Database数据库的分库分表，表映射，切换表，使用到了IModelCacheKeyFactory
代码如下：
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
namespace EFCOREDB
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Hello World!");
#region 测试
TestDBContext();
#endregion
Console.Read();
}
#region Database数据库操作
/// <summary>
/// 测试数据库的分库分表，表映射，切换表
/// </summary>
static void TestDBContext()
{
#region DBContext
//DateTime datetime1 = DateTime.Now;
//using (var context = new DynamicContext { CreateDateTime = datetime1 })
//{
// Console.WriteLine("开始删除数据库");
// context.Database.EnsureDeleted();
// Console.WriteLine("删除成功");
// Console.WriteLine("开始创建数据库");
// context.Database.EnsureCreated();
// Console.WriteLine("创建成功");
// var tablename = context.Model.FindEntityType(typeof(Test)).GetTableName();
// #region MyRegion
// //context.Tests.Add(new Test { Title = "Great News One", Content = $"Hello World! I am the news of {datetime1}", CreateDateTime = datetime1 });
// //更新实体的方式
// //0、查询实体，修改实体字段，context.SaveChanges();
// //1、创建实体，context.Entry(创建的实体).State=EntityState.Modified; context.SaveChanges();
// //2、创建实体，context.Update(创建的实体); context.SaveChanges();
// //3、创建实体，context.DbSet<Test>.Attach(创建的实体); context.Entry(创建的实体).State=EntityState.Modified; context.SaveChanges();
// //3、创建实体，context.DbSet<Test>.Attach(创建的实体); context.ChangeTracker.DetectChanges(); context.SaveChanges();
// //3、创建实体，context.Attach(创建的实体); context.Entry(创建的实体).State=EntityState.Modified; context.SaveChanges();
// //4、context.ChangeTracker.TrackGraph(ss, e => {
// // if ((e.Entry.Entity as Test) != null)
// // {
// // e.Entry.State = EntityState.Unchanged;
// // }
// // else
// // {
// // e.Entry.State = EntityState.Modified;
// // }
// //});
// //context.SaveChanges();
// #endregion
// var ss = new Test { Title = "11", Content = $"111 {datetime1}", CreateDateTime = datetime1 };
// Console.WriteLine($"context.Entry(ss).State:{context.Entry(ss).State}");
// //context.Attach(ss);//告诉EF Core开始跟踪person实体的更改，因为调用DbContext.Attach方法后，EF Core会将person实体的State值（可以通过testDBContext.Entry(ss).State查看到）更改回EntityState.Unchanged，所以这里testDBContext.Attach(ss)一定要放在下面一行testDBContext.Entry(ss).Property(p => p.Content).IsModified = true的前面，否者后面的testDBContext.SaveChanges方法调用后，数据库不会被更新
// //context.Entry(ss).Property(p => p.Content).IsModified = true;//告诉EF Core实体ss的Content属性已经更改。将testDBContext.Entry(person).Property(p => p.Name).IsModified设置为true后，也会将ss实体的State值（可以通过testDBContext.Entry(ss).State查看到）更改为EntityState.Modified，这样就保证了下面SaveChanges的时候会将ss实体的Content属性值Update到数据库中。
// //context.Entry(ss).Property(p => p.Content).IsModified = true;
// //context.Tests.Attach(ss);
// context.Attach(ss);
// Console.WriteLine($"context.Entry(ss).State:{context.Entry(ss).State}");
// //context.ChangeTracker.DetectChanges();
// context.SaveChanges();
//}
////切换表
//DateTime datetime2 = DateTime.Now.AddDays(-1);
//using (var context = new DynamicContext { CreateDateTime = datetime2 })
//{
// var tablename = context.Model.FindEntityType(typeof(Test)).GetTableName();//查询实体映射到数据库中对应的表名称
// if (!tablename.Equals("20201118"))
// {
// //var str = GetMySQLSqls(datetime2);
// var str = GetSqlServerSqls(datetime2);
// //判断是否存在表，不存在则创建
// using var cmd = context.Database.GetDbConnection().CreateCommand();
// cmd.CommandText = str[0];
// if (cmd.Connection.State != System.Data.ConnectionState.Open)
// {
// cmd.Connection.Open();
