代码优先EF6的多租户

我们的组织需要一个单一的数据库，多租户
（ 通过表模式，而不是租户id ）架构。

这里有一篇很棒的文章开始介绍这类事情： http ： //romiller.com/2011/05/23/ef-4-1-multi-tenant-with-code-first/

在文章的中间，写道：

您会注意到（可能有些沮丧）我们需要编写代码来为每个实体配置表模式。 不可否认，这个代码周围没有很多神奇的独角兽……在EF的未来版本中，我们将能够用更清洁的自定义约定代替它。

我们的目标是以最干净的方式拥有一个上下文类，我们可以使用它来连接到具有相同模型的多个模式。
（ 请注意，modelBuilder.HasDefaultSchema似乎不够用 ，因为它仅适用于EF首次初始化上下文并运行OnModelCreating时）

EF5或EF6中是否存在上述清洁自定义约定？
或者是否有更清洁的方式来处理这个？

注意：我也在开发论坛上问了这个问题，因为它似乎更多地与EF的方向有关，但是想看看这里是否有人有其他选择。

注2：我不担心迁移，我们会分开处理。

Answer 1

如果在IDbModelCacheKeyProvider上实现IDbModelCacheKeyProvider ， 则 modelBuilder.HasDefaultSchema中的属性modelBuilder.HasDefaultSchema就足够了。 模型创建一次，然后由EntityFramwork内部缓存，您可以为缓存定义自己的密钥。 将模式名称作为模型缓存键，EF将根据每个不同的缓存键（在我们的示例中为模式）创建模型。 这是我的概念certificate代码：

 using System; using System.Collections.Generic; using System.Data.Entity; using System.Data.Entity.Infrastructure; using System.Linq; using System.Text; using System.Threading.Tasks; using TenantDataModel; namespace TenantDataContext { public class TenantDataCtx : DbContext, IDbModelCacheKeyProvider { #region Construction public static TenantDataCtx Create(string databaseServer, string databaseName, string databaseUserName, string databasePassword, Guid tenantId) { var connectionStringBuilder = new System.Data.SqlClient.SqlConnectionStringBuilder(); connectionStringBuilder.DataSource = databaseServer; connectionStringBuilder.InitialCatalog = databaseName; connectionStringBuilder.UserID = databaseUserName; connectionStringBuilder.Password = databasePassword; string connectionString = connectionStringBuilder.ToString(); return new TenantDataCtx(connectionString, tenantId); } // Used by EF migrations public TenantDataCtx() { Database.SetInitializer(null); } internal TenantDataCtx(string connectionString, Guid tenantId) : base(connectionString) { Database.SetInitializer(null); this.SchemaName = tenantId.ToString("D"); } public string SchemaName { get; private set; } #endregion #region DataSet Properties public DbSet TestEntities { get { return this.Set(); } } #endregion #region Overrides protected override void OnModelCreating(DbModelBuilder modelBuilder) { if (this.SchemaName != null) { modelBuilder.HasDefaultSchema(this.SchemaName); } base.OnModelCreating(modelBuilder); } #endregion #region IDbModelCacheKeyProvider Members public string CacheKey { get { return this.SchemaName; } } #endregion } } 

