Ok, I have been having a problem the last few days with my database not updating. I can read the data fine and I'm not getting any exceptions either. I'm trying to update the database then I try to read values again after the update (during same run), and they still hold the original values, so it doesn't seem to be an issue with the database being copied to another folder (I'm using Copy if newer yet neither database is being updated).
Here is the code I'm using. As you can see I tried a few different approaches, none of which worked yet.
public void UpdateDatabaseInStock(string itemName, string tableName)
{
DataSet data = new DataSet("Items");
int val;
//get the file path to the database as a string
string dbfile =
new System.IO.FileInfo(System.Reflection.Assembly.GetExecutingAssembly().Location).DirectoryName +
"\\Database\\GameData.sdf";
//connect to the database
using (SqlCeConnection cntn = new SqlCeConnection("datasource=" + dbfile))
{
//create an adapter to pull all data from the table
using (SqlCeDataAdapter adpt = new SqlCeDataAdapter
("SELECT * FROM " + tableName + " WHERE Name LIKE '%" + itemName + "%'", cntn))
{
//put the data into a DataSet
adpt.Fill(data);
cntn.Close();
}
//fill the data from the Items table into a DataTable to return.
DataTable itemTable = data.Tables[0];
DataRow a = itemTable.Rows[0];
val = (short)a.ItemArray[3] - 1;
dbfile = "";
data.Dispose();
itemTable.Dispose();
SqlCeCommand cmd = new SqlCeCommand();
cmd.Connection = cntn;
cntn.Open();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "UPDATE " + tableName + " SET [In Stock] = #Value WHERE [Name] = '#ItemName'";
//cmd.Parameters.Add("#Value", SqlDbType.SmallInt);
//cmd.Parameters["#Value"].Value = val;
//cmd.Parameters.Add("#ItemName", SqlDbType.NChar, 75);
//cmd.Parameters["#ItemName"].Value = itemName;
cmd.Parameters.AddWithValue("#Value", val);
cmd.Parameters.AddWithValue("#ItemName", itemName);
cmd.ExecuteNonQuery();
//close the conenction
cntn.Close();
cmd.Dispose();
}
}
Any ideas to get it to actually update?
Just a hunch (can't corroborate this on msdn): could it be that using nchar(75) adds spaces to the parameter, thereby causing the WHERE clause to fail?
Related
I created a C# application to query and insert a product database. However I am here with a small doubt and if anyone can help me i thank you right away.
The following is:
I have a form to insert data into the database created in MS Access 2007, with the values of reference, sale number, client code, client name, quantity and position number in archive;
Here is my code until the moment:
private void btn_save_Click(object sender, EventArgs e)
{
OleDbConnection con = new OleDbConnection(#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=product.accdb");
OleDbCommand check_sn = new OleDbCommand("SELECT COUNT(*) FROM [product] WHERE ([sn] = #sn)", con);
OleDbCommand check_reference = new OleDbCommand("SELECT COUNT(*) FROM [product] WHERE ([reference] = #ref)", con);
OleDbCommand check_number = new OleDbCommand("SELECT COUNT(*) FROM [product] WHERE ([number] = #num)", con);
con.Open();
check_reference.Parameters.AddWithValue("#ref", textBox_ref.Text);
check_sn.Parameters.AddWithValue("#sn", textBox_sn.Text);
check_number.Parameters.AddWithValue("#num", textBox_num.Text);
int refExist = (int)check_reference.ExecuteScalar();
int SNExist = (int)check_sn.ExecuteScalar();
int numExist = (int)check_number.ExecuteScalar();
if (refExist > 0)
{
MessageBox.Show("A product with this reference already exists....!");
}
else if (SNExist> 0)
{
MessageBox.Show("A product with this sale number already exists....!");
}
else if (numExist > 0)
{
MessageBox.Show("A product with this archive number already exists....!");
}
else
{
try
{
String reference = textBox_ref.Text.ToString();
String sn = textBox_ov.Text.ToString();
String cod_client = textBox_cod.Text.ToString();
String client = textBox_cliente.Text.ToString();
String qtd = textBox_qtd.Text.ToString();
String number = textBox_num.Text.ToString(); //This will be the incremented number
String my_query = "INSERT INTO product(reference,sn,cod_client,client,qtd,number)VALUES('" + reference + "','" + sn + "','" + cod_client + "','" + client + "','" + qtd + "','" + number + "')";
OleDbCommand cmd = new OleDbCommand(my_query, con);
cmd.ExecuteNonQuery();
MessageBox.Show("Data saved successfully...!");
}
catch (Exception ex)
{
MessageBox.Show("Failed due to" + ex.Message);
}
finally
{
con.Close();
}
cleanTextBoxes(this.Controls);
}
}
private void search_btn_Click(object sender, EventArgs e)
{
Form search = new Form_search();
search.Show();
this.Hide();
}
}
}
How can i make it so that instead of manually entering the position number in archive in the textbox it can be automatically filled with the new position in archive. For example, my last product inserted has the position 50 in archive, the new one will automatically be number 51 and so on ... and this number should appear automatically in the textbox so that the user knows what is the number of the new registered product.
