CODEWITHSUNDEEP
c#sqlsql-server-2008
Kamran
Kamran

Reputation: 4100

How to set an integer value to one if a record exist in database C# Sql Query

getName_as_Rows is an array which contains some names.

I want to set an int value to 1 if record found in data base. 

for(int i = 0; i<100; i++)    
{

    using (var command = new SqlCommand("select some column from some table where column = @Value", con1))
    {
        command.Parameters.AddWithValue("@Value", getName_as_Rows[i]); 
        con1.Open();
        command.ExecuteNonQuery();
    }
}

I am looking for:

bool recordexist;

if the above record exist then bool = 1 else 0 with in the loop.

If have to do some other stuff if the record exist.

Upvotes: 0

Views: 366

Answers (2)

Max Rios
Max Rios

Reputation: 2256

To avoid making N queries to the database, something that could be very expensive in terms of processing, network and so worth, I suggest you to Join only once using a trick I learned. First you need a function in your database that splits a string into a table.

CREATE FUNCTION [DelimitedSplit8K]
--===== Define I/O parameters
        (@pString VARCHAR(8000), @pDelimiter CHAR(1))
RETURNS TABLE WITH SCHEMABINDING AS
 RETURN
--===== "Inline" CTE Driven "Tally Table" produces values from 0 up to 10,000...
     -- enough to cover VARCHAR(8000)
  WITH E1(N) AS (
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL 
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL 
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
                ),                          --10E+1 or 10 rows
       E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
       E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
 cteTally(N) AS (--==== This provides the "zero base" and limits the number of rows right up front
                     -- for both a performance gain and prevention of accidental "overruns"
                 SELECT 0 UNION ALL
                 SELECT TOP (DATALENGTH(ISNULL(@pString,1))) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
                ),
cteStart(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
                 SELECT t.N+1
                   FROM cteTally t
                  WHERE (SUBSTRING(@pString,t.N,1) = @pDelimiter OR t.N = 0) 
                )
--===== Do the actual split. The ISNULL/NULLIF combo handles the length for the final element when no delimiter is found.
 SELECT ItemNumber = ROW_NUMBER() OVER(ORDER BY s.N1),
        Item       = SUBSTRING(@pString,s.N1,ISNULL(NULLIF(CHARINDEX(@pDelimiter,@pString,s.N1),0)-s.N1,8000))
   FROM cteStart s
GO

Second, concatenate your 100 variables into 1 string:

"Value1", "Value 2", "Value 3"....

In Sql Server you can just join the values with your table

SELECT somecolumn FROM sometable t
INNER JOIN [DelimitedSplit8K](@DelimitedString, ',') v ON v.Item = t.somecolumn

So you find 100 strings at a time with only 1 query.

Upvotes: 1

Rob G
Rob G

Reputation: 3526

Use var result = command.ExecuteScalar() and check if result != null

But a better option than to loop would be to say use a select statement like

SELECT COUNT(*) FROM TABLE WHERE COLUMNVAL >= 0 AND COLUMNVAL < 100,

and run ExecuteScalar on that, and if the value is > 0, then set your variable to 1.

Upvotes: 0

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