code
4             builder.DataSource = userDataDBFilePath;
5             builder.Password = GenerateEncryptedDBPwd();
6             UserDataContext userDataDB = new UserDataContext(builder.ToString());