What is the advantage of partition Date field into individual Year(int), Month(int), Day(int), Time(time) columns?
My manager said this is well known practice and query performance is good. Is this true?
Thanks in advance
Edit: and this columns are put under a clustered index.
Edit: This is not a accounting database. There is no need for thirteen month or 30 Feb.
Edit: table script
/****** Object: Table [dbo].[tbl_PlayerActionLog] Script Date: 14/8/2014 9:47:28 AM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[tbl_PlayerActionLog](
[LogId] [bigint] IDENTITY(1,1) NOT NULL,
[LogYear] [int] NOT NULL CONSTRAINT [DF_tbl_PlayerActionLog_LogYear] DEFAULT (datepart(year,sysdatetime())),
[LogMonth] [int] NOT NULL CONSTRAINT [DF_tbl_PlayerActionLog_LogMonth] DEFAULT (datepart(month,sysdatetime())),
[LogDay] [int] NOT NULL CONSTRAINT [DF_tbl_PlayerActionLog_LogDay] DEFAULT (datepart(day,sysdatetime())),
[LogTime] [time](7) NULL CONSTRAINT [DF_tbl_PlayerActionLog_LogTime] DEFAULT (sysdatetime()),
[PlayerActionTypeId] [int] NOT NULL,
[MerchantId] [int] NOT NULL,
[UserName] [varchar](50) NOT NULL,
[BetModeId] [int] NULL,
[OSVersion] [varchar](20) NULL,
[SessionId] [varchar](30) NULL,
[IpAddress] [varchar](15) NOT NULL,
[LogDetail] [nvarchar](max) NOT NULL,
CONSTRAINT [PK_tbl_PlayerActionLog] PRIMARY KEY NONCLUSTERED
(
[LogId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
SET ANSI_PADDING OFF
GO
ALTER TABLE [dbo].[tbl_PlayerActionLog] WITH CHECK ADD CONSTRAINT [FK_tbl_PlayerActionLog_tbl_LookupPlayerActionType] FOREIGN KEY([PlayerActionTypeId])
REFERENCES [dbo].[tbl_LookupPlayerActionType] ([PlayerActionTypeId])
GO
ALTER TABLE [dbo].[tbl_PlayerActionLog] CHECK CONSTRAINT [FK_tbl_PlayerActionLog_tbl_LookupPlayerActionType]
GO
/****** Object: Index [tbl_PlayerActionLog_idx] Script Date: 14/8/2014 10:00:23 AM ******/
CREATE CLUSTERED INDEX [tbl_PlayerActionLog_idx] ON [dbo].[tbl_PlayerActionLog]
(
[LogYear] ASC,
[LogMonth] ASC,
[LogDay] ASC,
[LogTime] ASC,
[MerchantId] ASC,
[PlayerActionTypeId] 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
