I want to shift some variables by one. I searched for the command for it but I couldn't find. If anybody knows it please help me.
Here is the code:
private int shiftNumbers(int number)
{
int newNumber = 0;
string stm = "UPDATE devices SET number= #newNumber WHERE number>#number";
try
{
con.Open();
cmd = new MySqlCommand(stm, con);
cmd.Parameters.AddWithValue("#number", number);
}
catch (Exception e)
{
ErrorMessage = e.Message;
con.Close();
return null;
}
try
{
rdr = cmd.ExecuteReader();
while(rdr.Read()) {
newNumber = rdr.GetInt32(1);
cmd.Parameters.AddWithValue("#newNumber ", (newNumber-1));
}
}
catch (Exception e)
{
ErrorMessage = e.Message;
con.Close();
return null;
}
con.Close();
return 1;
}
I know this code useless but I show it for you to get the logic that I want to do.
I think your approach is wrong.
First, you read from the database, using a select statement;
Then you go over that result, your rdr.Read();
Then you create a new command, updating the original record;
Move forward in your reader (rdr) and repeat from 2 until you are done.
What you are doing now is impossible. You can't get a result set from an update, just a count affected.
Or, if you can, let your update statement do the calculation (it seems it is only subtracting one from the original number, so why not do that in SQL?):
string stm = "UPDATE devices SET number = number - 1 WHERE number>#number";
Yes, your code is really useless. In your update statement you are passing a parameter #newNumber bu not providing it. Closing the connection in catch block.
string stm = "UPDATE devices SET number= #newNumber WHERE number>#number";
First decide from where you are going to get the #newNumber value and then add that as parameter and use ExecuteNonQuery() method.
If you want pass the other parameter as well in your method and use it like
private int shiftNumbers(int number, int newNumber)
{
//int newNumber = 0;
string stm = "UPDATE devices SET number= #newNumber WHERE number>#number";
using(SqlConnection con = new SqlConnection(connectionString))
{
cmd = new MySqlCommand(stm, con);
SqlParameter paramNumber = new SqlParameter("#number", SqlDbType.Int);
paramNumber.Value = number;
SqlParameter paramNewNumber = new SqlParameter("#newNumber", SqlDbType.Int);
paramNewNumber.Value = newNumber;
cmd.Parameters.Add(paramNumber);
cmd.Parameters.Add(paramNewNumber);
con.Open();
cmd.ExecuteNonQuery();
}
//Rest of your code logic if any
}
Related
EDIT: I am not able to format my code below, if any one can fix it.
I am new to sql queries and still learning.
Table Name: CommissionSetupTable.
I want to display #Paisa if gross_amount is between the range of #FromRate and #ToRate
Below is my code:
string paisa;
private void load_commission_setup()
{
SqlCeConnection conn = null;
SqlCeCommand cmd = null;
SqlCeDataReader rdr = null;
try
{
conn =
new SqlCeConnection(
#"Data Source=|DataDirectory|\Database.sdf;Persist Security Info=False");
conn.Open();
int rowindex = purchaseBillTableDataGridView.Rows.Count - 1;
gross_amount = double.Parse(purchaseBillTableDataGridView[10, rowindex].Value.ToString());
// Gross Amount is between the ranges of FromRate and ToRate.
cmd = new SqlCeCommand("SELECT Paisa FROM CommissionSetupTable WHERE='" + gross_amount.ToString() + "' BETWEEN #FromRate AND #ToRate;", conn);
rdr = cmd.ExecuteReader();
if (rdr == null)
{
}
else
{
while (rdr.Read())
{
paisa = rdr["Paisa"].ToString();
}
rdr.Close();
cmd.Dispose();
}
}
finally
{
conn.Close();
int rowindex = purchaseBillTableDataGridView.Rows.Count - 1;
purchaseBillTableDataGridView[11, rowindex].Value = paisa;
}
}
The correct syntax to use here is the following
cmd = new SqlCeCommand(#"SELECT Paisa FROM CommissionSetupTable
WHERE #gross BETWEEN FromRate AND ToRate;", conn);
Notice that the two field names should not be prefixed with #, otherwise they will be considered parameters placeholders.
