I'm trying to Update a table but I keep getting the exception : Update unable to find TableMapping...
I even tried minimizing my code but I still don't see the problem
Items.cs
public static void WriteDescription()
{
DataSet items = DAL.GetDataSet("SELECT * FROM Items");
for (int i = 0; i < items.Tables[0].Rows.Count; i++)
items.Tables[0].Rows[i]["Description"] = "Hello";
DAL.UpdateDB("SELECT * FROM Items", items, "Items");
}
Dal.cs
static public void UpdateDB(string strSql, DataSet ds, string tablename)
{
SqlConnection connection = new SqlConnection(ConnectionString);
SqlCommand cmd = new SqlCommand(strSql, connection);
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
new SqlCommandBuilder(adapter);
adapter.Update(ds, tablename);
}
And I even tried removing the for, What could be the problem?
Based on how your code is designed, you should be using an SqlCommand object to perform the update without the SqlDataAdapter. The SqlDataAdapter is being used wrong, and it's unnecessary based on how your code is constructed.
The construction for the DataAdapter
SqlDataAdapter adapter = new
SqlDataAdapter(cmd);
sets the command (cmd) as the SELECT command for the DataAdapter, not the Update command. (A DataAdapter has an insert, update, delete, and select command)
Try this instead:
static public void UpdateDB(string strSql, DataSet ds, string tablename)
{
SqlConnection connection = new SqlConnection(ConnectionString);
SqlCommand cmd = new SqlCommand(strSql, connection);
try
{
connection.Open();
cmd.ExecuteNonQuery();
}
catch(Exception ex)
{
// error hanlding code here
}
finally
{
connection.Close();
}
}
Alternately, you could keep most of your code and set the update command properly - add a line that says
adapter.UpdateCommand = strSql;
just before the call to "Update".
Related
I am trying to run a test query using sql. I know it is a simple concept, but i have tried everything I could find online and the following does not even run. It shows no errors but it does not run.
private static SqlConnection conn = new SqlConnection("<connection string>");
public static void connect()
{
conn.Open();
SqlCommand command = new SqlCommand("spTester 'this is tested'", conn);
command.ExecuteScalar();
conn.Close();
}
It seems that you want something like that:
private static void connect() {
// static SqlConnection conn is a bad idea, local variable is much better
// Do not forget to dispose IDisposable: using(...) {...}
using (SqlConnection conn = new SqlConnection("<connection string>")) {
// Do not forget to dispose IDisposable: using(...) {...}
using (SqlCommand command = new SqlCommand("spTester", conn)) {
// You're executing procedure, not ordinal SQL
command.CommandType = CommandType.StoredProcedure;
// It seems, that you should provide a parameter to your procedure:
//TODO: Change "#ParameterName" to actual one
command.Parameters.Add(new SqlParameter("#ParameterName", "this is tested"));
// You don't need any result value be returned
command.ExecuteNonQuery();
}
}
}
public static void connect()
{
conn.Open();
SqlCommand command = new SqlCommand("spTester 'this is tested'", conn);
command.CommandType = CommandType.StoredProcedure;
SqlDataAdapter da = new SqlDataAdapter(cmd);
conn.Close();
}
try doing this..
as u probably forgot to mention command.CommandType = CommandType.StoredProcedure; line
this is a simple example it will let you get started using SQLCOMMAND
using (SqlConnection conn = new SqlConnection(connString))
{
SqlCommand cmd = new SqlCommand("SELECT * FROM whatever
WHERE id = 5", conn);
try
{
conn.Open();
newID = (int)cmd.ExecuteScalar();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
Try this :
public static void connect()
{
conn.Open();
SqlCommand command = new SqlCommand("spTester", conn);
command.CommandType = CommandType.StoredProcedure;
command.AddWithValue("#Parameter1","this is tested")
SqlDataAdapter da = new SqlDataAdapter(cmd);
conn.Close();
}
I want to get the result from a query in my oracle database and put it in a gridview. Now my problem is, I have no idea how to output it in the gridview. I am using the gridview from the toolbox and my oracle connection is working. I also have the right SELECT query and I can output that in a listbox. I just have no idea how to do this in a gridview. I looked for it and I came across this: How to populate gridview with mysql? Although this doesn't help me.
How can I output it in a gridview so that it looks exactly the same as a normal table in the oracle database?
What should I use and how?
