public static SqlConnection OpenConnection2DB()
{
string s = #"Data Source=********;Initial Catalog=Parking;User ID=sa;Password=*******";
SqlConnection KetNoi = new SqlConnection(s);
KetNoi.Open();
return KetNoi;
}
public static void DongKetNoi(SqlConnection KetNoi)
{
KetNoi.Close();
}
public static DataTable TruyVanLayDuLieu(string sTruyVan, SqlConnection KetNoi)
{
SqlDataAdapter da = new SqlDataAdapter(sTruyVan, KetNoi);
DataTable dt = new DataTable();
da.Fill(dt);
return dt;
}
public static DataTable GetDataForm2DB()
{
string sTruyVan;
sTruyVan = "SELECT * FROM[parking].[dbo].[TicketMonth] AS A INNER JOIN[fishcm - cardlog].[dbo].[Cardlog] as B ON A.ID = B.ID and A.Stt = B.Stt";
con = OpenConnection2DB();
DataTable dt = TruyVanLayDuLieu(sTruyVan, con);
if (dt.Rows.Count == 0)
{
return null;
}
return dt;
}
The query is right, I checked it with SMSS and it works. My problem is how to open connection for 2 databases on the same server, parking and fishcm - cardlog.
I was looking for around, and see more people advised open 2 connection strings. But it is good in this case, both of databases cannot collate data with each other?
Related
I would really appreciate a help in this code. I have a DataSet with two tables; I need to create a relation based on two columns as primary key:
public DataSet GetAll()
{
string sql = $#"SELECT * FROM Journal ORDER BY JvNO, cYear;
SELECT * FROM JournalDetail ORDER BY JvNO, cYear";
using (SqlConnection connection = new SqlConnection(GlobalConfig.ConnString()))
{
connection.Open();
SqlCommand cmd = new SqlCommand(sql, connection);
SqlDataAdapter da = new SqlDataAdapter(sql, connection);
DataSet ds = new DataSet();
da.Fill(ds);
ds.Relations.Add("Journal_Batch", new DataColumn[] { ds.Tables[0].Columns["JvNO"], ds.Tables[0].Columns["cYear"] },
new DataColumn[] { ds.Tables[1].Columns["JvNO"], ds.Tables[1].Columns["cYear"] });
return ds;
}
}
Currently, I'm doing it like this and it's working but I need it with DataSet relation:
public DataSet GetJournalByID(int JVNO, int cYear)
{
string sql = $#"SELECT * FROM Journal WHERE JvNO = { JVNO } and cYear = { cYear };
SELECT * FROM JournalDetail WHERE JvNO = { JVNO } and cYear = { cYear };";
using (SqlConnection connection = new SqlConnection(GlobalConfig.ConnString()))
{
connection.Open();
SqlCommand cmd = new SqlCommand(sql, connection);
SqlDataAdapter da = new SqlDataAdapter(sql, connection);
DataSet ds = new DataSet();
da.Fill(ds);
return ds;
}
}
I don't know what's wrong with first code, as it returns all matching JvNO or Year.
i want to use the first one to fill two grids as follow:
private void GetData()
{
DataSet currentDs = new DataSet();
grdJournalDetails.DataSource = null;
grdJournal.DataSource = null;
JournalConnector journalConnection = new JournalConnector();
currentDs = journalConnection.GetAll();
grdJournal.DataSource = currentDs.Tables[0];
grdJournalDetails.DataSource = currentDs.Tables[1];
}
then with each row selected from grdJournal to display grdJournalDetails with related data without calling each time the second snippet of code.
i used Dapper and i'm familiar with it, but with devexpress grid, it have to be a datatable to use the event gvJournal_FocusedRowChanged, otherwise datarow returns always null;
Thanks for any suggestion.
