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How to return names of all columns?

Searching, I found the PRAGMA as a possible solution for my problem, but it only returns the index of each column. There's any other method to return all columns names?
I thought using a For to go through my column indexes returning their names would works fine, but I dont exactly know how the syntax of this would be, either the stop condition.
void FillColumnList()
{
try
{
string check = "SELECT * FROM PRAGMA table_info(Produtos)";
sqlCon.Open();
SQLiteCommand tst2 = new SQLiteCommand(check, sqlCon);
SQLiteDataReader rdr2 = tst2.ExecuteReader();
if (rdr2.HasRows)
{
while (rdr2.Read())
{
string columns = rdr2[0].ToString();
Columns.Add(columns);
}
sqlCon.Close();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message.ToString());
}
}
This code should return and fill the Global variable list Columns with the name of each column of "Produtos" table. Instead of it, my DataReader 'rdr2' return false in the HasRows, even when there's columns and Datas in my table "Produtos"

You can use the connection's GetSchema method to retrieve the column information. I'm using the following code to insert information my own class TableColumn not shown here:
string[] restrictions = new string[] { null, null, tableName };
using (DataTable columns = conn.GetSchema("Columns", restrictions)) {
int nameIndex = columns.Columns.IndexOf("COLUMN_NAME");
int ordinalPosIndex = columns.Columns.IndexOf("ORDINAL_POSITION");
int isNullableIndex = columns.Columns.IndexOf("IS_NULLABLE");
int maxLengthIndex = columns.Columns.IndexOf("CHARACTER_MAXIMUM_LENGTH");
int dataTypeIndex = columns.Columns.IndexOf("DATA_TYPE");
int isPrimaryKeyIndex = columns.Columns.IndexOf("PRIMARY_KEY");
int hasDefaultIndex = columns.Columns.IndexOf("COLUMN_HASDEFAULT");
int defaultValueIndex = columns.Columns.IndexOf("COLUMN_DEFAULT");
foreach (DataRow row in columns.Rows) {
var col = new TableColumn {
ColumnName = (string)row[nameIndex]
};
try {
col.ColumnNameForMapping = prepareColumnNameForMapping(col.ColumnName);
} catch (Exception ex) {
throw new UnimatrixExecutionException("Error in delegate 'prepareColumnNameForMapping'", ex);
}
col.ColumnOrdinalPosition = (int)row[ordinalPosIndex];
col.ColumnAllowsDBNull = (bool)row[isNullableIndex];
col.ColumnMaxLength = (int)row[maxLengthIndex];
string explicitDataType = ((string)row[dataTypeIndex]).ToLowerInvariant();
col.ColumnDbType = GetColumnDbType(explicitDataType);
col.ColumnIsPrimaryKey = (bool)row[isPrimaryKeyIndex];
col.ColumnIsIdentity = explicitDataType == "integer" && col.ColumnIsPrimaryKey;
col.ColumnIsReadOnly = col.ColumnIsIdentity;
if ((bool)row[hasDefaultIndex]) {
col.ColumnDefaultValue = GetDefaultValue(col.ColumnDbType, (string)row[defaultValueIndex]);
if (col.ColumnDefaultValue == null) { // Default value could not be determined. Probably expression.
col.AutoAction = ColumnAction.RetrieveAfterInsert;
}
}
tableSchema.ColumnSchema.Add(col);
}
}
You can simplify this code considerably if you only need the column names.

Linked Table Shows As read only

I am using C# to create a SQL Server view, then open an access database and link the table into access. The create view statement, open database statement and link statement work great BUT the catch here is it will always link the table as read-only. What piece o'code do I need to add or update current so that the view is not always linked as read-only?
string MasterDatabase = "R:\\Testing\\MasterDatabase.mdb";
DAO.Database dd;
DAO.DBEngine db = new DAO.DBEngine();
DAO.TableDef tdf9;
bool found = false;
DAO.TableDef tdf1;
string Table = "ServiceEntranceLog";
string TableAccess = "Service_Entrance_Log";
using (var connection = new SqlConnection(ConnectionStringHere))
using (var command = connection.CreateCommand())
{
using (var command4 = connection.CreateCommand())
{
command4.CommandText = "CREATE VIEW HelperView" AS SELECT * FROM monster.ServiceEntranceLog";
command4.ExecuteNonQuery();
}
}
if (_combobox1.SelectedItems.Contains("MasterDatabase"))
{
dd = db.OpenDatabase(CRDB);
try
{
string[] tableNames = new string[1] { TableAccess };
for (int q = tableNames.GetLowerBound(0); q <= tableNames.GetUpperBound(0); q++)
{
foreach (DAO.TableDef tabledef in dd.TableDefs)
{
string name = tableNames[q];
if (tabledef.Name == name) { found = true; }
try { if (found) { dd.TableDefs.Delete(name); } }
catch { }
}
}
}
catch { }
tdf1 = dd.CreateTableDef(TableAccess);
tdf1.Connect = connectionString;
tdf1.SourceTableName = Table;
dd.TableDefs.Append(tdf1);
}

