假设底层数据库是MSSQL，这将比任何涉及删除单个实体对象的操作都要好得多。

foreach (var tableName in listOfTableNames)
{
    context.ExecuteStoreCommand("TRUNCATE TABLE [" + tableName + "]");
}

当然，如果表具有外键关系，则需要按正确的顺序设置表名列表，以便在清除外键表之前清除它们可能依赖的主键表。

对于懒惰的人，我在寻找答案时自己想出了代码：

public static void ClearDatabase<T>() where T : DbContext, new()
{
    using (var context = new T())
    {
        var tableNames = context.Database.SqlQuery<string>("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE =  BASE TABLE  AND TABLE_NAME NOT LIKE  %Migration% ").ToList();
        foreach (var tableName in tableNames)
        {
            context.Database.ExecuteSqlCommand(string.Format("DELETE FROM {0}", tableName));
        }

        context.SaveChanges();
    }
}

Short explanation: I do not truncate tables due to lack of permissions, if it’s not a problem for you, feel free to do so. The table __MigrationHistory is ignored by the where statement.

更新：经过一些研究，我想出了更好的解决方案（虽然不太好，但只删除了必需的列）：

public static void ClearDatabase(DbContext context)
{
    var objectContext = ((IObjectContextAdapter)context).ObjectContext;
    var entities = objectContext.MetadataWorkspace.GetEntityContainer(objectContext.DefaultContainerName, DataSpace.CSpace).BaseEntitySets;
    var method = objectContext.GetType().GetMethods().First(x => x.Name == "CreateObjectSet");
    var objectSets = entities.Select(x => method.MakeGenericMethod(Type.GetType(x.ElementType.FullName))).Select(x => x.Invoke(objectContext, null));
    var tableNames = objectSets.Select(objectSet => (objectSet.GetType().GetProperty("EntitySet").GetValue(objectSet, null) as EntitySet).Name).ToList();

    foreach (var tableName in tableNames)
    {
        context.Database.ExecuteSqlCommand(string.Format("DELETE FROM {0}", tableName));
    }

    context.SaveChanges();
}

对于EF 6：

DbSet<Entity>.RemoveRange(DbSet<Entity>);

使用如下代码遍历表：

context.GetType().GetProperties()
.Where(propertyInfo => propertyInfo.PropertyType == typeof(Table<>))
.Select(propertyInfo => propertyInfo.GetValue(context, null) as ITable).ToList()
.Foreach(table =>
{
    //code that deletes the actual tables records.
}
);

我想尝试改进@Wojciech Markowski的伟大回答。

If you are lazy like me and don t want to check for foreign keys constraints, you can use this method:

        private void ClearDatabase(TContext context)
    {
            // disable all foreign keys
            //context.Database.ExecuteSqlCommand("EXEC sp_MSforeachtable @command1 =  ALTER TABLE ? NOCHECK CONSTRAINT all ");

            List<string> tableNames = context.Database.SqlQuery<string>("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE =  BASE TABLE  AND TABLE_NAME NOT LIKE  %Migration% ").ToList();

            for (int i = 0; tableNames.Count>0; i++)
            {
                try
                {
                    context.Database.ExecuteSqlCommand(string.Format("DELETE FROM {0}", tableNames.ElementAt(i % tableNames.Count)));
                    tableNames.RemoveAt(i % tableNames.Count);
                    i = 0;
                }
                catch { } // ignore errors as these are expected due to linked foreign key data             
            }


            context.SaveChanges();
    }

ClearDatabase method goes over the list of tables and clean them. if FK constraint is found then catch the exception and move on to the next table. at the end all tables will be deleted.

