Rafael Adel Rafael Adel - 5 months ago 26
SQL Question

Must declare the table variable @table

I'm a beginner in C# and SQL, i have this SQL insert statement that i want to perform. It asks for the table name among the other variables that i want to insert.

But when i run this console app i get this error :


Must declare the table variable @table


This is a part of the code :

StreamReader my_reader = getFile(args);
string CS = formCS();
try
{
using (SqlConnection con = new SqlConnection(CS))
{
SqlCommand com = new SqlCommand("insert into @table (time, date, pin) values (@time, @date, @pin)", con);
con.Open();
Console.WriteLine("Enter table name:");
Console.Write(">> ");
string tblname = Console.ReadLine();
com.Parameters.AddWithValue("@table", tblname);

string line = "";
int count = 0;
while ((line = my_reader.ReadLine()) != null)
{
Dictionary<string, string> result = extractData(line);
com.Parameters.AddWithValue("@time", result["regTime"]);
com.Parameters.AddWithValue("@date", result["regDate"]);
com.Parameters.AddWithValue("@pin", result["regPin"]);
count += com.ExecuteNonQuery();
com.Parameters.Clear();

}
Console.WriteLine("Recoreds added : {0}", count.ToString());
Console.WriteLine("Press Enter to exit.");
}
Console.ReadLine();
}
catch (SqlException ex)
{
Console.WriteLine(ex.Message);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}

Answer

You can't do this. You can't pass the table name as a parameter the way you did:

SqlCommand com = new SqlCommand("insert into @table ...");
...
com.Parameters.AddWithValue("@table", tblname);

You can do this instead:

Console.WriteLine("Enter table name:");
Console.Write(">> ");
string tblname = Console.ReadLine();

string sql = String.Format("insert into {0} (time, date, pin) values ... ", tblname);

SqlCommand com = new SqlCommand(sql, con);                    

...
Comments