And now, before executing the command, add the parameter for the #gross placeholder
cmd.Parameters.Add("#gross", SqlDbType.Decimal).Value = gross_amount;
I don't know what is the exact datatype of the columns FromRate and EndRate, but
note that you should use the correct datatype for your parameter. Do not pass a string and expect the database engine do the conversion for you. (or worse concatenate your value to the rest of the sql using ToString()). This is always wrong also if sometime the database engine could understand your values.
EDIT
Also, following your comments below, it appears that this line is wrong
int rowindex = purchaseBillTableDataGridView.Rows.Count - 1;
If your DataGridView has the property AllowUserToAddRow set to True then you want to use
int rowindex = purchaseBillTableDataGridView.Rows.Count - 2;
because the first line points to the empty row added to the DataGridView for inserting a new record.
When calling the same query method twice in a session of the app, I get "DBCommandExcept"
As an experiment, I decided to dispose of the connection object at the end of the method, to see if that was the problem.
I no longer get the DBCommandExcept err msg, but instead get, "the connectionstring property has not been initialized."
IOW, it's sort of a Catch-22 situation at the moment. The pertinent code is:
string query = "SELECT Bla FROM Blah";
SqlCeCommand cmd = new SqlCeCommand(query);
cmd.CommandType = CommandType.Text;
SqlCeConnection conn = dbconn.GetConnection();
cmd.CommandType = CommandType.Text;//probably unnecessary
cmd.Connection = conn;
SqlCeDataReader myReader = cmd.ExecuteReader(CommandBehavior.SingleRow);
try
{
if (myReader.Read())
{
itemID = myReader.GetString(ITEMID_INDEX);
packSize = myReader.GetString(PACKSIZE_INDEX);
recordFound = true;
}
}
catch (Exception ex)
{
RRDR.LogMsgs.Append(string.Format("Exception in PopulateControlsIfVendorItemsFound(): {0}", ex.Message));
}
finally
{
myReader.Close();
//if (null != conn)
//{
// conn.Dispose();
//}
}
// Re: the commented-out block above: When it is active, the DBCommandExcept problem is not seen; however, I then get, "the connectionstring property has not been initialized"
I think the only non-SQL-CE-standard bit above is the dbConn.GetConnection(). Here's some of that code:
SqlCeConnection objCon = null;
. . .
public SqlCeConnection GetConnection()
{
return objCon;
}
private DBConnection() // class constructor
{
try
{
. . .
objCon = new SqlCeConnection(conStr);
objCon.Open();
. . .
Again, the error (either one, whichever one I "choose" to have) is seen only the second time through this method during one run of the app. The first time works fine.
UPDATE
I added the code below, and the comments tell the tale of woe:
// With conn check only, still get two consecutive DBCommandExcepts
// With cmd check only, still get two consecutive DBCommandExcepts
// With both, still get two consecutive DBCommandExcepts; IOW, all have the same effect
if (null != conn)
{
conn.Close();
}
if (null != cmd)
{
cmd.Dispose();
}
UPDATE 2
Based on unicron's suggestion, I tried using "using."
In two of the three cases (SqlCeCommand and SqlCeDataReader), converting to "using" made no diff; in the other one (SqlCeConnection), it raised the err msgs, "The ConnectionString property has not been initialized."
Still, though, the code is cleaner with the two usings, so thanks for that nudge in the best practices direction.