此外，我找到了一种使用EF迁移的方法。 我对我的解决方案并不满意，但似乎现在没有其他解决方案可用。

 using System; using System.Collections.Generic; using System.Data.Entity.SqlServer; using System.Linq; using System.Text; using System.Threading.Tasks; namespace TenantDatabaseManager { public class SqlServerSchemaAwareMigrationSqlGenerator : SqlServerMigrationSqlGenerator { private string _schema; public SqlServerSchemaAwareMigrationSqlGenerator(string schema) { _schema = schema; } protected override void Generate(System.Data.Entity.Migrations.Model.AddColumnOperation addColumnOperation) { string newTableName = _GetNameWithReplacedSchema(addColumnOperation.Table); var newAddColumnOperation = new System.Data.Entity.Migrations.Model.AddColumnOperation(newTableName, addColumnOperation.Column, addColumnOperation.AnonymousArguments); base.Generate(newAddColumnOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.AddPrimaryKeyOperation addPrimaryKeyOperation) { addPrimaryKeyOperation.Table = _GetNameWithReplacedSchema(addPrimaryKeyOperation.Table); base.Generate(addPrimaryKeyOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.AlterColumnOperation alterColumnOperation) { string tableName = _GetNameWithReplacedSchema(alterColumnOperation.Table); var newAlterColumnOperation = new System.Data.Entity.Migrations.Model.AlterColumnOperation(tableName, alterColumnOperation.Column, alterColumnOperation.IsDestructiveChange); base.Generate(newAlterColumnOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.DropPrimaryKeyOperation dropPrimaryKeyOperation) { dropPrimaryKeyOperation.Table = _GetNameWithReplacedSchema(dropPrimaryKeyOperation.Table); base.Generate(dropPrimaryKeyOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.CreateIndexOperation createIndexOperation) { string name = _GetNameWithReplacedSchema(createIndexOperation.Table); createIndexOperation.Table = name; base.Generate(createIndexOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.CreateTableOperation createTableOperation) { string newTableName = _GetNameWithReplacedSchema(createTableOperation.Name); var newCreateTableOperation = new System.Data.Entity.Migrations.Model.CreateTableOperation(newTableName, createTableOperation.AnonymousArguments); newCreateTableOperation.PrimaryKey = createTableOperation.PrimaryKey; foreach (var column in createTableOperation.Columns) { newCreateTableOperation.Columns.Add(column); } base.Generate(newCreateTableOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.RenameTableOperation renameTableOperation) { string oldName = _GetNameWithReplacedSchema(renameTableOperation.Name); string newName = renameTableOperation.NewName.Split(new char[] { '.' }).Last(); var newRenameTableOperation = new System.Data.Entity.Migrations.Model.RenameTableOperation(oldName, newName, renameTableOperation.AnonymousArguments); base.Generate(newRenameTableOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.RenameIndexOperation renameIndexOperation) { string tableName = _GetNameWithReplacedSchema(renameIndexOperation.Table); var newRenameIndexOperation = new System.Data.Entity.Migrations.Model.RenameIndexOperation(tableName, renameIndexOperation.Name, renameIndexOperation.NewName); base.Generate(newRenameIndexOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.AddForeignKeyOperation addForeignKeyOperation) { addForeignKeyOperation.DependentTable = _GetNameWithReplacedSchema(addForeignKeyOperation.DependentTable); addForeignKeyOperation.PrincipalTable = _GetNameWithReplacedSchema(addForeignKeyOperation.PrincipalTable); base.Generate(addForeignKeyOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.DropColumnOperation dropColumnOperation) { string newTableName = _GetNameWithReplacedSchema(dropColumnOperation.Table); var newDropColumnOperation = new System.Data.Entity.Migrations.Model.DropColumnOperation(newTableName, dropColumnOperation.Name, dropColumnOperation.AnonymousArguments); base.Generate(newDropColumnOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.RenameColumnOperation renameColumnOperation) { string newTableName = _GetNameWithReplacedSchema(renameColumnOperation.Table); var newRenameColumnOperation = new System.Data.Entity.Migrations.Model.RenameColumnOperation(newTableName, renameColumnOperation.Name, renameColumnOperation.NewName); base.Generate(newRenameColumnOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.DropTableOperation dropTableOperation) { string newTableName = _GetNameWithReplacedSchema(dropTableOperation.Name); var newDropTableOperation = new System.Data.Entity.Migrations.Model.DropTableOperation(newTableName, dropTableOperation.AnonymousArguments); base.Generate(newDropTableOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.DropForeignKeyOperation dropForeignKeyOperation) { dropForeignKeyOperation.PrincipalTable = _GetNameWithReplacedSchema(dropForeignKeyOperation.PrincipalTable); dropForeignKeyOperation.DependentTable = _GetNameWithReplacedSchema(dropForeignKeyOperation.DependentTable); base.Generate(dropForeignKeyOperation); } protected override void Generate(System.Data.Entity.Migrations.Model.DropIndexOperation dropIndexOperation) { dropIndexOperation.Table = _GetNameWithReplacedSchema(dropIndexOperation.Table); base.Generate(dropIndexOperation); } private string _GetNameWithReplacedSchema(string name) { string[] nameParts = name.Split('.'); string newName; switch (nameParts.Length) { case 1: newName = string.Format("{0}.{1}", _schema, nameParts[0]); break; case 2: newName = string.Format("{0}.{1}", _schema, nameParts[1]); break; case 3: newName = string.Format("{0}.{1}.{2}", _schema, nameParts[1], nameParts[2]); break; default: throw new NotSupportedException(); } return newName; } } } 

