Can somme one explaine me this " if (dt.row [0][0].tostring () == "this"){ console.write ("this")}

Question

explanation

Answer 1

if //just an if statement
dt.row //datatable row
dt.row[0][0] //first [0] is row index //second [0] is cel index
.tostring() //get the string value of dt.row[0][0]
== // is equal to
"this" // the string "this", in this case it is not the object

console.write("this") //write this to console.

So if the first cel of the first row of the datatable contains the text "this", the program wil print the text "this" to the console.

Answer 2

For the backup part I would use a simple File copy

After that use
use a 2 SqlConnection to connect to the two databases
use a 2 SqlCommand to define your request "select * from tableX"
and a 2 SqlDataReader to read the data

Compare the value and set values if needed.

https://www.sololearn.com/Discuss/471763/how-to-use-database-in-c-application

Answer 3

yes yes that is it. thank you very Much i now understand the situation

Answer 4

Yes it is possible and there are different ways to do it.

What is you definition of backup ?
Just store raw data so you can restore it later
Or
in SQL terms create a .bak file
(not sure if Access is able to do that ?)

What do you want to achieve ?

Answer 5

So you need a backup in a file ?
(sorry for asking again but I need to understand it)
Is it really neccesary to split the database ?

What if you can compare and update the five tables
without affecting the other six

Would that be sufficient ?

Answer 6

A connection to a database

// Northwind.mdb is located in the c:\Data folder.
string connectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source="
+ "c:\\Data\\Northwind.mdb;User Id=admin;Password=;";
Link :
https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/ado-net-code-examples#oledb

Get all rows (just from one table)
string constr = @"Data Source=.;Initial Catalog=test;Integrated Security=True";
SqlConnection con = new SqlConnection(constr);
con.Open();
SqlDataAdapter adpt = new SqlDataAdapter("select * from Items",con);
DataTable dt = new DataTable();
adpt.Fill(dt);

link : https://www.codeproject.com/Questions/353481/How-can-we-fill-data-table-in-sqlcommand

Modify the row
foreach(DataRow dr in table.Rows) // search whole table
{
if(dr["Product_id"] == 2) // if id==2
{
dr["Product_name"] = "cde"; //change the name
//break; break or not depending on you
}
}

Link : https://stackoverflow.com/questions/19629644/how-to-edit-a-row-in-the-datatable

If you only load the table you need to validate and modify the row that need to be changed, the other 5 a be left unchanged.

Answer 7

sneeze please i have another question please.
" do you think it is possible to backup 5 tables in your acess database, clear it, and later restore it. that is the logic. Is it possible?

Answer 8

To access a database in c# there are 3 methods.

1) microsoft.interop
2) sql, sql-connection and sql command and sql reader
3) datatable and data-adapter object
4) file copy the database mdb-file

Answer 9

yes i want to store complet table all columns and rows with their values and give a a name to the save table as "saved table " and then clear the present table. And be able to restore it any time when needed. The real situation is that; i want to compare two table. For example create a form that compare two datatable e.g "table 2017 & table 2018 "

Answer 10

ok sneeze. But file copy system copy the database or table. because i saw a tutorial where it copy the database with all the tables inside the database. but i just needed To saved a few 5 tables out of 11 tables without affecting the other 6 tables.

Answer 11

Just brainstorming with you.

You already have a datatable do you ?
Is the datatable appropriate storage for you or do you need the backup in file format ?

Answer 12

yes i have a datatable. i need a backup format.

Answer 13

yes that is better for me sneeze.

Answer 14

As you said, without affecting the other tables.

Answer 15

Thank you, I understand it now. Come back to you later

Answer 16

Ok thanks.