Here's what it looks like now:
private bool PopulateControlsIfPlatypusItemsFound()
{
const int ITEMID_INDEX = 0;
const int PACKSIZE_INDEX = 1;
bool recordFound = false;
try
{
string PlatypusId = txtPlatypus.Text.ToString().Trim();
string PlatypusItemId = txtUPC.Text.ToString().Trim();
string itemID = string.Empty;
string packSize = string.Empty;
string query = string.Format("SELECT ItemID, PackSize FROM PlatypusItems WHERE PlatypusID = {0} AND PlatypusItemID = {1}", PlatypusId, PlatypusItemId);
using (SqlCeCommand cmd = new SqlCeCommand(query))
{
cmd.CommandType = CommandType.Text;
SqlCeConnection conn = dbconn.GetConnection();
if ((null != conn) && (!conn.State.Equals(ConnectionState.Open)))
{
conn.Open();
TTBT.LogMsgs.Append("Connection opened");
}
cmd.CommandType = CommandType.Text;//probably unnecessary
cmd.Connection = conn;
using (SqlCeDataReader myReader = cmd.ExecuteReader(CommandBehavior.SingleRow))
{
if (myReader.Read())
{
itemID = myReader.GetString(ITEMID_INDEX);
packSize = myReader.GetString(PACKSIZE_INDEX);
recordFound = true;
}
}
txtID.Text = itemID;
txtSize.Text = packSize;
return recordFound;
}
}
catch (Exception ex)
{
TTBT.LogMsgs.Append(string.Format("Exception in PopulateControlsIfPlatypusItemsFound: {0} - {1}\r\n", ex.Message, ex.InnerException));
return recordFound;
}
}
UPDATE 3
I've come even closer to normalcy by replacing the custom connection code with the generic sort, adding another "using" to the mix:
private bool PopulateControlsIfVendorItemsFound()
{
const int ITEMID_INDEX = 0;
const int PACKSIZE_INDEX = 1;
bool recordFound = false;
DUCKBILL.LogMsgs.Append("Made it into frmEntry.PopulateControlsIfVendorItemsFound()\r\n");
try
{
string vendorId = txtVendor.Text.ToString().Trim();
string vendorItemId = txtUPC.Text.ToString().Trim();
string itemID = string.Empty;
string packSize = string.Empty;
if ( dbconn.isValidTable( "VendorItems" ) == -1 )
{
DUCKBILL.LogMsgs.Append("VendorItems not a valid table");//do not see this msg; good! VendorItems is seen as valid...
return false;
}
string query = string.Format("SELECT ItemID, PackSize FROM VendorItems WHERE VendorID = {0} AND VendorItemID = {1}", vendorId, vendorItemId);
using (SqlCeCommand cmd = new SqlCeCommand(query))
{
cmd.CommandType = CommandType.Text;
using (SqlCeConnection conn = new SqlCeConnection())
{
string filename = "\\badPlace2B\\CCRDB.SDF";
conn.ConnectionString = string.Format("Data Source = {0}", filename);
cmd.CommandType = CommandType.Text;//probably unnecessary/moot
cmd.Connection = conn;
conn.Open();
using (SqlCeDataReader myReader = cmd.ExecuteReader(CommandBehavior.SingleRow))
{
if (myReader.Read())
{
itemID = myReader.GetString(ITEMID_INDEX);
packSize = myReader.GetString(PACKSIZE_INDEX);
recordFound = true;
}
}
}
txtID.Text = itemID;
txtSize.Text = packSize;
return recordFound;
}
}
catch (Exception ex)
{
DUCKBILL.LogMsgs.Append(string.Format("Exception in PopulateControlsIfVendorItemsFound: {0} - {1}\r\n", ex.Message, ex.InnerException));
return recordFound;
}
}
...yet I still get "DBCommandExcept"...
As to "stop futzing around with opening the connection," isn't it necessary to do so? How could/should the code above be different?
UPDATE 4
What is even more bizarre is that now my debug log file has stopped being written. I have been writing it out both in the global exception handler AND in the main form's Closed event(), and it always has (until now) at least a few entries, but within the last couple of updates to the code, it is no longer being written...????
Both places global exception handler and main form's Closed event(), the code is like so:
public static bool inDebugMode = true;
. . .
if (CCR.inDebugMode)
{
DateTime dt = DateTime.Now;
string timeAsStr = string.Format("{0}_{1}_{2}_{3}.txt", dt.Hour, dt.Minute, dt.Second, dt.Millisecond);
using (StreamWriter file = new StreamWriter(timeAsStr))
{
// If the app closes normally, this is how the file is written; if it doesn't,
// (it crashed) it's written in PDAClient.ExceptionHandler()
file.WriteLine(SSCS.LogMsgs.ToString());
}
}
Since you are making several calls to a database file (that isn't going to change), I'd start out by defining your connection string and your SQL statements at the top of your class as global values:
private const int ITEMID_INDEX = 0;
private const int PACKSIZE_INDEX = 1;
private const string SQL_CONN_STR = "Data Source=\\badPlace2B\\CCRDB.SDF";
private const string SQL_GET_VENDOR_ITEMS = "SELECT ItemID, PackSize " +
"FROM VendorItems " +
"WHERE VendorID=#VendorID AND VendorItemID=#VendorItemID";
These never change, so there is no reason to define them again each time you call your routine.
