How could I check if import this text file into DB or not ?

Question

Hello everyone . I have wrote a code which is reading Text Files and save them in a list after that import this list into DB so far it's fine the problem is i have until now 400 text fiels each text fiel has around 300000 until 500000 line and each time want to import a new text flel it will reinsert or reimport the text files which are already imported . that's meaing my data will be always duplicated. so how could i check with C# code if this text files is already imported or exist in DB ?! here is some code to be more clear : private static List GetWebShopDataAccesses( string path) { List elements = new List List string > lines = File.ReadAllLines(path).ToList(); return elements; // here i am gettng the list back then import this list into DB during an extensions method with sqlbulk } private static void ImportToDB() { string CS = "" using (SqlConnection connection = new SqlConnection(CS)) { SqlBulkCopy bulkCopy = new SqlBulkCopy(connection, SqlBulkCopyOptions.TableLock | SqlBulkCopyOptions.FireTriggers | SqlBulkCopyOptions.UseInternalTransaction, null ); bulkCopy.DestinationTableName = "TestWebShop" ; connection.Open(); bulkCopy.WriteToServer(GetListOfWebShop.AsDataTable()); } }

Rajanikant Hawaldar · Answer

https://forums.asp.net/t/1880640.aspx?Prevent+Duplicate+entries+in+SQL+Bulk+Copy

Laxmidhar Sahoo · Answer

@Ranjanikant Thanks .

Laxmidhar Sahoo · Answer

hey You define List elements = new List Where assign the value to element. Another thing the bellow is the table for bulluck insert protected void Bulk_Insert( object sender, EventArgs e) { DataTable dt = new DataTable(); dt.Columns.AddRange({ new DataColumn( "contain" , typeof ( string ), }); foreach (var line in lines) { string contain = line; dt.Rows.Add(contain); } if (dt.Rows.Count > 0) { string consString = ConfigurationManager.ConnectionStrings[ "constr" ].ConnectionString; using (SqlConnection con = new SqlConnection(consString)) { using (SqlBulkCopy sqlBulkCopy = new SqlBulkCopy(con)) { //Set the database table name sqlBulkCopy.DestinationTableName = "dbo.Customers" ; //[OPTIONAL]: Map the DataTable columns with that of the database table sqlBulkCopy.ColumnMappings.Add( "contain" , "contain" ); con.Open(); sqlBulkCopy.WriteToServer(dt); con.Close(); } } } }