I'm trying to return the InvoiceID from the database but it keeps returning -1.
I'm trying to select the invoice ID From tblInvoice to display it on a form and also use it to insert it into a second table that has a one to many relationship with tblInvoice.
try
{
conn = new SqlConnection(conString);
conn.Open();
string select = "SELECT TOP 1 FId FROM tblFaktuur ORDER BY FId DESC";
SqlCommand cmd1 = new SqlCommand(select, conn);
i = (int)cmd1.ExecuteNonQuery();
}
catch (Exception e)
{
System.Windows.Forms.MessageBox.Show("ReadInvoiceNumber()" + e.Message);
}
return i;
When Running the query SELECT TOP 1 FId FROM tblFaktuur ORDER BY FId DESC in SQL Server it returns the value of 6 which is the last Invoice ID.
Think about that code. How do you expect a method called ExecuteNonQuery to handle a Query? Change that to ExecuteScalar. This work Perfectly Thanks to #Camilo Terevinto, i will be doing research to improve my skills atleast i know what is wrong.
I'm trying to get the last row of a table using C# but it doesn't seem to be working, this is my code:
MySqlConnection cnnGetID = new MySqlConnection(Global.connectionString);
cmd = "SELECT ContactID FROM Contacten ORDER BY ContactID DESC LIMIT 1";
MySqlCommand cmdGetID = new MySqlCommand(cmd, cnnGetID);
cnnGetID.Open();
string contactID = cmdGetID.ExecuteNonQuery().ToString();
MessageBox.Show(contactID);
cnnGetID.Close();
The value this returns is -1 while it should be returning 59.
The strange thing is is that when I run this command in phpmyadmin I DO get 59.
Any ideas on why C# is not returning the correct value but phpmyadmin is?
EDIT: problem solved, should've uses ExecuteScalar(). Looks like I've been staring at my monitor for a bit too long...
You need to use ExecuteScalar instead of ExecuteNonQuery.
MySqlConnection cnnGetID = new MySqlConnection(Global.connectionString);
cmd = "SELECT ContactID FROM Contacten ORDER BY ContactID DESC LIMIT 1";
MySqlCommand cmdGetID = new MySqlCommand(cmd, cnnGetID);
cnnGetID.Open();
string contactID = cmdGetID.ExecuteScalar().ToString();
MessageBox.Show(contactID);
cnnGetID.Close();
This should resolve your issue.
The value this returns is -1 while it should be returning 59.
No, it's behaving exactly as documented by IDbCommand.ExecuteNonQuery:
For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command. For all other types of statements, the return value is -1.
You're using a SELECT statement - a query. So instead of executing ExecuteNonQuery, you should be using ExecuteQuery and iterating over the results, or ExecuteScalar, given that you know you'll have a single result:
string contactID = cmdGetID.ExecuteScalar().ToString();
you should use ExecuteScalar because you are returning value ExecuteNonQuery returns the number of rows affected by update delete or insert opeation
you can check this for more info
ExecuteNonQuery
Returns the number of rows affected.
ExecuteScalar
Executes the query, and returns the first column of the first row in
the result set returned by the query. Additional columns or rows are
ignored.
for more information you can check this The MySqlCommand Object
you can use query like this
MySqlConnection cnnGetID = new MySqlConnection(Global.connectionString);
cmd = "SELECT TOP 1 ContactID FROM Contacten ORDER BY ContactID";
MySqlCommand cmdGetID = new MySqlCommand(cmd, cnnGetID);
cnnGetID.Open();
string contactID = cmdGetID.ExecuteNonQuery().ToString();
MessageBox.Show(contactID);
cnnGetID.Close();
queryShelf = "SELECT * FROM shelftable WHERE ShelfId= #ShelfId";
//Create Mysql Command
MySqlCommand cmd = new MySqlCommand(queryShelf, connection);
cmd.Parameters.Add(new MySqlParameter("#ShelfId", MySqlDbType.VarChar)).Value = MainWindow.shelfIds[i];
//ExecuteScalar will return one value
int Count = int.Parse(cmd.ExecuteScalar() + "");
ExecuteScalar is used to return a single value, you are selecting complete records. So normally you use ExecuteReader and use Read to get all records.
But actually you can use ExecuteScalar with SELECT *. What happens is that the first column of the first row in the result set is returned, or a null reference if the result set is empty.
Since you get NULL it seems that the filter doesn't return a record.
Since you want a count you could change your query to:
queryShelf = "SELECT COUNT(*) FROM shelftable WHERE ShelfId= #ShelfId";
// ...
int Count = (int) cmd.ExecuteScalar();
Now you never get null but the count of records, 0 if no record exists with this ShelfId.
I'm trying to check if table exists, but not working correctly.
For some reason, count always returns -1. I already have a table in the database. It
should return 1?
SearchEntities db = new SearchEntities();
var qry3 = "";
var sql4 = "SELECT Count(*) FROM SearchDB.INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'portland'";
var count = db.Database.ExecuteSqlCommand(sql4);
ExecuteSqlCommand doesn't return data, it always returns an Int32, which is the number of rows processed by the SQL script when it's a DDL/DML command.