Personally, I do not like inserting values into SQL statements, like you have shown. Rather, try to use Parameters.
To use Parameters, you'll need to look into your database to see what type of columns VendorID and VendorItemID are. My guess is that they are both int values, but these could be GUID like values, requiring VarChar type strings. If these are strings, you should write down what sizes the columns are defined as.
For example: Below, my Serial_Number column is the SqlDbType.NVarChar and the size is 50. An SqlCeParameter for this column would be:
cmd.Parameters.Add("#Serial_Number", SqlDbType.NVarChar, 50).Value = txtSerial_Number.Text.Trim();
Since I did not know what type of data you use, I created an enumerated type to show how each method would be used. If you do not have access to the table's design, the last resort is "AddWithValue" (I personally hate that one, because it makes me look like I don't know what my database has inside).
enum ParamStyle { AddWithValue, AddIntegers, AddVarChar }
To use this enumerated type, I modified the signature of your method to pass in that value:
private bool PopulateControlsIfVendorItemsFound(ParamStyle style) {
Obviously, you will not need this, because you should know what technique you are going to be coding with.
I wasn't able to figure out what your dbconn object was. Initially, I thought this was your SqlCeConnection, but that does not have an isValidTable method, so I just commented it out:
//if (dbconn.isValidTable("VendorItems") == -1) {
// DUCKBILL.LogMsgs.Append("VendorItems not a valid table");//do not see this msg; good! VendorItems is seen as valid...
// return false;
//}
Speaking of SqlCeConnection...
I combined your SqlCeCommand instance with your SqlCeConnection instance. Less code typically means fewer errors:
using (var cmd = new SqlCeCommand(SQL_GET_VENDOR_ITEMS, new SqlCeConnection(SQL_CONN_STR))) {
The CommandType, by default, is CommandType.Text, so this line is unnecessary:
// cmd.CommandType = CommandType.Text; (this is the default)
I moved most of your variable reading outside of the try/catch routine, as none of that should ever cause an exception to be generated.
Also, I used the more targeted SqlCeException instead of the general Exception. The only thing that could fail in the block is something SqlCe related, and the SqlCeException will give you better/more specific error messages than the general Exception object will.
} catch (SqlCeException err) {
So, what does it look like all put together?
Code:
enum ParamStyle { AddWithValue, AddIntegers, AddVarChar }
private const int ITEMID_INDEX = 0;
private const int PACKSIZE_INDEX = 1;
private const string SQL_CONN_STR = "Data Source=\\badPlace2B\\CCRDB.SDF";
private const string SQL_GET_VENDOR_ITEMS = "SELECT ItemID, PackSize FROM VendorItems WHERE VendorID=#VendorID AND VendorItemID=#VendorItemID";
private bool PopulateControlsIfVendorItemsFound(ParamStyle style) {
bool recordFound = false;
//DUCKBILL.LogMsgs.Append("Made it into frmEntry.PopulateControlsIfVendorItemsFound()\r\n");
string itemID = null;
string packSize = null;
//string vendorId = txtVendor.Text.Trim();
//string vendorItemId = txtUPC.Text.Trim();
//string query = string.Format("SELECT ItemID, PackSize FROM VendorItems WHERE VendorID = {0} AND VendorItemID = {1}", vendorId, vendorItemId);
//if (dbconn.isValidTable("VendorItems") == -1) {
// DUCKBILL.LogMsgs.Append("VendorItems not a valid table");//do not see this msg; good! VendorItems is seen as valid...
