SQL Server switch clustered table - sql-server

Question

I wrote the next script in SQL Server 2012, but it fails on constraint.
I have a table with 20 000 000 rows.
I created the same table with same index with partition, but when I switched
the table, SQL Server failed
Here is my code:
CREATE DATABASE test
USE test
create Partition Function
[PF_Table_Log] ([DATETIME2](3)) As Range left For VALUES
('2016-04-05 00:00:00.000','2016-04-06 00:00:00.000',
'2016-04-07 00:00:00.000','2016-04-08 00:00:00.000')
Create Partition Scheme PS_Table_Log_Datetime
As Partition [PF_Table_Log]
All To ([Primary]);
create TABLE [Log](
[LogId] [BIGINT] IDENTITY(1,1) NOT NULL,
[ServiceInstanceId] [UNIQUEIDENTIFIER] NULL,
[ServiceId] [UNIQUEIDENTIFIER] NOT NULL,
[Component] [NVARCHAR](100) NULL,
[MachineName] [NVARCHAR](50) NULL,
[Datetime] [DATETIME2](3) NOT NULL,
[Severity] [INT] NOT NULL,
[LogText] [NVARCHAR](max) NULL,
[MessageId] [UNIQUEIDENTIFIER] NULL,
[MessageRole] [INT] NULL
) ON [PRIMARY]
GO
CREATE CLUSTERED INDEX [PK_Log] ON [Log]
(
[LogId] ASC,
[datetime] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF,
DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON,ALLOW_PAGE_LOCKS=ON)
GO
create TABLE [Log_new1](
[LogId] [BIGINT] IDENTITY(1,1) NOT NULL,
[ServiceInstanceId] [UNIQUEIDENTIFIER] NULL,
[ServiceId] [UNIQUEIDENTIFIER] NOT NULL,
[Component] [NVARCHAR](100) NULL,
[MachineName] [NVARCHAR](50) NULL,
[Datetime] [DATETIME2](3) NOT NULL,
[Severity] [INT] NOT NULL,
[LogText] [NVARCHAR](max) NULL,
[MessageId] [UNIQUEIDENTIFIER] NULL,
[MessageRole] [INT] NULL
) ON PS_Table_Log_Datetime (datetime)
GO
CREATE CLUSTERED INDEX [PK_Log] ON [Log_new1]
(
[LogId] ASC,[Datetime] asc
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF,
) ON PS_Table_Log_Datetime ([Datetime])
ALTER TABLE [Log] SWITCH TO [Log_new1] PARTITION 5

Answer 1

"I created the same table with same index with partition, but when I
switched the table, SQL Server failed"
This statement isn't consistent with the script. Table Log is not partitioned but Log_new1 is. You need to either partition Log using the same partition scheme or create a check constraint on the Log table datetime column matching the target partition boundaries. The required check constraint definition for the last partition is:
ALTER TABLE Log ADD CONSTRAINT CK_Log_Datetime CHECK (Datetime > '2016-04-08 00:00:00.000');