Thank you,
Ok i have tried this and works but how i do now to increment this value +1?
OleDbConnection con = new OleDbConnection(#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=Aneis_Calibre.accdb");
con.Open();
OleDbDataReader myReader = null;
OleDbCommand number = new OleDbCommand("SELECT TOP 1 [number] FROM product Order by [number] desc", con);
myReader = number.ExecuteReader();
while (myReader.Read())
{
textBox_num.Text = (myReader["number"].ToString());
}
con.Close();
Inside your query, you would want to do something along these lines.
INSERT ...
OUTPUT inserted.identity_column
VALUES (...)
That will return a row with a value for the id. The identity column in SQL will always increment automatically for you. Which would alleviate your approach where you grab the last record and do:
int.TryParse(reader["..."]?.ToString(), out int id);
textbox.Text = id++;
By using the scalar, or reader though I would recommend scalar if you return a single column with a modified SQL query would result in the exact newly inserted id.
I have to update multiple records in SQL Server table from C#. Below are the steps I have to follow and below is the code.
The code is working but the process is taking much longer than expected.
I need a quick way to update 10000 records, not sure whether Bulk Copy would work for Update.
I have seen the other answers which has Bulk insert to temp and then update..But that update has a single statement and here I need to update the records in DB based on Excel data and for this I have to loop each excel record.So how can I achieve faster update.
1) Read the Excel Data and copied the data into a data table
string strDirectory = string. Empty;
strDirectory = System.IO.Directory.GetCurrentDirectory() + "\\" + "Filename.xlsx";
string Connection String = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source = " + strDirectory + "; Extended Properties = \"Excel 12.0;HDR=YES;IMEX=1\"";
using (OleDbConnection conn = new OleDbConnection(Connection String))
{
conn.Open();
DataTable schemaTable = conn.GetOleDbSchemaTableOleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
DataRow schemaRow = schemaTable. Rows[0];
string sheet = schemaRow["TABLE_NAME"].ToString();
string query = "SELECT * FROM [" + sheet + "]";
OleDbDataAdapter daexcel = new OleDbDataAdapter(query, conn);
daexcel.Fill(dt);
conn.Close();
}
2) Doing some manipulations on datatable data before updating into table.
string strsqlst = string. Empty;
using (SqlConnection sqlConn = new SqlConnection(Connectionstring))
{
sqlConn.Open();
SqlCommand cmd;
StringBuilder sb = new StringBuilder();
sb.AppendLine("DataTable content:");
foreach (DataRow row in dt.Rows)
{
if (row.ItemArray[0].ToString() == "")
break;
strsqlst = "Update table Set col1= " + row.ItemArray[4].ToString() + " ,col2= " + row.ItemArray[5].ToString() + " where <Condition>'";
cmd = new SqlCommand(strsqlst, sqlConn);
cmd.CommandType = CommandType.Text;
cmd.ExecuteNonQuery();
}
sqlConn.Close();
}
The SqlCommand can be a whole SQL batch and is not limited to a single statement. So you can create a single large batch with 10,000 UPDATE statements, or divide it into for example 20 batches of 500 each.
In other words, you can create a single command with CommandText like this:
UPDATE [T] SET Col1='Value1', Col2='Value2' WHERE [Id] = 1;
...
UPDATE [T] SET Col1='Value999', Col2='Value1000' WHERE [Id] = 500;
That said, you should use parameters for all data values (to ensure SQL injection is not possible).
If you want to handle any errors (updates failing due to invalid data) you will need something a bit more sophisticated.
