Develop Reference

SqlDataAdapter handle error - object is not created

I have this error:
Invalid object name 'sap.AfdelingsrapportACTUAL'.
Which is because this table is not created yet.
I need to implement a check in my SqlDataAdapter - so if is null or doesnt get anything it moves on. But i really doesnt know how to.
I think it should be around my SqlDataAdapter but i could be wrong
Code
DataTable sqldt = new DataTable();
string sqlQuery = #"Select * from " + table;
SqlConnection sqlcon = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand(sqlQuery, sqlcon);
using (SqlDataAdapter da = new SqlDataAdapter(cmd))
{
da.Fill(sqldt);
}
What i think it should look like:
public static bool CompareDataTables(DataTable dt, string table, string connectionString)
{
DataTable sqldt = new DataTable();
string sqlQuery = #"Select * from " + table;
SqlConnection sqlcon = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand(sqlQuery, sqlcon);
using (SqlDataAdapter da = new SqlDataAdapter(cmd))
{
if (da == "doesnt have any table")
{
return true;
}
else
{
da.Fill(sqldt);
}
}
int sqlCols = sqldt.Columns.Count;
int excelCols = dt.Columns.Count;
if (excelCols == sqlCols)
{
return false;
}
else return true;
}

One way would be first check for the existence of the data table.
follow the sample given here:
Check if table exists in SQL Server

Trying to pass SqlCommand in SqlDataAdapter as parameters

I've successfully built up my method to execute a select command. It is working fine. Then I change my code for SqlDataAdapter DA = new SqlDataAdapter();
I tried to pass SqlCommand as CommandType.Text in the parameters but I can not do it successfully. I get error. Is there any way if I can pass it as parameters. Please see my code.
Running code (aspx page code)
if ((!string.IsNullOrEmpty(user_login.Value)) && (!string.IsNullOrEmpty(user_pass.Value)))
{
// username & password logic
DataTable dt = new DataTable();
string strQuery = "SELECT 1 FROM TBL_USER_INFO WHERE USERNAME = #USERNAME AND PASSWORD = #PASSWORD";
SqlCommand cmd = new SqlCommand(strQuery);
cmd.Parameters.Add("#USERNAME", SqlDbType.VarChar).Value = user_login.Value.Trim();
cmd.Parameters.Add("#PASSWORD", SqlDbType.VarChar).Value = user_pass.Value.Trim();
DBConnection conn_ = new DBConnection();
dt = conn_.SelectData(cmd);
if (conn_.SQL_dt.Rows.Count > 0)
{
Response.Redirect("Home.aspx", false);
}
}
Successful connection class code
public DataTable SelectData(SqlCommand command)
{
try
{
conn.Open();
SqlDataAdapter DA = new SqlDataAdapter();
command.CommandType = CommandType.Text;
command.Connection = conn;
DA.SelectCommand = command;
DA.Fill(SQL_dt);
return SQL_dt;
}
catch (Exception ex)
{
return null;
}
finally
{
conn.Close();
}
}
How can I pass CommandType.Text as parameters for SqlDataAdapter?
Error code
public DataTable SelectData(SqlCommand command)
{
try
{
conn.Open();
SqlDataAdapter DA = new SqlDataAdapter(command.CommandType.ToString(), conn);
// command.CommandType = CommandType.Text;
// command.Connection = conn;
DA.SelectCommand = command;
DA.Fill(SQL_dt);
return SQL_dt;
}
catch (Exception ex)
{
return null;
}
finally
{
conn.Close();
}
}
I am getting this error:
System.InvalidOperationException: Fill: SelectCommand.Connection property has not been initialized.
at System.Data.Common.DbDataAdapter.GetConnection3(DbDataAdapter adapter, IDbCommand command, String method)...

public DataTable SelectData(string query)
{
DataTable dt = new DataTable();
using (SqlConnection con = new SqlConnection("Your Connection String here"))
{
con.Open();
using (SqlCommand cmd = con.CreateCommand())
{
cmd.CommandText = query;
cmd.CommandType = CommandType.Text;
using (SqlDataAdapter adp = new SqlDataAdapter(cmd))
{
adp.Fill(dt);
return dt;
}
}
}
}
To use:
SelectData("select * from yourTable");

Reds has the answer. Just to clean the code up a little bit...
public DataTable SelectData(string query)
{
using (var connection = new SqlConnection("myConnectionString"))
using (var command = new SqlCommand(query, connection))
using (var adapter = new SqlDataAdapter(command))
{
var dt = new DataTable();
connection.Open();
adapter.Fill(dt);
return dt;
}
}

Actually you should pass the connection object on SQLCommand.Hope it helped you
DBConnection conn_ = new DBConnection();
SqlCommand cmd = new SqlCommand(strQuery,conn_);

The error that you are getting is not related to CommandType.Text, it says you have initialised the connection property of of SelectCommand. Basically you should uncomment "command.Connection = conn;" to get rid of this error. If you still face any other issue , it is better to provide those details in the questions to provide accurate answer.

