SQL Import Data from Text File - Validate Each Client ID before insert

Posted on 2014-02-19
Last Modified: 2014-02-19
Hello Experts,

I have a tab delimited text file that I'll be using as a basis for periodic data import into my SQL 2005 database.  One of the fields in the text file is ClientID.  

What I need to do is loop through each row of the text file and determine whether the ClientID exists in our Clients table.  

If it does exist, it should go ahead and run a couple of different Insert queries in order to add specified fields from the text file row as a new record in certain tables.

If it does NOT exist, I need it to write out the entire row from the text file to an ImportError table.

I have all the code written for opening the text file and querying from it using some nice OPENROWSET code and I also have the Update queries written for both conditions (when ClientID is valid and when it is not valid).

What I Need is:

Guidance on how to best handle the initial step - check to see if the ClientID is valid in the Clients table and then direct the stored proc to carry out the appropriate update queries

I was thinking of the following plan:

Setting up a temporary table with 2 columns (ClientID as INT, Status as BIT)
Looping through the text file to find all distinct ClientIDs (can be more than 1 row with same ClientID)
Write out the ClientID and if valid, set status to 1, if not valid, set status to 0
Then, once the temp table is populated, use that as a To Do list of sorts and loop through each record using some sort of For Each or cursor functionality in order to read the status bit value of each row and either do the appropriate inserts (if 1) or write to error table (if 0).

I look forward to your creative ideas and appreciate your assistance!
Question by:dpmoney
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LVL 66

Expert Comment

by:Jim Horn
ID: 39871083
>What I need to do is loop through each row of the text file and determine whether the ClientID exists in our Clients table.  

Don't loop.  What you just described can all be handled in the T-SQL MERGE statement., other than it will execute only one statement for any given action instead of 'a couple'.

But if you tack on an OUTPUT clause at the end, it'll handle subsequent statements.
LVL 69

Accepted Solution

Scott Pletcher earned 500 total points
ID: 39871087
You need an UPDATE query for the main table, with an INNER JOIN, and an INSERT query for the ImportError table, with an OUTER JOIN.  [ixnay on the oopinglay!]

FROM dbo.main_table mt
    SELECT ...
) AS trans ON
    trans.ClientID = mt.ClientID

INSERT INTO dbo.importError
LEFT OUTER JOIN dbo.main_table mt ON
    mt.clientID = trans.clientID
    mt.ClientID IS NULL

Author Closing Comment

ID: 39871290
You are indeed a prodigy!  

I was able to take your example code and map it to my SQL without issue - works like a champ!  If I could give you bonus points for the pig Latin, I would.  

Thanks again!

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