Alritey, so it seems the issue is I needed to define a primary key when linking in the table into access so that the table would be updateable. Using this syntax does the trick
dd.Execute "CREATE UNIQUE INDEX SomeIndex ON SomeTable (PrimaryKeyColumn) WITH PRIMARY"

C# Create employee. Save to SQL Database using EF

I'm saving an employee to a SQL database. I'm saving Firstname, Lastname, Username and Password. How should I do this to prevent saving more than one identical username?
I've tried this:
private void CreateEmployee()
{
using (var db = new TidrapportDBEntities())
{
var user = (from p
in db.Login
where p.username != null
select p).ToList();
foreach (var vUser in user)
{
if (vUser.username == textBoxUsername.Text)
{
labelSuccessFail.Visible = true;
labelSuccessFail.Text = "Accountname already exist.";
break;
}
else
{
var userInfo = new Login();
var persInfo = new PersonalInformation();
persInfo.firstname = textBoxFirstname.Text;
persInfo.lastname = textBoxLastname.Text;
userInfo.username = textBoxUsername.Text;
userInfo.password = textBoxPassword.Text;
userInfo.employeeId = persInfo.employeeId;
db.Login.Add(userInfo);
db.PersonalInformation.Add(persInfo);
db.SaveChanges();
textBoxFirstname.Text = string.Empty;
textBoxLastname.Text = string.Empty;
textBoxUsername.Text = string.Empty;
textBoxPassword.Text = string.Empty;
labelSuccessFail.Visible = true;
labelSuccessFail.Text = "Successfully created account.";
}
}
}
}
Any tips what I can try?
Kind regards,
Kristian

You should have a unique constraint on the username field. Not sure if you're doing code first, model first or DB first in your EF, but you should be able to google how to get it set on your database using the right method. That will throw an exception if you try to save one, so that makes sure you can't have more than one.
You could also use LINQ statement to restrict the list of users to the user name you wish to create and then you're just down to checking a bool to see if a row is returned or not. That way you're not having to read the entire database table (which your "toList" is doing).
In your code example, you're getting all the users where they have a user name, you're then looping round them, but your conditional code only really works if the first one matches the user name you're trying to save, otherwise you are going to try and recreate a duplicate the second time around. So just to get your code working you could try:
private void CreateEmployee()
{
using (var db = new TidrapportDBEntities())
{
var user = (from p
in db.Login
where p.username != null
select p).ToList();
bool found = false;
foreach (var vUser in user)
{
if (vUser.username == textBoxUsername.Text)
{
found = true;
labelSuccessFail.Visible = true;
labelSuccessFail.Text = "Accountname already exist.";
break;
}
}
if(!found)
{
var userInfo = new Login();
var persInfo = new PersonalInformation();
persInfo.firstname = textBoxFirstname.Text;
persInfo.lastname = textBoxLastname.Text;
userInfo.username = textBoxUsername.Text;
userInfo.password = textBoxPassword.Text;
userInfo.employeeId = persInfo.employeeId;
db.Login.Add(userInfo);
db.PersonalInformation.Add(persInfo);
db.SaveChanges();