How to select all fields but show certain in DataGridView in C#

I am showing some data on DataGridView in c# windows form App. Here I want to select ID because I have to use it as foreign key but I don't want to show that ID field on grid.
using (SqlConnection con = new SqlConnection(constr))
{
con.Open();
using (SqlCommand command = new SqlCommand("select * from PatientInfo", con))
{
SqlDataReader reader = command.ExecuteReader();
if (reader.HasRows)
{
DataTable dt = new DataTable();
dt.Load(reader);
datagridpatient.DataSource = dt;
con.Close();
}
}
}
I want to show just name, email, phone. At the same time for further use I need to select ID too.

you can hide the column,
dataGridView.Columns["ColumnName"].Visible = false;
Ex:
using (SqlConnection con = new SqlConnection(constr))
{
if (con.State == ConnectionState.Closed)
{
con.Open();
using (SqlCommand command = new SqlCommand("select * from PatientInfo", con))
{
SqlDataReader reader = command.ExecuteReader();
if (reader.HasRows)
{
DataTable dt = new DataTable();
dt.Load(reader);
datagridpatient.DataSource = dt;
if (datagridpatient.Columns.Contains("ID")
datagridpatient.Columns["ID"].Visible = false;
con.Close();
}
}
}
}

Why Datatables return Null when it is executed via SQL Command text?

I got two classes, one for db connection and another to get data. When I use the SqlCommand type as stored procedure it returns the data table properly, but when I change the command type to text and change the command text properly it returns a null value. Why is this happening?
Class 1
public class DB_Connection
{
public SqlConnection cnn;
public SqlCommand cmd;
public SqlDataAdapter ada;
public DB_Connection()
{
cnn = new SqlConnection("Data Source=svr01;Initial Catalog=PDFScramble;Integrated Security=True");
cnn.Open();
cmd = new SqlCommand();
cmd.CommandType = CommandType.Text;// *changed in here SP or Text*
cmd.Connection = cnn;
ada = new SqlDataAdapter();
ada.SelectCommand = cmd;
}
Class 2
public class Data : DB_Connection
{
public string DException { get; set; }
public DataTable Datatable { get; set; }
public bool GetCivicEntities()
{
try
{
cmd.CommandText = "SELECT Id, Description, StateId ,EntityTypeId FROM CivicEntities";
ada.Fill(Datatable);// *Null in here*
return true;
}
catch (Exception ex)
{
DException = ex.Message;
return false;
}
}

Your Datatable is null, because of that you have this problem. This should fix it.
cmd.CommandText = "SELECT Id, Description, StateId ,EntityTypeId FROM CivicEntities";
Datatable = new DataTable();
ada.Fill(Datatable);
return true;

There is something wrong with the class structure. Check with this
using (SqlConnection conn = new SqlConnection("connectionString"))
{
SqlCommand cmd = null;
SqlParameter prm = null;
SqlDataAdapter dad = null;
DataTable dt = new DataTable();
cmd = new SqlCommand("SPName", conn);
cmd.CommandType = CommandType.StoredProcedure;
conn.Open();
dad = new SqlDataAdapter(cmd);
dad.Fill(dt);
conn.Close();
}
using (SqlConnection conn = new SqlConnection("connectionString"))
{
SqlCommand cmd = null;
SqlParameter prm = null;
SqlDataAdapter dad = null;
DataTable dt = new DataTable();
cmd = new SqlCommand("select * from dummy",conn);
cmd.CommandType = CommandType.StoredProcedure;
conn.Open();
dad = new SqlDataAdapter(cmd);
dad.Fill(dt);
conn.Close();
}

How to insert results from one database to another in c# application

How can you connect the result of a query from one database and insert it into another in a c# application?
This is what I have so far but it doesnt work.
// select from first database
string sCMD_All = "SELECT * FROM table";
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
using (SqlConnection myConn = new SqlConnection(ConnectionString))
{
using (SqlCommand myCommand = new SqlCommand(sCMD_All, myConn))
{
myConn.Open();
SqlDataReader reader = myCommand.ExecuteReader();
da.Fill(ds);
myConn.Close();
}
}
DataTable sqTable = ds.Tables[0];
//insert into 2nd database
DataTable newTable = new DataTable();
newTable = sqTable;
using (SqlConnection myConn = new SqlConnection(ConnectionString_M))
{
string sCMD_I = "INSERT INTO tableNew #newTable";
using (SqlCommand myCommand = new SqlCommand(sCMD_I, myConn))
{
myConn.Open();
SqlDataReader reader = myCommand.ExecuteReader();
myConn.Close();
}
}

var commandText =
#"insert into [server].[database2].[schema].[table] (col1, col2, ...)
select col1, col2, ... from [server].[database1].[schema].[table]";
using (var connection = new SqlConnection(connectionString))
{
using (var command = new SqlCommand(commandText, connection))
{
connection.Open();
command.ExecuteNonQuery();
}
}
NOTE: If databases are located on different servers, you should link servers:
exec sp_addlinkedserver #server = 'server2'