Is there anything wrong with my code? It is not showing data in textboxes. The same funtion is working for another table in database but not for this one.
private void metroButton1_Click(object sender, EventArgs e)
{
con = new SqlConnection(constr);
String query = "Select FROM Student WHERE Std_ID = '" + metroTextBox1.Text + "'";
cmd = new SqlCommand(query, con);
con.Open();
try
{
using (SqlDataReader read = cmd.ExecuteReader())
{
while (read.Read())
{
// metroTextBox1.Text = (read["ID"].ToString());
metroTextBox2.Text = (read["Name"].ToString());
metroTextBox3.Text = (read["F_Name"].ToString());
metroTextBox4.Text = (read["Std_Age"].ToString());
metroTextBox5.Text = (read["Address"].ToString());
metroTextBox6.Text = (read["Program"].ToString());
metroComboBox1.Text = (read["Course"].ToString());
}
}
}
finally
{
con.Close();
}
}
you need to give column names in the select statement or select *
for example :
String query = "Select * from Student WHERE Std_ID = '" + metroTextBox1.Text + "'";
Not related to Question: you can change the while loop to if condition if you have one record for given id. even there are many records for given id you will see the last record data only because of the while loop will overwrite the textboxes in every record.
Update :
There isn't anything wrong with Syntax because the same syntax is
working for modifying teacher funtion.
No, this is incorrect, remove the try catch in your code then you will see the exception of syntax error
I have filled a DataSet with a Table that was created from another database file. The table is NOT in the database file which I want to be able to copy the Table to.
Now I want to save all those records (DataTable) to a newly created SQLite database file...
How can i do that?
Also I really want to avoid loops if this is possible.
The best answer is by me :) so i'll share it.This is loop but writes 100k entries in 2-3secs.
using (DbTransaction dbTrans = kaupykliuduomConn.BeginTransaction())
{
downloadas.Visible = true; //my progressbar
downloadas.Maximum = dataSet1.Tables["duomenys"].Rows.Count;
using (DbCommand cmd = kaupykliuduomConn.CreateCommand())
{
cmd.CommandText = "INSERT INTO duomenys(Barkodas, Preke, kiekis) VALUES(?,?,?)";
DbParameter Field1 = cmd.CreateParameter();
DbParameter Field2 = cmd.CreateParameter();
DbParameter Field3 = cmd.CreateParameter();
cmd.Parameters.Add(Field1);
cmd.Parameters.Add(Field2);
cmd.Parameters.Add(Field3);
while (n != dataSet1.Tables["duomenys"].Rows.Count)
{
Field1.Value = dataSet1.Tables["duomenys"].Rows[n]["Barkodas"].ToString();
Field2.Value = dataSet1.Tables["duomenys"].Rows[n]["Preke"].ToString();
Field3.Value = dataSet1.Tables["duomenys"].Rows[n]["kiekis"].ToString();
downloadas.Value = n;
n++;
cmd.ExecuteNonQuery();
}
}
dbTrans.Commit();
}
In this case dataSet1.Tables["duomenys"] is already filled with all the data i need to transfer to another database. I used loop to fill dataset too.
When you load the DataTable from the source database, set the AcceptChangesDuringFill property of the data adapter to false, so that loaded records are kept in the Added state (assuming that the source database is SQL Server)
var sqlAdapter = new SqlDataAdapter("SELECT * FROM the_table", sqlConnection);
DataTable table = new DataTable();
sqlAdapter.AcceptChangesDuringFill = false;
sqlAdapter.Fill(table);
Create the table in the SQLite database, by executing the CREATE TABLE statement directly with SQLiteCommand.ExecuteNonQuery
Create a new DataAdapter for the SQLite database connection, and use it to Update the db:
var sqliteAdapter = new SQLiteDataAdapter("SELECT * FROM the_table", sqliteConnection);
var cmdBuilder = new SQLiteCommandBuilder(sqliteAdapter);
sqliteAdapter.Update(table);
If the source and target tables have the same column names and compatible types, it should work fine...
