problem realated to database

try this code

qry = "select * from department_master where dep_code='" + txt.Text + "'";
sql_cmd = new SqlCommand(qry, sql_con);
sql_con.Open();
sql_rs = sql_cmd.ExecuteReader();
if (sql_rs.Read())
{
    //exists
}
else
{
    //not exists
}
sql_rs.Close();
sql_con.Close();

Hai
First u have use select data from database and fill into data table,and check row count,if it is above 1 then database have row,use where condition for select query then only u find exact data exit or not.
for examble

OleDbConnection cn;
OleDbCommand cmd2;
cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" your dbpath herer ";Jet OLEDB:");
cn.Open();
OleDbDataAdapter objDA = new OleDbDataAdapter("select * from Users where UserId='007'", cn);
DataTable objDT = new DataTable();
objDA.Fill(objDT);
if ((objDT.Rows.Count == 1)) {
    // database have row
}

the above code for select exact data from table,here users is table,but u want database have data or not
try like this

OleDbConnection cn;
OleDbCommand cmd2;
cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" your dbpath herer ";Jet OLEDB:");
cn.Open();
OleDbDataAdapter objDA = new OleDbDataAdapter("select * from Users", cn);
DataTable objDT = new DataTable();
objDA.Fill(objDT);
if ((objDT.Rows.Count == 1)) {
    // database have row
}

Regards
Aravind