compare csv records in database and add new line

6y867Learn iOS Programming

Hi, wanna ask, how to compare CSV from CSV file and database? I using lastwritetime to see changes in CSV. If lastwritetime same, it means there are no new records in the CSV file. If lastwritetime got changes, it means there are new records added in CSV file and I want to add it to database without duplicate the records. Means only insert the new records into database. Help me please.

var lwt = "select COUNT(*) from listfile where lastwritetime=@lastwritetime";
var cmd2 = new NpgsqlCommand(lwt, conn);
cmd2.Parameters.AddWithValue("lastwritetime", Convert.ToDateTime(lastWriteTime));
int LWT = Convert.ToInt32(cmd.ExecuteScalar());
cmd2.ExecuteNonQuery();
if (LWT > 0)
{
Console.WriteLine("There are no changes in lastWriteTime CSV file");
}
else
{
Console.WriteLine("There are changes lastWriteTime in CSV file");
var lf2 = "insert into listfile(filename,lastwritetime)values(@filename,@lastwritetime)";
var cmd3 = new NpgsqlCommand(lf2, conn);
cmd3.Parameters.AddWithValue("filename", Convert.ToString(file));
string filename = cmd3.Parameters["@filename"].Value.ToString();
Console.WriteLine("Record inserted successfully. filename = " + file);
cmd3.Parameters.AddWithValue("lastWriteTime", Convert.ToDateTime(lastWriteTime));
string time = cmd3.Parameters["@lastwritetime"].Value.ToString();
Console.WriteLine("Record inserted successfully. lastWriteTime = " + lastWriteTime);
cmd3.ExecuteNonQuery();
}

3 Replies

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Nisha Regil6y ago
Yes, in column1=@column1

column1 refers to table column and @column1 refers to value of csv column for comparing if value exists.

You have to keep on adding column comparison for all the columns in table and csv.
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6y ago
Yes i have the table, result table. So the command is like this? Select count(1) from result where column1=@column1
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Nisha Regil6y ago
Is there any database table into which you are inserting the records from CSV?

If yes, Is there any way to identify values in table uniquely which is also unique to CSV file.

At line #14 you need introduce code to check if there are columns matching in csv and database table.
for that first you need to read all data from csv. Loop though it and check for same values in table.
eg. select count(1) from tablename where column1 = @column1.

If value of count more than 1 then don't insert else insert.
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