Insert data into database using LINQ

I wrote a very simple method. It saves data from class DayWeather to the database. Method checks if line with that day exist in table and update her or create a new line.
I am doing it by adding new class for LINQ and move table from Server Inspector to the constructor. It generate new class WeatherTBL.
Method itself looks like this:
public static void SaveDayWeather(DayWeather day)
{
using (DataClassesDataContext db = new DataClassesDataContext())
{
var existingDay =
(from d in db.WeatherTBL
where d.DateTime.ToString() == day.Date.ToString()
select d).SingleOrDefault<WeatherTBL>();
if (existingDay != null)
{
existingDay.Temp = day.Temp;
existingDay.WindSpeed = day.WindSpeed;
existingDay.Pressure = day.Pressure;
existingDay.Humidity = day.Humidity;
existingDay.Cloudiness = day.Cloudiness;
existingDay.TypeRecip = day.TypeRecip;
db.SubmitChanges();
}
else
{
WeatherTBL newDay = new WeatherTBL();
newDay.DateTime = day.Date;
newDay.Temp = day.Temp;
newDay.WindSpeed = day.WindSpeed;
newDay.Pressure = day.Pressure;
newDay.Humidity = day.Humidity;
newDay.Cloudiness = day.Cloudiness;
newDay.TypeRecip = day.TypeRecip;
db.WeatherTBL.InsertOnSubmit(newDay);
db.SubmitChanges();
}
}
}
When I tried to call him from UnitTest project:
[TestMethod]
public void TestDataAccess()
{
DayWeather day = new DayWeather(DateTime.Now);
DataAccessClass.SaveDayWeather(day);
}
It write, that test has passed successfully. But if look into table, it has`t chanched.
No error messages shows. Does anyone know whats the problem?
P.S. Sorry for my bad English.
UDP
Problem was in that:
"...db maybe copied to the debug or release folder at every build, overwriting your modified one". Thanks #Silvermind

I wrote simple method to save employee details into Database.
private void AddNewEmployee()
{
using (DataContext objDataContext = new DataContext())
{
Employee objEmp = new Employee();
// fields to be insert
objEmp.EmployeeName = "John";
objEmp.EmployeeAge = 21;
objEmp.EmployeeDesc = "Designer";
objEmp.EmployeeAddress = "Northampton";
objDataContext.Employees.InsertOnSubmit(objEmp);
// executes the commands to implement the changes to the database
objDataContext.SubmitChanges();
}
}

Please try with lambda expression. In your code, var existingDay is of type IQueryable
In order to insert or update, you need a variable var existingDay of WeatherTBL type.
Hence try using below..
var existingDay =
db.WeatherTBL.SingleOrDefault(d => d.DateTime.Equals(day.Date.ToString()));
if(existingDay != null)
{
//so on...
}
Hope it should work..

Linq to SQL
Detail tc = new Detail();
tc.Name = txtName.Text;
tc.Contact = "92"+txtMobile.Text;
tc.Segment = txtSegment.Text;
var datetime = DateTime.Now;
tc.Datetime = datetime;
tc.RaisedBy = Global.Username;
dc.Details.InsertOnSubmit(tc);
try
{
dc.SubmitChanges();
MessageBox.Show("Record inserted successfully!");
txtName.Text = "";
txtSegment.Text = "";
txtMobile.Text = "";
}
catch (Exception ex)
{
MessageBox.Show("Record inserted Failed!");
}