// return false;
//}
using (var cmd = new SqlCeCommand(SQL_GET_VENDOR_ITEMS, new SqlCeConnection(SQL_CONN_STR))) {
// cmd.CommandType = CommandType.Text; (this is the default)
if (style == ParamStyle.AddIntegers) { // Adding Integers:
cmd.Parameters.Add("#VendorID", SqlDbType.Int).Value = Convert.ToInt32(txtVendor.Text.Trim());
cmd.Parameters.Add("#VendorItemID", SqlDbType.Int).Value = Convert.ToInt32(txtUPC.Text.Trim());
} else if (style == ParamStyle.AddVarChar) { // Adding String Values
// NOTE: Here, you should look in your database table and
// use the size you defined for your VendorID and VendorItemID columns.
cmd.Parameters.Add("#VendorID", SqlDbType.VarChar, 25).Value = txtVendor.Text.Trim();
cmd.Parameters.Add("#VendorItemID", SqlDbType.VarChar, 50).Value = txtUPC.Text.Trim();
} else if (style == ParamStyle.AddWithValue) { // Adding as Objects (only if you don't know what the data types are)
cmd.Parameters.AddWithValue("#VendorID", txtVendor.Text.Trim());
cmd.Parameters.AddWithValue("#VendorItemID", txtUPC.Text.Trim());
}
try {
cmd.Connection.Open();
using (var myReader = cmd.ExecuteReader(CommandBehavior.SingleRow)) {
if (myReader.Read()) {
itemID = myReader.GetString(ITEMID_INDEX);
packSize = myReader.GetString(PACKSIZE_INDEX);
recordFound = true;
}
}
} catch (SqlCeException err) {
//DUCKBILL.LogMsgs.Append(string.Format("Exception in PopulateControlsIfVendorItemsFound: {0}\r\n", err.Message));
// (I never return from a 'catch' statement) return recordFound;
} finally {
if (cmd.Connection.State == ConnectionState.Open) {
cmd.Connection.Close();
}
}
}
if (recordFound) { // set these last, and set them OUTSIDE of the try/catch block
txtID.Text = itemID;
txtSize.Text = packSize;
}
return recordFound;
}
Happy Coding!
From the "Things that go bump in the database engine" department:
This function returns what looks like a valid value, but the record is not posted (no err msg):
private String GetInterpreterTicketIDSequenceVal()
{
con = new OracleConnection(oradb);
con.Open();
String query = "SELECT TO_CHAR(SYSDATE,'YYYYMMDD-') || LTRIM(TO_CHAR(ABC.SOMETABLEID.NEXTVAL, '000000')) FROM DUAL";
cmd = new OracleCommand(query, con);
cmd.CommandType = CommandType.Text;
//MessageBox.Show(cmd.ExecuteScalar().ToString());
return cmd.ExecuteScalar().ToString();
}
...SEEMS to work (returns a value, and the insertion is (seemingly) made without squawking)... yet, no record is inserted into the database.
This kludgy (sp?) function, OTOH:
private String GetSomeTableIDSequenceVal_Fake()
{
int iYear = DateTime.Now.Year;
int iMonth = DateTime.Now.Month;
int iDay = DateTime.Now.Day;
int iHour = DateTime.Now.Hour;
int iSecond = DateTime.Now.Second;
String sYear = iYear.ToString();
String sMonth = iMonth.ToString();
String sDay = iDay.ToString();
String sHour = iHour.ToString();
String sSecond = iSecond.ToString();
if (iMonth < 10)
{
sMonth = String.Format("0{0}", sMonth);
}
if (iDay < 10)
{
sDay = String.Format("0{0}", sDay);
}
if (iHour < 10)
{
sHour = String.Format("0{0}", sHour);
}
if (iSecond < 10)
{
sSecond = String.Format("0{0}", sSecond);
}
return String.Format("{0}{1}{2}-{3}{4}", sYear, sMonth, sDay, sHour, sSecond);
}
...works fine - the record is inserted into the database (the code that calls these functions follows).
It seems odd that they both return a string, yet one works, and one doesn't... that column doesn't have a constraint on it that is rejecting the value from the former function, so…???
Anyway, here’s the code that calls either of those functions, in context:
try
{
con = new OracleConnection(oradb);
con.Open();
String query = "INSERT INTO ABC.SOMETABLE (TICKETID, TICKETSOURCE, ABOUTSOMEID, CATEGORYID, CONTACTEMAIL) VALUES (:p_TICKETID, :p_TICKETSOURCE, :p_ABOUTSOMEID, :p_CATEGORYID, :p_CONTACTEMAIL)";
cmd = new OracleCommand(query, con);
cmd.CommandType = CommandType.Text;
// Params = TICKETID, TICKETSOURCE, ABOUTSOMEID, CATEGORYID, CONTACTEMAIL
OracleParameter p_TICKETID = new OracleParameter();
p_TICKETID.Direction = ParameterDirection.Input;
p_TICKETID.OracleDbType = OracleDbType.NVarchar2;
p_TICKETID.Size = 20;
// This doesn't allow the record to be inserted...???