此外，如果不介意松开所有FK约束，可以通过以下命令禁用所有约束：

context.Database.ExecuteSqlCommand("EXEC sp_MSforeachtable @command1 =  ALTER TABLE ? NOCHECK CONSTRAINT all ");

One thing more: If you want to delete all tables and not just clear them, then replace the line:

context.Database.ExecuteSqlCommand(string.Format("DELETE FROM {0}", tableNames.ElementAt(i % tableNames.Count)));

与：

context.Database.ExecuteSqlCommand(string.Format("DROP TABLE {0}", tableNames.ElementAt(i % tableNames.Count)));

我亲自在代码优先迁移的EntityFramework6上检查了这个答案。

编辑：更好的版本：

        private void ClearDatabase(MrSaleDbContext context)
    {
        //Optional: disable all foreign keys (db-schema will be loosed).
        //context.Database.ExecuteSqlCommand("EXEC sp_MSforeachtable @command1 =  ALTER TABLE ? NOCHECK CONSTRAINT all ");

        List<string> tableNames = context.Database.SqlQuery<string>("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE =  BASE TABLE  AND TABLE_NAME NOT LIKE  %Migration%  AND TABLE_NAME NOT LIKE  AspNet% ").ToList();

        for (int i = 0; tableNames.Count > 0; i++)
        {
            try
            {
                //To delete all tables and not just clean them from data, replace "DELETE FROM {0}" in "DROP TABLE {0}":
                context.Database.ExecuteSqlCommand(string.Format("DELETE FROM {0}", tableNames.ElementAt(i % tableNames.Count)));
                tableNames.RemoveAt(i % tableNames.Count);
                i = -1; //flag: a table was removed. in the next iteration i++ will be the 0 index.
            }
            catch (System.Data.SqlClient.SqlException e)   // ignore errors as these are expected due to linked foreign key data    
            {                    
                if ((i % tableNames.Count) == (tableNames.Count - 1))
                {
                    //end of tables-list without any success to delete any table, then exit with exception:
                    throw new System.Data.DataException("Unable to clear all relevant tables in database (foriegn key constraint ?). See inner-exception for more details.", e);
                }

            }

        }

catch块中的if语句检查我是否在不删除任何表的情况下到达了表列表的最后一个索引。在这种情况下，不进行无限循环，而是抛出异常并退出for。

（In.NetCore）您可以在表上使用RemoveRange，并将表本身作为Parameter。

Tablename.RemoveRange(Tablename);

truncate无法在外键内删除。

然后我做了DbContext的扩展方法。

用法很简单。

db.Ttruncates（）；//所有表删除。

db.截断（“Test1”、“Test2”）；//仅删除“Test1，Test2”表

public static class DbContextExtension
{
    public static int Truncates(this DbContext db, params string[] tables)
    {
        List<string> target = new List<string>();
        int result = 0;

        if (tables == null || tables.Length == 0)
        {
            target = db.GetTableList();
        }
        else
        {
            target.AddRange(tables);
        }

        using (TransactionScope scope = new TransactionScope())
        {
            foreach (var table in target)
            {
                result += db.Database.ExecuteSqlCommand(string.Format("DELETE FROM  [{0}]", table));
                db.Database.ExecuteSqlCommand(string.Format("DBCC CHECKIDENT ([{0}], RESEED, 0)", table));
            }
            
            scope.Complete();
        }

        return result;
    }

    public static List<string> GetTableList(this DbContext db)
    {
        var type = db.GetType();

        return db.GetType().GetProperties()
            .Where(x => x.PropertyType.Name == "DbSet`1")
            .Select(x => x.Name).ToList();
    }
}

这对我有用…EF v3.1.5

context.ModelName.RemoveRange(context.ModelName.ToList());
context.SaveChanges();

我想贡献我的一份力量。

我提出了这个问题，这正是作者所要求的。这是.NET 5。

var query = "sp_MSforeachtable  ALTER TABLE ? NOCHECK CONSTRAINT ALL; SET QUOTED_IDENTIFIER ON; DELETE FROM ?; ALTER TABLE ? CHECK CONSTRAINT ALL; "
context.Database.ExecuteSqlRaw(query);