This is my code:
public void read()
{
try
{
var conn = new OracleConnection("")
conn.Open();
OracleCommand cmd = new OracleCommand("select * from t1", conn);
OracleDataReader reader = cmd.ExecuteReader();
DataTable dataTable = new DataTable();
while (reader.Read())
{
var column1 = reader["vermogen"];
column = (column1.ToString());
listBox1.Items.Add(column);
}
conn.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
To bind a DataTable to a DataGridView your code need simply to be changed to
public void read()
{
try
{
using(OracleConnection conn = new OracleConnection("....."))
using(OracleCommand cmd = new OracleCommand("select * from t1", conn))
{
conn.Open();
using(OracleDataReader reader = cmd.ExecuteReader())
{
DataTable dataTable = new DataTable();
dataTable.Load(reader);
dataGridView1.DataSource = dataTable;
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
The OracleDataReader could be passed to the Load method of the DataTable and then the table is ready to be bound to the DataGridView DataSource property. I have also added some using statement to ensure proper disposing of the disposable objects employed. (In particular the OracleConnection is very expensive to not close in case of exceptions)
You can use DataSet too:
public void read()
{
try
{
OracleConnection conn = new OracleConnection("");
OracleCommand cmd = new OracleCommand("select * from t1", conn);
conn.Open();
cmd.CommandType = CommandType.Text;
DataSet ds = new DataSet();
OracleDataAdapter da = new OracleDataAdapter();
da.SelectCommand = cmd;
da.Fill(ds);
dataGridView1.DataSource = ds.Tables[0];
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
First establish connection in case, you didnt establish globally by using connection string. Then use oleDbcommand for the oracle sql command you want to execute. In my case, it is 'select * from table_name' which would show all data from table to datagrid. I wrote this code in a button to display data on data grid.
{
OleDbConnection conn = new OleDbConnection("");
OleDbCommand cmd = new OleDbCommand("select * from table_name", conn);
{
conn.Open();
OleDbDataReader reader = cmd.ExecuteReader();
{
DataTable dataTable = new DataTable();
dataTable.Load(reader);
dataGridView1.DataSource = dataTable;
}
conn.Close();
}
}
I have a desktop application project. In entry page a datagridview shows the existing items in database. Now when I entry new Item I want to insert it directly in datagridview. That mean I want to reload/refresh datagridview. My database is in MS Access.
private DataTable GetData()
{
DataTable dt = new DataTable();
//using (SqlConnection con = new SqlConnection(conn))
using (OleDbConnection con=new OleDbConnection(conn))
{
OleDbCommand cmd = new OleDbCommand("Select ID,Name from GroupDetails where comID='" + label1.Text + "'", con);
//SqlCommand cmd = new SqlCommand("Select ID,Name from GroupDetails where comID='" + label1.Text + "'", con);
con.Open();
//SqlDataAdapter ad = new SqlDataAdapter(cmd);
OleDbDataAdapter ad = new OleDbDataAdapter(cmd);
DataSet ds = new DataSet();
ad.Fill(ds);
dt = ds.Tables[0];
return dt;
}
}
private void btnSave_Click(object sender, EventArgs e)
{
//SqlConnection con = new SqlConnection(conn);
OleDbConnection con = new OleDbConnection(conn);
con.Open();
//SqlCommand cmd;
try
{
string query = "insert into GroupDetails (ID,Name) values(#ID,#Name)";
// cmd = new SqlCommand(query,con);
OleDbCommand cmd = new OleDbCommand(query, con);
cmd.Parameters.AddWithValue("#ID",txtID.Text);
cmd.Parameters.AddWithValue("#Name",txtName.Text);
int i = cmd.ExecuteNonQuery();
if(i!=0)
{
dataGridGroup.DataSource = GetData();
}
}
catch (Exception ex)
{
ex.Message.ToString();
}
finally
{
con.Close();
}
}
[Note: When I use sql database then it works fine.]
The dbDataAdapterClass (the one that OleDbDataAdapter inherits from) has a SelectCommand, UpdateCommand and InsertCommand. These are responsible for select, update, and insert when you explicit call any of the methods (for example update ;) ). Since in your code, you never provide the command that explain how to do the update, the dataadapter doesn't know how to do it.
so fulfill the requirements, adding an update command to the adapter.
dataadapter = new OleDbDataAdapter(sql, connection);
Add below code after above line, OleDbCommandBuilder will generate commands for you.