//p_TICKETID.Value = GetSomeTableIDSequenceVal();
// ...but when I "fake it" below, the record IS inserted
//p_TICKETID.Value = GetSomeTableIDSequenceVal_Fake(); cmd.Parameters.Add(p_TICKETID);
OracleParameter p_TICKETSOURCE = new OracleParameter();
p_TICKETSOURCE.Direction = ParameterDirection.Input;
p_TICKETSOURCE.OracleDbType = OracleDbType.NVarchar2;
p_TICKETSOURCE.Size = 20;
p_TICKETSOURCE.Value = textBoxTicketSource.Text;
cmd.Parameters.Add(p_TICKETSOURCE);
OracleParameter p_ABOUTSOMEID = new OracleParameter();
p_ABOUTSOMEID.Direction = ParameterDirection.Input;
p_ABOUTSOMEID.OracleDbType = OracleDbType.Int32;
p_ABOUTSOMEID.Value = textBoxAboutSOMEID.Text;
cmd.Parameters.Add(p_ABOUTSOMEID);
OracleParameter p_CATEGORYID = new OracleParameter();
p_CATEGORYID.Direction = ParameterDirection.Input;
p_CATEGORYID.OracleDbType = OracleDbType.Int32;
p_CATEGORYID.Value = textBoxCategoryID.Text;
cmd.Parameters.Add(p_CATEGORYID);
OracleParameter p_CONTACTEMAIL = new OracleParameter();
p_CONTACTEMAIL.Direction = ParameterDirection.Input;
p_CONTACTEMAIL.OracleDbType = OracleDbType.NVarchar2;
p_CONTACTEMAIL.Size = 100;
p_CONTACTEMAIL.Value = textBoxContactEmail.Text;
cmd.Parameters.Add(p_CONTACTEMAIL);
try
{
cmd.ExecuteNonQuery();
}
catch (OracleException ex)
{
MessageBox.Show(ex.Message);
}
MessageBox.Show("Apparent success");
}
finally
{
con.Close();
con.Dispose();
}
Update:
I added Xaction support, and it seems to make no difference whatsoever:
I encased it in a Transaction, and it makes no difference:
OracleTransaction ot;
. . .
try
{
ot = con.BeginTransaction();
cmd.Transaction = ot;
cmd.ExecuteNonQuery();
ot.Commit();
}
catch (Exception ex)
{
ot.Rollback();
}
Update redux:
Luke made a good point about using two simultaneous connections; so, I changed that code to this:
private String GetInterpreterTicketIDSequenceVal()
{
String query = "SELECT TO_CHAR(SYSDATE,'YYYYMMDD-') || LTRIM(TO_CHAR(ABC.SOMETABLEID.NEXTVAL, '000000')) FROM DUAL";
OracleCommand oc = new OracleCommand(query, con);
oc.CommandType = CommandType.Text;
String s = oc.ExecuteScalar().ToString();
try
{
return s;
}
catch (OracleException ex)
{
MessageBox.Show(ex.Message);
return string.Empty;
}
}
...but still no joy in Mudville.
Update redux revisited:
I got it working; thanks everybody for your help and insight.
Actually, it had been working for awhile – my stupid query in Toad was the problem – I forgot that I was adding a slightly different value in new records than what I was querying for … so it looked like the records weren’t being added, but they really were.
tgif!
I tried running your code above and I was only able to reproduce problems with it if the INTERPRETERTICKETID sequence had gone beyond 999999. If you are having problems then there must be something that you are not telling us. For example, how is your table INTERPRETERTICKET defined? What constraints are on it? How is the sequence defined? Are there any triggers on the table?
Is there any need for your GetInterpreterTicketIDSequenceVal() method to use its own connection to the database? Can it not just use the same connection that the rest of your code does?
If your sequence INTERPRETERTICKETID has gone beyond 999999 then the TO_CHAR call will return a string of hashes:
SQL> select ltrim(to_char(999999, '000000')) from dual;
LTRIM(T
-------
999999
SQL> select ltrim(to_char(1000000, '000000')) from dual;
LTRIM(T
-------
#######
I put a PK constraint on the TICKETID column and after running your code twice, I got a constraint violation error.
