Question

I’ve merged a three tables into one table and I’ve noticed that each merged table has similar data columns producing redundancy.

What is the best way to update all of these columns into one column?

Right now the data will read

WallJambHeadCut | WallJambSillCut | DoorJambSillCut | DoorJambHeadCut | ect ....
       1               0                0                   0 
       0               0                1                   0

The above needs to be condensed down too two columns:

  Headcut | SillCut

In other words each one of these columns can be condensed into one. I just want to make sure that I write the correct update statement because I would hate the jack my data up.

CREATE TABLE [dbo].[Table_1](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [WallJambHeadCut] [bit] NOT NULL,
    [WallJambSillCut] [bit] NOT NULL,
    [DoorJambSillCut] [bit] NOT NULL,
    [DoorJambHeadCut] [bit] NOT NULL,
    [VerticalHeadCut] [bit] NOT NULL,
    [VerticalSillCut] [bit] NOT NULL,
 CONSTRAINT [PK_Table_1] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

Answer 1

Depending on the complexity you want to do, you can replace all the columns with a column of type tinyint and do bitwise operations to handle the data. We actually do that in the project I’m working on.

For the example you gave, you will have

0000 1000  --Which is 8
0000 0010  --Which is 2

Whenever you need to update these values you just use the operators.

You can check more information here http://msdn.microsoft.com/en-us/library/ms176122.aspx

The tinyint is better because it only occupies 8 bits

1. Add the new column
2. update the table and set newCol = WallJambHeadCut | WallJambSillCut | DoorJambSillCut | DoorJambHeadCut –For each row

Cheers