Here is my code:
private List<string> readFromDatabase()
{
SQLiteConnection m_dbConnection = new SQLiteConnection("Data Source=" + fileName + ".sqlite;Version=3;");
string sql = "SELECT * FROM formsData";
m_dbConnection.Open();
SQLiteDataReader dr = DatabaseHandler.ExecuteCommandReader(sql, m_dbConnection);
List<string> tempList = new List<string>();
if(dr.HasRows)
{
while (dr.Read())
{
tempList.Add(Convert.ToString(dr["fieldName"]));
tempList.Add(Convert.ToString(dr["dataType"]));
tempList.Add(Convert.ToString(dr["numberOfCharacters"]));
}
}
return tempList;
}
I am trying to make it add each value from the database into the list, however it is only adding the last value found, from the final column. Does anyone know how to solve this? Thank you...
you can use a DataTable instead of DataReader (even though its possible to achieve the same result with DataReader).
please check that discussion: Why is DataTable faster than DataReader.
also its a better practice to use Try-Catchsteatments when connecting to databases.
here is an example (based on your code) how to achieve that task usingDataTable:
private List<string> readFromDatabase()
{
DataTable dt = PullData();
List<string> tempList = new List<string>();
if (dt != null & dt.Rows.Count >0)
{
for (int i = 0; i < dt.Rows.Count; i++)
{
tempList.Add(Convert.ToString(dt.Rows[i]["fieldName"]));
tempList.Add(Convert.ToString(dt.Rows[i]["dataType"]));
tempList.Add(Convert.ToString(dt.Rows[i]["numberOfCharacters"]));
}
}
return tempList;
}
public DataTable PullData()
{
try
{
string connString = #"your connection string here";
string query = "select * from table";
DataTable dataTable = new DataTable();
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(query, conn);
conn.Open();
// create data adapter
SqlDataAdapter da = new SqlDataAdapter(cmd);
// this will query your database and return the result to your datatable
da.Fill(dataTable);
conn.Close();
da.Dispose();
return dataTable;
}
catch (Exception ex)
{
return null;
}
}
Make sure your record set is positioned at the first row before you start iterating through it.
Also, do you really want to take all the rows of the table and have them as sequential values in a list? Perhaps adding them to class might make more sense.
public class Record{
public string Name { get; set; }
public string Type { get; set; }
public int Size { get; set; }
}
The first 2 are function in a class and second is a code.Here i have one text box i.e txtlicense and combobox cboaccident type and combobox consists 2 selecting item i.e Death and Major.Now if i input licensenumber in txtlicense and select Death option from combobox which are present in data base it shows the ouput as per required , but problem is that if i input the licensenumber in textbox and select major option from combobox which are already present in database and press the button it didn't show any ouptput for major option.
public DataTable Checkdeathaccident(string LicenseNumber, string PhysicalStatus)
{
SqlConnection con = new SqlConnection("Data Source=(LocalDB)\\MSSQLLocalDB; Integrated Security=True; Initial Catalog=tprojectDB;");
string sql = "select DeathNumber,ReportNumber,Date from tblAccident where LicenseNumber=#LicenseNumber and PhysicalStatus=#PhysicalStatus";
SqlCommand cmd = new SqlCommand(sql, con);
cmd.Parameters.AddWithValue("#LicenseNumber", LicenseNumber);
cmd.Parameters.AddWithValue("#PhysicalStatus", PhysicalStatus);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dan = new DataTable();
da.Fill(dan);
return dan;
}
public DataTable Checkmajoraccident(string LicenseNumber, string PhysicalStatus)
{
SqlConnection con = new SqlConnection("Data Source=(LocalDB)\\MSSQLLocalDB; Integrated Security=True; Initial Catalog=tprojectDB;");
string sql = "select DeathNumber,ReportNumber,Date from tblAccident where LicenseNumber=#LicenseNumber and PhysicalStatus=#PhysicalStatus";
SqlCommand cmd = new SqlCommand(sql, con);
cmd.Parameters.AddWithValue("#LicenseNumber", LicenseNumber);
cmd.Parameters.AddWithValue("#PhysicalStatus", PhysicalStatus);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dl = new DataTable();
da.Fill(dl);
return dl;
}
private void button10_Click_1(object sender, EventArgs e)
{
DataTable dan = pac.Checkdeathaccident(txtlicense.Text, cboaccidentype.Text);
if (dan.Rows.Count > 0)
{
if (cboaccidentype.Text == "Death")
{
dataGridView2.DataSource = dan;
}
else
{
DataTable dl = pac.Checkmajoraccident(txtlicense.Text, cboaccidentype.Text);
if (dl.Rows.Count > 0)
{
if (cboaccidentype.Text == "Major")
{
dataGridView2.DataSource = dl;
}
}
}
}
else
{
MessageBox.Show("No Record Found");
}
}
As Paul mentioned you have the same functions running to fill the same gridview with the same select query, you could refactor to this and it should work, I didn't test this just an idea.