这就是我使用SqlServerSchemaAwareMigrationSqlGenerator ：

 // Update TenantDataCtx var tenantDataMigrationsConfiguration = new DbMigrationsConfiguration(); tenantDataMigrationsConfiguration.AutomaticMigrationsEnabled = false; tenantDataMigrationsConfiguration.SetSqlGenerator("System.Data.SqlClient", new SqlServerSchemaAwareMigrationSqlGenerator(schemaName)); tenantDataMigrationsConfiguration.SetHistoryContextFactory("System.Data.SqlClient", (existingConnection, defaultSchema) => new HistoryContext(existingConnection, schemaName)); tenantDataMigrationsConfiguration.TargetDatabase = new System.Data.Entity.Infrastructure.DbConnectionInfo(connectionString, "System.Data.SqlClient"); tenantDataMigrationsConfiguration.MigrationsAssembly = typeof(TenantDataContext.TenantDataCtx).Assembly; tenantDataMigrationsConfiguration.MigrationsNamespace = "TenantDataContext.Migrations.TenantData"; DbMigrator tenantDataCtxMigrator = new DbMigrator(tenantDataMigrationsConfiguration); tenantDataCtxMigrator.Update(); 

来自德国，

托比亚斯

Answer 2

非常好的方法，它帮助我得到一个更直接的解决方案。 您可以只覆盖名称方法，它在每个作家中使用….抱歉新答案，但我不允许发表评论….

 public class SqlServerSchemaAwareMigrationSqlGenerator:SqlServerMigrationSqlGenerator { private string _schema; public accountMigrationSqlGenerator(string schema) { _schema = schema; } protected override string Name(string name) { int p = name.IndexOf('.'); if(p>0) { name = name.Substring(p + 1); } return $"[{_schema}].[{name}]"; } } 

Answer 3

好吧，如果它不是代码优先，我会尝试这样做：

• 生成默认架构中的表，比如说dbo

• 基于现有数据库生成edmx

• 将EF与POCO作为起始TT模板

• 编辑TT文件并将新属性添加到称为schema上下文中，并强制生成的类中的查询将其用于数据库对象。

这样，您就可以为不同的模式创建上下文，甚至允许对象在上下文之间飞行。

Answer 4

谢谢： 托比亚斯 ！ 你救了我一年……

我在EF 6下对Oracle DB的修改：

 public class IntegrationDbContext : DbContext, IDbModelCacheKeyProvider { private static readonly ILog __log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType); /// 
 /// Factory method /// 
 public static IntegrationDbContext Create(string connectionStringName) { return new IntegrationDbContext(connectionStringName, GetDBSchema(connectionStringName)); } /// 
 /// Constructor /// 
 public IntegrationDbContext() { Database.SetInitializer(null); } /// 
 /// Constructor /// 
 internal IntegrationDbContext(string connectionString, string schemaName) : base("name={0}".Fill(connectionString)) { Database.SetInitializer(null); SchemaName = schemaName; } /// 
 /// DB schema name /// 
 public string SchemaName { get; private set; } #region Tables /// 
 /// Integration table "SYNC_BONUS_DISTRIBUTION" /// 
 public virtual DbSet SYNC_BONUS_DISTRIBUTION { get; set; } /// 
 /// Integration table "SYNC_MESSAGE_DISTRIBUTION" /// 
 public virtual DbSet SYNC_MESSAGE_DISTRIBUTION { get; set; } /// 
 /// Integration table "IMPORT_TEMPLATES" /// 
 public virtual DbSet IMPORT_TEMPLATES { get; set; } #endregion //Tables private static Dictionary __schemaCache = new Dictionary(); private static object __schCacheLock = new object(); /// 
 /// Gets DB schema name from connection string, or default from config /// 
 private static string GetDBSchema(string connectionStringName) { string result; if (!__schemaCache.TryGetValue(connectionStringName, out result)) { lock (__schCacheLock) { if (!__schemaCache.TryGetValue(connectionStringName, out result)) { DbConnectionStringBuilder builder = new DbConnectionStringBuilder(); builder.ConnectionString = ConfigurationManager.ConnectionStrings[connectionStringName].ConnectionString; result = builder.ContainsKey("User ID") ? builder["User ID"] as string : ConfigurationManager.AppSettings["DefaultIntegrationSchema"]; __schemaCache.Add(connectionStringName, result); } } } return result; } /// 
 /// Context initialization /// 
 protected override void OnModelCreating(DbModelBuilder modelBuilder) { __log.DebugFormat("OnModelCreating for integration model in schema: {0}", SchemaName); if (SchemaName != null) { modelBuilder.HasDefaultSchema(SchemaName); } //### CLOB settings modelBuilder.Properties().Where(p => p.PropertyType == typeof(string) && p.GetCustomAttributes(typeof(MaxLengthAttribute), false).Length == 0) .Configure(p => p.HasMaxLength(2000)); base.OnModelCreating(modelBuilder); } /// 
 /// Implementation of  - thanks by this is 'OnModelCreating' calling for each specific schema. /// 
 public string CacheKey { get { return SchemaName; } } }