You want SqlQuery<TElement>(String, Object[]) instead.
var count = db.Database.SqlQuery<int>(sql4).Single();
ExecuteStoreQuery Directly Execute Commands Against the Data Source.
int result = entity.ExecuteStoreQuery<int>(#"
IF EXISTS (SELECT * FROM sys.tables WHERE name = 'TableName')
SELECT 1
ELSE
SELECT 0
").SingleOrDefault();
See answer here.
Here's my code
// SqlCommand query = new SqlCommand("INSERT INTO devis (idProposition, identreprise, tauxHoraire, fraisGenerauxMO, fraisGenerauxPiece, beneficeEtAleas, idStatut, prixUnitaireVenteMO ) VALUES(#idproposition, #identreprise, #tauxHoraire, #fraisGenerauxMO, #fraisGenerauxPiece, #beneficeEtAleas, 1, #prixUnitaireVenteMO) ", Tools.GetConnection());
SqlCommand query = new SqlCommand("INSERT INTO devis (idProposition, identreprise, tauxHoraire, fraisGenerauxMO, fraisGenerauxPiece, beneficeEtAleas, idStatut, prixUnitaireVenteMO, alerteEntrepriseEnvoyee,fraisDeplacement ) VALUES(1051, 85, 20, 2, 2, 2.2, 1, 88,0,-1) ", Tools.GetConnection());
//query.Parameters.AddWithValue("idproposition", this.ID);
//query.Parameters.AddWithValue("identreprise", competitor.ID);
//query.Parameters.AddWithValue("tauxHoraire", competitor.CoefTauxHoraire);
//query.Parameters.AddWithValue("fraisGenerauxMO", competitor.CoefFraisGenerauxMO);
//query.Parameters.AddWithValue("fraisGenerauxPiece", competitor.CoefFraisGenerauxPiece);
//query.Parameters.AddWithValue("beneficeEtAleas", competitor.CoefBeneficeEtAleas);
//query.Parameters.AddWithValue("prixUnitaireVenteMO", Math.Round(competitor.CoefTauxHoraire * competitor.CoefFraisGenerauxMO * competitor.CoefBeneficeEtAleas, 2));
bool insertOK = (query.ExecuteNonQuery() == 1);
if (insertOK)
{
// DO SOMETHING
}
insertOk is false but in the database the row is inserted with all the information that I specified
I rebuilt the query manually to see if the problem came from the query.Parameters, it inserts without error again into the database but insertOk is still false! I even added two other fields which aren't supposed to be null but the activity is the same in both cases
any ideas?
ExecuteNonQuery it claims to return The number of rows affected.. This is incorrect, as there is no way for the client to know the number of rows affected. The documentation incorrectly assumes that the engine will report the number of rows affected, but that is subject to the session SET NOCOUNT state. Do not write code that assumes the NOCOUNT is always on. If you need to know the number of rows affected use the OUTPUT clause. Relying on the ##ROWCOUNT or the SET NOCOUNT state is subject to many many corner cases where the value is incorrect from one point of view or another.
For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command.
When a trigger exists on a table being inserted or updated, the return value includes the number of rows affected by both the insert or update operation and the number of rows affected by the trigger or triggers. For all other types of statements, the return value is -1. If a rollback occurs, the return value is also -1.
ExecuteNonQuery method returns System.Int32
Executes a Transact-SQL statement against the connection and returns
the number of rows affected.
Return Value
Type: System.Int32
The number of rows affected.
Since your query.ExecuteNonQuery() returns 2, it is too obvious 2 == 1 returns false.
Your query will be;
bool insertOK = (2 == 1);
DEMO.
Try using SqlDataAdapter such that :
SqlDataAdapter Adabter = new SqlDataAdapter();
Adabter.InsertCommand = new SqlCommand("INSERT INTO devis values(#idProposition, #identreprise), Tools.GetConnection());
Adabter.InsertCommand.Parameters.Add("#idproposition",SqlDbType.Int).Value = yorID;
Adabter.InsertCommand.Parameters.Add("#identreprise", SqlDbType.Int).Value = yorID;
Tools.OpenConnection();
int result = Adabter.InsertCommand.ExecuteNonQuery();
Tools.CloseConnection();
if( result > 0 )
{
MessageBox.Show("Information Added");
}else
{
MessageBox.Show("Error");
}
Same issue here with an UPDATE query. In my case I had to add "set nocount off" to the SQL. Example code:
string sql =
$#"set nocount off;update PRODUCT_PLAN
set WORKING_STATUS = 'P',
user_id = #USER_ID
where workorder_base_id = #BASE_ID
";
SqlCommand cmd = new SqlCommand();
cmd.Connection = connection;
cmd.CommandType =CommandType.Text;
cmd.Parameters.AddWithValue("#USER_ID", opl.USER_ID);
cmd.Parameters.AddWithValue("#BASE_ID", opl.WORKORDER_BASE_ID);
cmd.CommandText = sql;
// Nr of rows updated in retval
int retval = cmd.ExecuteNonQuery();