public DataTable checkAccident(string LicenseNumber, string PhysicalStatus)
{
SqlConnection con = new SqlConnection("Data Source=(LocalDB)\\MSSQLLocalDB; Integrated Security=True; Initial Catalog=tprojectDB;");
string sql = "select DeathNumber,ReportNumber,Date from tblAccident where LicenseNumber=#LicenseNumber and PhysicalStatus=#PhysicalStatus";
SqlCommand cmd = new SqlCommand(sql, con);
cmd.Parameters.AddWithValue("#LicenseNumber", LicenseNumber);
cmd.Parameters.AddWithValue("#PhysicalStatus", PhysicalStatus);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dl = new DataTable();
da.Fill(dl);
return dl;
}
private void button10_Click_1(object sender, EventArgs e)
{
DataTable dan = pac.checkAccident(txtlicense.Text, cboaccidentype.Text);
if (dan.Rows.Count > 0)
{
dataGridView2.DataSource = dan;
}
else
{
MessageBox.Show("No Record Found");
}
}
I am trying to compare two databases from different dates. I want to load my 'Orders' table from the ending database into a DataTable, then convert that DataTable to a Dictionary<string,int> where string = OrderNumber and int = ClientNumber.
Once I have the Dictionary into memory, I will run my function that goes out to the beginning database and performs a atrOrdersEND.ContainsKey(ordernumber) check. If it is exists nothing will be done, if it does not exist, I want the information of the DataRow to be saved somewhere.
Is this the best way to go about this?
If not, how should I?
static public DataTable getDatabaseInfo(string DB)
{
DB = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + DB;
OleDbConnection conn = new OleDbConnection(DB);
string query = "SELECT * FROM ORDERS;";
OleDbCommand cmd = new OleDbCommand(query, conn);
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataTable dt = new DataTable();
conn.Open();
try
{
da.Fill(dt);
}
catch (OleDbException ex)
{
}
return dt;
}
static Dictionary<string,int> ToDictionary(DataTable DT)
{ //this doesn't work, I get the 'An item with the same key has already been added' error
var Dict = (from order in DT.AsEnumerable()
select new
{
OrderNumber = order.Field<string>("OrderNumber"),
ClientNumber = order.Field<int>("Client")
}).AsEnumerable()
.ToDictionary(k => k.OrderNumber, v => v.ClientNumber);
return Dict;
}
static public void CheckHistoryBEG(string DB)
{
DB = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + DB;
OleDbConnection conn = new OleDbConnection(DB);
string query = "SELECT * " +
"FROM Orders";
OleDbDataAdapter adapter = new OleDbDataAdapter(query, conn);
DataTable dt = new DataTable();
try
{
adapter.Fill(dt);
for (int i = 0; i <= dt.Rows.Count - 1; i++)
{
string ordernumber = dt.Rows[i]["OrderNumber"].ToString();
if (atrOrdersEND.ContainsKey(ordernumber))
{
atrOrdersEND[ordernumber] = atrOrdersEND[ordernumber] + 1;
}
else
{
atrOrdersEND.Add(ordernumber, 1);
}
}
}
catch (OleDbException ex)
{
}
}
public Main()
{
DataTable EndDB_Data = getDatabaseInfo(endDBLocation);
Dictionary<string, int> atrOrdersBEG = ToDictionary(EndDBData);
CheckHistoryBEG(beginningDBLocation);
}
You can avoid writing any C# code by using linked tables in your MS Access database. From one DB you can reference the table in the other database. Then you can do joins or existence queries between the two databases.