// }
// var result = cmd.ExecuteScalar();
// if (result.ToString() == "0")
// {
// //创建新表
// context.Database.ExecuteSqlRaw(str[1]);
// }
// }
// //context.Database.EnsureCreated();
// context.Tests.Add(new Test { Title = "22", Content = $"222 {datetime2}", CreateDateTime = datetime2 });
// context.SaveChanges();
//}
//using (var context = new DynamicContext { CreateDateTime = datetime1 })
//{
// var entity = context.Tests.Single();
// // Writes news of today
// Console.WriteLine($"{entity.Title} {entity.Content} {entity.CreateDateTime}");
//}
//using (var context = new DynamicContext { CreateDateTime = datetime2 })
//{
// var entity = context.Tests.Single();
// // Writes news of yesterday
// Console.WriteLine($"{entity.Title} {entity.Content} {entity.CreateDateTime}");
//}
#endregion
}
#region Database数据库操作
private static string[] GetMySQLSqls(DateTime time)
{
string tableName = time.ToString("yyyyMMdd");
string decide = $"SELECT count(1) FROM information_schema.TABLES WHERE table_name='{tableName}'";
string sqlRaw = $@"
CREATE TABLE IF NOT EXISTS `{tableName}` (
`Id` int(20) NOT NULL,
`Title` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL,
`Content` varchar(500) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL,
`CreateDateTime` datetime(6) NOT NULL,
PRIMARY KEY (`Id`),
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
";
return new string[] { decide, sqlRaw };
}
private static string[] GetSqlServerSqls(DateTime time)
{
//注意：[Id] int NOT NULL IDENTITY(1,1)中的 IDENTITY(1,1) 表示自增
string tableName = time.ToString("yyyyMMdd");
//-- 判断要创建的表名是否存在 select * from dbo.sysobjects where id=object_id(N'[dbo].[{0}]') and xtype='U'
string decide = $"SELECT COUNT(1) FROM dbo.sysobjects WHERE id = object_id(N'[dbo].[{tableName}]') and OBJECTPROPERTY(id, N'IsUserTable') = 1";
string sqlRaw = $@"IF NOT EXISTS ( SELECT * FROM dbo.sysobjects WHERE id=object_id(N'[dbo].[{tableName}]') AND xtype='U')
BEGIN
CREATE TABLE [dbo].[{tableName}] (
[Id] int NOT NULL IDENTITY(1,1),
[Title] nvarchar(20) NULL ,
[Content] nvarchar(500) NULL ,
[CreateDateTime] datetime2(7) NOT NULL ,
);
ALTER TABLE [dbo].[{tableName}] ADD PRIMARY KEY ([Id]);
END";
return new string[] { decide, sqlRaw };
}
private static string[] GetOracleSqls(string defaultSchema, DateTime time)
{
string tableName = time.ToString("yyyyMMdd");
string schema = defaultSchema;
string id_seq = $"{tableName}_id_seq";
var pk = $"PK_{tableName}";
string decide = $"SELECT COUNT(1) FROM all_tables WHERE TABLE_NAME='{tableName}' AND OWNER='{schema}'";
string sqlRaw =
$@"DECLARE num NUMBER;
BEGIN
SELECT
COUNT(1) INTO num
FROM
all_tables
WHERE
TABLE_NAME = '{tableName}'
AND OWNER = '{schema}';
IF
num = 0 THEN
EXECUTE IMMEDIATE 'CREATE TABLE ""{schema}"".""{tableName}"" (
""Id"" NUMBER(10) NOT NULL,
""Title"" NVARCHAR2(20),
""Content"" NCLOB,
""CreateDateTime"" TIMESTAMP(7) NOT NULL,
CONSTRAINT ""{pk}"" PRIMARY KEY(""Id""),
)';
EXECUTE IMMEDIATE 'CREATE SEQUENCE ""{schema}"".""{id_seq}"" START WITH 1 INCREMENT BY 1';
END IF;
END; ";
return new string[] { decide, sqlRaw };
}
#endregion
#endregion
}
public class Test
{
public int Id { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public DateTime CreateDateTime { get; set; }
}
public class DynamicContext : DbContext
{
public DateTime CreateDateTime { get; set; }//为了区分不同的表
public DbSet<Test> Tests { get; set; }