OleDbCommandBuilder cb = new OleDbCommandBuilder(dataadapter);
This tutorial should help you out.
I am trying to save a dataset to a database. I got a dataset from another class, Now changes will be made on the form by a user on a datagridview, then the changed Dataset needs to be saved in the database.
I am using the below code; Its not generating any errors, but the data is not being saved in the database.
public class myForm
{
DataSet myDataSet = new DataSet();
public void PouplateGridView()
{
try
{
SqlService sql = new SqlService(connectionString); // Valid Connection String, No Errors
myDataSet = sql.ExecuteSqlDataSet("SELECT * FROM Qualification"); // Returns a DataSet
myDataGridView.DataSource = myDataSet.Tables[0];
myDataGridView.AutoGenerateColumns = true;
myDataGridView.AutoResizeColumns();
}
catch (Exception ex)
{
MessageBox.Show(ex.InnerException + Environment.NewLine + ex.Message, "Error");
this.Close();
}
}
private void btnSave_Click(object sender, EventArgs e)
{
//myDataSet.AcceptChanges();EDIT:Don't know why, but this line wasn't letting the chane in db happen.
SqlCommand sc = new SqlCommand("SELECT * FROM Qualification", sql.Connection); //ADDED after Replies
SqlDataAdapter da = new SqlDataAdapter();
SqlCommandBuilder scb = new SqlCommandBuilder(da); //ADDED after replies
da.Update(myDataSet.Tables[0]);
}
}
public class mySqlService
{
public DataSet ExecuteSqlDataSet(string sql)
{
SqlCommand cmd = new SqlCommand();
this.Connect();
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
cmd.CommandTimeout = this.CommandTimeout;
cmd.Connection = _connection;
if (_transaction != null) cmd.Transaction = _transaction;
cmd.CommandText = sql;
cmd.CommandType = CommandType.Text;
da.SelectCommand = cmd;
da.Fill(ds);
da.Dispose();
cmd.Dispose();
if (this.AutoCloseConnection) this.Disconnect();
return ds;
}
}
What am I doing wrong here? There are ways on the web to save the dataset, if the datset is created, edited and saved in the same class etc., BUT I would like to have the select dataset method in the mySqlService class. How should I, now can save the dataset to the database?
EDIT:
I have commented the three lines that were required to make the code work. The code works now.
In order to run Update method of SqlDataAdapter you must have to configure InsertCommand, DeleteCommand and UpdateCommand properties along with SelectCommand of SqlDataAdapter or construct the SqlCommandBuilder object which configure these commands implicitly.
Hey try following this tutorial here http://support.microsoft.com/kb/308507 first and then adapt it to your needs.
I can't understand what I am doing wrong, I can't seem to SELECT with a prepared statement. However I can INSERT with a prepared statement.
MySqlCommand cmd = new MySqlCommand("SELECT * FROM code_post WHERE name = ?postRequired LIMIT 1", dbcon);
cmd.Parameters.Add(new MySqlParameter("?postRequired", requestString));
cmd.ExecuteNonQuery();
DataSet ds = new DataSet();
cmd.fill(ds, "result");
try {
thisBlog = ds.Tables["result"].Rows[0];
} catch {
invalid();
return;
}
Any advice on this would be greatly appreciated!
To fill a DataSet you will need a DataAdapter.
Try this:
MySqlCommand cmd = new MySqlCommand("SELECT * FROM code_post WHERE name = ?postRequired LIMIT 1", dbcon);
cmd.Parameters.Add(new MySqlParameter("?postRequired", requestString));
cmd.ExecuteNonQuery();
DataSet ds = new DataSet();
MySqlDataAdapter dAdap = new MySqlDataAdapter();
dAdap.SelectCommand = cmd;
dAdap.Fill(ds, "result");
try {
thisBlog = ds.Tables["result"].Rows[0];
} catch {
invalid();
return;
}
You need to use SqlDataAdapter
DataAdapter represents a set of data commands and a database connection that are used to fill the DataSet and update a SQL Server database.
The SqlDataAdapter provides this bridge by mapping Fill, which changes the data in the DataSet to match the data in the data source
Check the following syntax:
private static DataSet SelectRows(DataSet dataset,
string connectionString,string queryString)
{
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = new SqlCommand(
queryString, connection);
adapter.Fill(dataset);
return dataset;
}
}