SQl: Update Table from a text File

Question

Here's what I have to do :

I have a text file which has 3 columns: PID, X, Y.

Now I have two tables in my database:

• Table 1 contains 4 columns: UID, PID, X, Y
• Table 2 contains multiple columns, required ones being UID, X, Y

I need to update Table 2 with corresponding X and Y values.

I think we can use BULK INSERT for updating table 1, then some WHILE loop or something.

But I can't figure out exact thing.

Answer 1

CREATE PROCEDURE [dbo].[BulkInsert]            
(            
@PID int  ,          
@x int,          
@y int,          

)            
AS            
BEGIN            
SET NOCOUNT ON;            

declare @query varchar(max)            


CREATE TABLE #TEMP            
(            
[PID] [int] NOT NULL ,          
[x] int NOT NULL,          
[y] int NOT NULL,             

)            


SET @query = 'BULK INSERT #TEMP FROM ''' + PathOfYourTextFile + ''' WITH ( FIELDTERMINATOR = '','',ROWTERMINATOR = ''\n'')'            
--print @query            
--return            
execute(@query)            


BEGIN TRAN;            

MERGE TableName AS Target            
USING (SELECT * FROM #TEMP) AS Source            
ON (Target.YourTableId = Source.YourTextFileFieldId)
-- In the above line we are checking if the particular row exists in the table(Table1)  then update the Table1 if not then insert the new row in Table-1.           

WHEN MATCHED THEN            
UPDATE SET             
Target.PID= Source.PID, Target.x= Source.x, Target.y= Source.y           
WHEN NOT MATCHED BY TARGET THEN            

-- Insert statement  

You can use this above approach to solve your problem. Hope this helps. :)

Answer 2

How are you going to run it ? From a stored procedure ?

To save some performance, I would have done BULK INSERT to temp table, then insert from temp table to Table 1 & 2.

It should look like this

INSERT INTO Table1 ( PID, X, Y)
SELECT  PID, X, Y
FROM    #tempTable

Some will tell that temp table are not good, but it really depend - if you file is big, reading it from disk will take time and you don't want to do it twice.