//sqlserver连接字符串 Server=(localdb)\\mssqllocaldb;Database=DynamicContext;Trusted_Connection=True;
//sqlserver连接字符串 server=127.0.0.1;database=DynamicContext;user=zy;password=zy;
//oracle连接字符串 Data Source=127.0.0.1:1521/orcl;User Id=zy;Password=zy;
//"DbConnectString": "Data Source=127.0.0.1:1521/orcl;User Id=zy;Password=zy;",
//"DefaultSchema": "ZY",
//"DbVersion": "11",
//mysql连接字符串 server=127.0.0.1;database=DynamicContext;user=zy;password=zy;
//public static string DbConnectString = "(localdb)\\mssqllocaldb;Database=DynamicContext;Trusted_Connection=True;";
//如果是oracle的话，Oracle连接字符串中并不包含数据名称，其实DefaultSchema就是数据库名称，音系需要下面的两个DefaultSchema，DbVersion字段
public static string DefaultSchema = "ZY";//
public static string DbVersion = "11";
DbType dbType = DbType.SqlServer;
#region OnConfiguring
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
switch (dbType)
{
case DbType.SqlServer:
string DbConnectStringSqlServer = "(localdb)\\mssqllocaldb;Database=DynamicContext;Trusted_Connection=True;";
DbConnectStringSqlServer = "server=127.0.0.1;database=DynamicContext;user=zy;password=zy;";
DbConnectStringSqlServer = "server=127.0.0.1;database=DynamicContext;user=sa;password=sa123;";
optionsBuilder.UseSqlServer(DbConnectStringSqlServer)
.ReplaceService<IModelCacheKeyFactory, DynamicModelCacheKeyFactory>();
break;
case DbType.MySql:
string DbConnectStringMySql = "server=127.0.0.1;database=DynamicContext;user=zy;password=zy;";
DbConnectStringMySql = "server=127.0.0.1;database=DynamicContext;user=root;password=123456;";
optionsBuilder.UseMySql(DbConnectStringMySql)
.ReplaceService<IModelCacheKeyFactory, DynamicModelCacheKeyFactory>();
break;
case DbType.Oracle:
string DbConnectStringOracle = "Data Source=127.0.0.1:1521/orcl;User Id=zy;Password=zy;";
optionsBuilder.UseOracle(DbConnectStringOracle, t => t.UseOracleSQLCompatibility(DbVersion))
.ReplaceService<IModelCacheKeyFactory, DynamicModelCacheKeyFactory>();
break;
default:
throw new Exception("数据库不匹配。。。");
}
}
//=> optionsBuilder.UseMySql(DbConnectString).ReplaceService<IModelCacheKeyFactory, DynamicModelCacheKeyFactory>();
//=> optionsBuilder.UseOracle(DbConnectString).ReplaceService<IModelCacheKeyFactory, DynamicModelCacheKeyFactory>();
//=> optionsBuilder.UseSqlServer(DbConnectString).ReplaceService<IModelCacheKeyFactory, DynamicModelCacheKeyFactory>();
//protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
//=> optionsBuilder.UseInMemoryDatabase("DynamicContext")
//.ReplaceService<IModelCacheKeyFactory, DynamicModelCacheKeyFactory>();
#endregion
#region OnModelCreating
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
if (Database.IsOracle())
{
modelBuilder.HasDefaultSchema(DefaultSchema);
}
modelBuilder.Entity<Test>(b =>
{
b.ToTable(CreateDateTime.ToString("yyyyMMdd"));
b.HasKey(p => p.Id);
//b.Property(p => p.Id).HasColumnType("int").ValueGeneratedOnAdd();
//b.Property(p => p.Id).HasColumnType("int");
b.Property(p => p.Title).HasMaxLength(20);
b.Property(p => p.Content).HasMaxLength(500);
});
}
#endregion
}
public enum DbType
{
SqlServer,
MySql,
Oracle
}
public class DynamicModelCacheKeyFactory : IModelCacheKeyFactory
{
public object Create(DbContext context) => context is DynamicContext dynamicContext ? (context.GetType(), dynamicContext.CreateDateTime) : (object)context.GetType();
}
}
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