The way to import SQL data to SQLite will take long time. When you want to import data in millions, It will take lot of time. So the shortest and easiest way to do that is just fill fetch the data from SQL database in a DataTable and insert all its rows to SQLite database.
public bool ImportDataToSQLiteDatabase(string Proc, string SQLiteDatabase, params object[] obj)
{
DataTable result = null;
SqlConnection conn = null;
SqlCommand cmd = null;
try
{
result = new DataTable();
using (conn = new SqlConnection(ConStr))
{
using (cmd = CreateCommand(Proc, CommandType.StoredProcedure, obj))
{
cmd.Connection = conn;
conn.Open();
result.Load(cmd.ExecuteReader());
}
}
using (SQLiteConnection con = new SQLiteConnection(string.Format("Data Source={0};Version=3;New=False;Compress=True;Max Pool Size=100;", SQLiteDatabase)))
{
con.Open();
using (SQLiteTransaction transaction = con.BeginTransaction())
{
foreach (DataRow row in result.Rows)
{
using (SQLiteCommand sqlitecommand = new SQLiteCommand("insert into table(fh,ch,mt,pn) values ('" + Convert.ToString(row[0]) + "','" + Convert.ToString(row[1]) + "','"
+ Convert.ToString(row[2]) + "','" + Convert.ToString(row[3]) + "')", con))
{
sqlitecommand.ExecuteNonQuery();
}
}
transaction.Commit();
new General().WriteApplicationLog("Data successfully imported.");
return true;
}
}
}
catch (Exception ex)
{
result = null;
return false;
}
finally
{
if (conn.State == ConnectionState.Open)
conn.Close();
}
}
It will take a very few time as compare to upper given answers.
I have a C# webservice on a Windows Server that I am interfacing with on a linux server with PHP. The PHP grabs information from the database and then the page offers a "more information" button which then calls the webservice and passes in the name field of the record as a parameter. So i am using a WHERE statement in my query so I only pull the extra fields for that record. I am getting the error:
System.Data.SqlClient.SqlException:Invalid column name '42'
Where 42 is the value from the name field from the database.
my query is
string selectStr = "SELECT name, castNotes, triviaNotes FROM tableName WHERE name =\"" + show + "\"";
I do not know if it is a problem with my query or something is wrong with the database, but here is the rest of my code for reference.
NOTE: this all works perfectly when I grab all of the records, but I only want to grab the record that I ask my webservice for.
public class ktvService : System.Web.Services.WebService {
[WebMethod]
public string moreInfo(string show) {
string connectionStr = "MyConnectionString";
string selectStr = "SELECT name, castNotes, triviaNotes FROM tableName WHERE name =\"" + show + "\"";
SqlConnection conn = new SqlConnection(connectionStr);
SqlDataAdapter da = new SqlDataAdapter(selectStr, conn);
DataSet ds = new DataSet();
da.Fill(ds, "tableName");
DataTable dt = ds.Tables["tableName"];
DataRow theShow = dt.Rows[0];
string response = "Name: " + theShow["name"].ToString() + "Cast: " + theShow["castNotes"].ToString() + " Trivia: " + theShow["triviaNotes"].ToString();
return response;
}
}
Quick solution:
I believe you need single quotes in your selectStr:
string selectStr =
"SELECT name, castNotes, triviaNotes FROM tableName WHERE name = '" + show + "'";
More information:
In .NET, you'll want to be sure you close out any connections explicitly when you no longer need them. The easiest way to do this is to wrap using statements around any types that implement IDisposable, such as SqlConnection in this case:
using(SqlConnection conn = new SqlConnection(connectionStr))
{
SqlDataAdapter da = new SqlDataAdapter(selectStr, conn);
DataSet ds = new DataSet();
da.Fill(ds, "tableName");
DataTable dt = ds.Tables["tableName"];
DataRow theShow = dt.Rows[0];
string response = "Name: " + theShow["name"].ToString() + "Cast: " + theShow["castNotes"].ToString() + " Trivia: " + theShow["triviaNotes"].ToString();
return response;
}
Additionally, it looks like your code could be easily subject to SQL injection. What if someone submits a form with the value: fake name' OR 1=1;DROP DATABASE someDbName;--?
You'll want to take advantage of SQL parameters, something like:
SqlCommand cmd = new SqlCommand(
"SELECT name, castNotes, triviaNotes FROM tableName WHERE name = #show", conn);
cmd.Parameters.AddWithValue("#show", show);
Shouldn't the WHERE clause be WHERE name = '" + show + "'"; Strings should be enclosed in single quotes and not double quotes for SQL statements.
Also the System.Data.SqlClient namespace is for SQL Server and not MySQL. See MySQL official docs for connecting to MySQL via C#.