Data is not saving into database in a right manner

private void SaveButton_Click(object sender, EventArgs e)
{
try
{
if (CashPaymentGridView.Rows.Count > 1)
{
CashPaymentandReceivedE cashpament =new CashPaymentandReceivedE();
List<CashPaymentandReceivedE> cashpaymentList = new List<CashPaymentandReceivedE>();
foreach ( DataGridViewRow rows in CashPaymentGridView.Rows)
{
if (rows.IsNewRow )
{
break ;
}
cashpament.VR_NO= Convert.ToInt16(VoucherNoTextBox.Text);
cashpament.VR_DATE = VrDate.Value ;
cashpament.ETYPE = "CPV";
cashpament.USER_ID = "1";
cashpament.PARTY_ID= Convert.ToString (rows.Cells[2].Value) ;
cashpament.DESCRIPTION = Convert.ToString ( rows.Cells[3].Value);
cashpament.INVOICE = Convert.ToString(rows.Cells[4].Value);
cashpament.DEBIT = Convert.ToInt32(rows.Cells[5].Value);
cashpament.CREDIT = 0;
cashpaymentList.Add(cashpament);
cashpament = new CashPaymentandReceivedE();
cashpament.VR_NO =Convert.ToInt16(VoucherNoTextBox.Text);
cashpament.VR_DATE = VrDate.Value;
cashpament.ETYPE = "CPV";
cashpament.USER_ID = "1";
cashpament.PARTY_ID = NewAccountsDAL.Get_Id_Name ("CASH");
cashpament.DESCRIPTION = Convert.ToString(rows.Cells[3].Value);
cashpament.INVOICE = Convert.ToString(rows.Cells[4].Value);
cashpament.CREDIT = Convert.ToInt32(rows.Cells[5].Value);
cashpament.DEBIT = 0;
cashpaymentList.Add(cashpament);
}
if (CashPaymentandReceivedDAL.Save(cashpaymentList))
{
MessageBox.Show("SAVE SUCCESSFULLY...............");
ResetForm();
}
}
else
{
MessageBox.Show ("Please select atleast one record.....");
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message );
}
}
Stored Procedure for saving data is given as.
public static bool Save(List <CashPaymentandReceivedE> cashreceivedpayment)
{
bool blnResult = false;
SqlConnection objSqlConnection = new SqlConnection(ConnectionString.Connection);
//SqlTransaction objSqlTransaction = null;
try
{
objSqlConnection.Open();
//objSqlTransaction = objSqlConnection.BeginTransaction();
int R = 0;
while (R < cashreceivedpayment.Count )
{
SqlCommand objSqlCommand = new SqlCommand("CASHRECEIVED_Save", objSqlConnection);
objSqlCommand.CommandType = CommandType.StoredProcedure;
//SqlParameter objIdentityParameter = objSqlCommand.Parameters.Add("#PLED_ID", SqlDbType.BigInt);
//objIdentityParameter.Direction = ParameterDirection.Output;
//objSqlCommand.Parameters.AddWithValue("#PLED_ID", cashreceivedpayment[R].PLED_ID);
objSqlCommand.Parameters.AddWithValue("#COMPANY_ID", "1");
objSqlCommand.Parameters.AddWithValue("#PARTY_ID", cashreceivedpayment[R].PARTY_ID);
objSqlCommand.Parameters.AddWithValue("#VR_NO", cashreceivedpayment[R].VR_NO);
objSqlCommand.Parameters.AddWithValue("#ETYPE", cashreceivedpayment[R].ETYPE);
objSqlCommand.Parameters.AddWithValue("#VR_DATE", cashreceivedpayment[R].VR_DATE);
objSqlCommand.Parameters.AddWithValue("#DESCRIPTION", cashreceivedpayment[R].DESCRIPTION);
objSqlCommand.Parameters.AddWithValue("#DEBIT", cashreceivedpayment[R].DEBIT);
objSqlCommand.Parameters.AddWithValue("#CREDIT", cashreceivedpayment[R].CREDIT);
objSqlCommand.Parameters.AddWithValue("#USER_ID", cashreceivedpayment[R].USER_ID);
//objSqlCommand.Parameters.AddWithValue("#COMPNAY_ID", cashreceivedpayment[R].COMPANY_ID);
objSqlCommand.Parameters.AddWithValue("#DESCRIPTION2", "DESCRIPTION2");
objSqlCommand.Parameters.AddWithValue("#INVOICE", cashreceivedpayment[R].INVOICE);
objSqlCommand.ExecuteNonQuery();
R++;
blnResult = true;
}
}
catch (Exception ex)
{
//objSqlTransaction.Rollback();
MessageBox.Show(ex.Message);
}
finally
{
//objSqlTransaction.Commit();
objSqlConnection.Close();
}
return blnResult;
}
When i save the record, one record should be of Party_id and one should be of cash.
but when i select more than one record just one entry saving to cash. when when i load the record jst one record is loaded.plz help if u understand.....

You're creating one CashPaymentandReceivedE object, and adding the reference to it on each iteration of the list. You're then also changing all the data within that single object on each iteration. Just move this line:
CashPaymentandReceivedE cashpament =new CashPaymentandReceivedE();
... inside your foreach statement and the problem should be resolved.
Before you do so though, make sure you understand why your code is behaving like this. It's really important to understand that the list doesn't contain objects - it contains references to objects. In your case, it would contain several references to a single object, until you fix it.
I'd also strongly suggest using a foreach in your Save method - or if you really need the index for some reason, use a for loop instead of a while.