EDIT:
In response to your comment, it is possible to use a trigger to populate the TICKETID column. You mentioned that your database apparently contains one such trigger, but without seeing how the trigger is defined, it's difficult to know what the problem with it could be.
I added the following trigger, and modified the C# code so that it didn't attempt to insert a value for TICKETID. I ran the C# code a few times and it seemed to work.
CREATE OR REPLACE TRIGGER INTERPRETERTICKETS_BI
BEFORE INSERT ON INTERPRETERTICKETS
FOR EACH ROW
BEGIN
SELECT TO_CHAR(SYSDATE,'YYYYMMDD-') || LTRIM(TO_CHAR(INTERPRETERTICKETID.NEXTVAL, '000000'))
INTO :new.TICKETID
FROM DUAL;
END;
/
the way you setup the parameters seems very strange since your parameter object end up without a name - try changing your code similar to this:
OracleParameter p_TICKETID = new OracleParameter("p_TICKETID", OracleDbType.NVarchar2, ParameterDirection.Input);
p_TICKETID.Size = 20;
I'm using c# in a ASP.Net web application.I have the following query:
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["chestionar"].ConnectionString);
con.Open();
SqlCommand cmd = new SqlCommand("select * from personal,Intrebari where personal.cod_numeric_personal=#cnp AND Intrebari.id_intrebare=14 AND Intrebari.id_intrebare=15 ", con);
cmd.Parameters.AddWithValue("#cnp", Session["sesiune_cnp"]);
SqlDataReader rdr;
rdr = cmd.ExecuteReader();
while (rdr.Read())
{
lbl1.Text = rdr["Nume"].ToString();
intrebare6.Text = rdr["Intrebari"].ToString();
intrebare7.Text = rdr["Intrebari"].ToString();
}
I want those two values for id_intrebare=14 and 15 to assign it to those 2 labels.How can i refer to those?
In order to read stuff from the reader you need to include it in the select statement for you sql, it is better to select it explicitly rather than use select *.
but you are not currently going to get any results returned because id_intrebare cannot be both 14 and 15
you then need to read id_intreabare ratherr than Intreabari.
Try this, notice the try catch block, I also changed your SQL query.
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["chestionar"].ConnectionString);
string qry="select * from personal,Intrebari where personal.cod_numeric_personal=#cnp AND Intrebari.id_intrebare IN (14,15);
SqlCommand cmd = new SqlCommand(qry, con);
cmd.Parameters.AddWithValue("#cnp", Session["sesiune_cnp"]);
try
{
con.Open();
SqlDataReader rdr= cmd.ExecuteReader();
if(rdr.HasRows)
{
while (rdr.Read())
{
lbl1.Text = rdr["Nume"].ToString();
intrebare6.Text = rdr["Intrebari"].ToString();
intrebare7.Text = rdr["Intrebari"].ToString();
}
}
}
catch(SQLException ex)
{
lblStatus.Text="An error occured"+ex.Message;
throw ex;
}
finally
{
con.Close();
con.Dispose();
}
If you want to assign texts to different numbered lables in a loop, you can refer to the control id with FindControl of the current page
int numeOrdinal = reader.GetOrdinal("Nume");
int intrebariOrdinal = reader.GetOrdinal("Intrebari");
int i = 1;
while (rdr.Read()) {
// Nume (Romanian) = Name
page.FindControl("lbl" + i).Text = reader.IsDBNull(numeOrdinal)
? ""
: rdr.GetString(numeOrdinal);
// Intrebari (Romanian) = Question
page.FindControl("intrebari" + i + 5).Text = reader.IsDBNull(intrebariOrdinal)
? ""
: rdr.GetString(intrebariOrdinal);
i++;
}
Try using cmd.ExecuteScalar it will return the first reuslt it finds so you have to define your conditions well. Also it returns object type so you will have to cast the result
I get no exception errors with the below code which could mean there is no problem with my sql statement. However upon trying to verify if it returns any value, i pass the returned items to a string value and try to display it in a message box.
the problem am facing is the message box only displays the name of the column and not the data ive requested from the table.