I have a homework about database connection via ms access.
I prepared my database and saved it as dbMert and put it to debug / bin
This is my CustomerDatabase class for connecting to database:
static class CustomerDatabase
{
static string connectionstring = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=dbMert.mdb";
static OleDbConnection connection = null;
static OleDbCommand command = null;
public static void ConnectToDatabase()
{
if (connection == null)
{
connection = new OleDbConnection(connectionstring);
command = new OleDbCommand();
command.Connection = connection;
command.CommandText = "select * from Customer";
}
}
public static DataTable executeSelect(string sql)
{
ConnectToDatabase();
DataTable dt = null;
dt = new DataTable();
command.CommandText = sql;
OpenConnection();
OleDbDataReader datareader = command.ExecuteReader();
dt.Load(datareader);
datareader.Close();
CloseConnection();
return dt;
}
public static void OpenConnection()
{
try
{
if (connection != null)
{
connection.Open();
}
}
catch (Exception ex)
{
}
}
public static void CloseConnection()
{
if (connection != null)
{
connection.Close();
}
}
}
}
Form: In constructor i try to connect to database
public Form1()
{
InitializeComponent();
CustomerDatabase.ConnectToDatabase();
}
and in form's load i try to take tuples to datagridview but nothing happens :S
private void Form1_Load(object sender, EventArgs e)
{
string sql1 = "select * from Customer";
DataTable dt = CustomerDatabase.executeSelect(sql1);
}
Regardless of other things (such as not keeping a single connection open, using using statements etc) you're not connecting your newly-loaded DataTable to your DataGridView at all. Your Form1_Load method just loads the data into a DataTable, then effectively throws it away.
I suspect you want something like:
dataGridView.DataSource = dt;
at the end of the method.
EDIT: Note that this is also a really bad idea in your OpenConnection code:
catch (Exception ex)
{
}
That basically says, "If something goes wrong, don't bother recording that fact or changing how the rest of the code works - just keep going as if nothing had happened."
Why are you catching the exception at all?
Try to write simple code. I suggest you to use OleDbDataAdaper, its Fill() method populate the DataTable easily.
You may use |DataDirectory| if you are using database (.mdb) located under Bin\Debug folder.
static string connectionstring = #"Provider=Microsoft.ACE.OLEDB.12.0;
Data Source=|DataDirectory|\dbMert.mdb";
Or
static string connectionstring = #"Provider=Microsoft.ACE.OLEDB.12.0;
Data Source=x:\full_path\dbMert.mdb";
Or
static string connectionstring = #"Provider=Microsoft.Jet.OLEDB.4.0;
Data Source=x:\full_path\dbMert.mdb";
static class Test
{
static string connectionstring = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=dbMert.mdb";
public static DataTable executeSelect(string sql)
{
DataTable dt = new DataTable();
OleDbDataAdapter adapter = new OleDbDataAdapter(sql,connectionString);
adapter.Fill(dt);
return dt;
}
}
Add following code in form_load handler,
string sql1 = "select * from Customer";
DataTable dt = Test.executeSelect(sql1);
DataGridView1.DataSource=dt;
When I move the DB-file to bin/debug, an error message states "4.0 is not installed".
However, when I move it to bin, the problem is solved.
My code:
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source= ..\\dbMert.mdb";
con.Open();
recordları
DataSet ds = new DataSet();
DataTable dt = new DataTable();
ds.Tables.Add(dt);
OleDbDataAdapter da = new OleDbDataAdapter();
da = new OleDbDataAdapter("Select * from Customer", con);
da.Fill(dt);
dataGridView1.DataSource = dt;
foreach (DataRow row in dt.Rows)
{
foreach (DataColumn col in dt.Columns)
if(col.ToString() == "emailAdress")
comboBox1.Items.Add(row[col]);
}
con.Close();