what could possibly be the problem? and please advice if theres a better way to work around this...
public void DisplayPurchase(OleDbConnection mDB)
{
openDB();
string sqlQuery;
OleDbCommand cmd;
OleDbDataReader rdr;
sqlQuery = "SELECT CustomerTable.[Youth ID], CustomerTable.Firstname, " +
"CustomerTable.Lastname, Youth.Purchaseid, Youth.NumbersOfSport, " +
"Youth.Price, Youth.TotalCostOfTraining, Youth.PercentageDiscount, " +
"Youth.AmountDue, Youth.DatePurchased" +
" FROM CustomerTable, Youth WHERE Youth.YouthID = CustomerTable.[Youth ID]" +
" AND CustomerTable.[Youth ID] = 7";
try
{
cmd = new OleDbCommand(sqlQuery, mDB);
rdr = cmd.ExecuteReader();
if (rdr.HasRows)
{
qtyInt1 = (int)rdr["Youth.NumbersOfSport"];
youthInt1 = (int)rdr["CustomerTable.[Youth ID]"];
firstStr1 = (string)rdr["CustomerTable.Firstname"];
purStr1 = (string)rdr["Youth.Purchaseid"];
lastStr1 = (string)rdr["CustomerTable.Lastname"];
priceStr1 = (string)rdr["Youth.Price"];
totalCstStr1 = (string)rdr["Youth.TotalCostOfTraining"];
discountStr1 = (string)rdr["Youth.PercentageDiscount"];
amtDueStr1 = (string)rdr["Youth.AmountDue"];
//purDate1 = (DateTime)rdr["Youth.DatePurchased"];
MessageBox.Show(firstStr1.ToString());
closeDB();
}
else
{
MessageBox.Show("Reader has no rows");
closeDB();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Thank you
I'm pretty sure that you have to call rdr.Read() before you can access any data from it. So, add that as the first line after if(rdr.HasRows())
You need to call Read() on the reader to read the first row.
if(rdr.HasRows) {
rdr.Read();
...
Best wishes,
Fabian
Have you tried:
firstStr1 = (string)rdr["Firstname"];
The fieldname in a datareader typically does not include the tablename prefix.
Remove the table names when you are retrieving the data:
qtyInt1 = (int)rdr["NumbersOfSport"];
youthInt1 = (int)rdr["Youth ID"]; // You may need to rename this one in the query
firstStr1 = (string)rdr["Firstname"];
purStr1 = (string)rdr["Purchaseid"];
lastStr1 = (string)rdr["Lastname"];
priceStr1 = (string)rdr["Price"];
totalCstStr1 = (string)rdr["TotalCostOfTraining"];
discountStr1 = (string)rdr["PercentageDiscount"];
amtDueStr1 = (string)rdr["AmountDue"];
Its amazing how this stuff works...
Id firstly like to thank everybody that contributed to solving this problem.Am really grateful for every alphabet posted.
sqlQuery = "SELECT Youth.YouthID, Firstname, Lastname, NumbersOfSport, Price, TotalCostOFTraining, PercentageDiscount, Purchaseid, AmountDue, DatePurchased FROM CustomerTable, Youth WHERE CustomerTable.YouthID = Youth.YouthID AND Youth.YouthID = "+ toSql(youthInt);
try
{
cmd = new OleDbCommand(sqlQuery, mDB);
rdr = cmd.ExecuteReader();
if (rdr.HasRows)
{
rdr.Read();
qtyInt1 = (int)rdr["NumbersOfSport"];
youthInt1 = (int)rdr["YouthID"];
firstStr1 = (string)rdr["Firstname"];
purInt1 = (int)rdr["Purchaseid"];
lastStr1 = (string)rdr["Lastname"];
priceStr1 = (string)rdr["Price"];
totalCstStr1 = (string)rdr["TotalCostOfTraining"];
discountStr1 = (string)rdr["PercentageDiscount"];
amtDueStr1 = (string)rdr["AmountDue"];
purDate1 = (DateTime)rdr["DatePurchased"];
closeDB();
}
else
{
MessageBox.Show("Reader has no rows");
closeDB();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
I had to call for the rdr.read(); functions as well as taking of the table referencing on the database columns and each help came from a different sources.....
thats awesome...
Thanks everybody...