Problem to store a oracle sql result into a variable

Question

Hello everyone,
I'm working on a little project that use c#, Oracle ODT and asp.net, so here is the thing, I need to save the result of a sequence (SECNUM.NEXTVAL ) into a variable, then call that value from many inserts and querys and for last make the commit. My problem is that I don't know how to convert the string result to a number and the call it from the statements. Always brings two errors, one is invalid number because Im sending a string and the another is that if I comment the line cmd.ExecuteNonQuery(); the script runs but no commit happens.
This is my code, is attached to a button:
C# Syntax (Toggle Plain Text)
string oradb = "Data Source=BBDD;User Id=DEMO;Password=DEMO;";
string cmd1 = "SELECT SECNUM.NEXTVAL FROM DUAL";
OracleConnection conn = new OracleConnection(oradb);
conn.Open();
OracleParameter parm = new OracleParameter();
parm.OracleDbType = OracleDbType.Decimal;
OracleCommand cmd = new OracleCommand();
cmd.Connection = conn;
cmd.Parameters.Add(parm);
cmd.CommandText = "INSERT INTO DEMOINCI (CODINCI, CODCLI) VALUES (('" + cmd1 +"'), 'TEST')";
cmd.CommandText = "INSERT INTO DEMOINCILIN (CODINCI,CODLIN) VALUES (('" + cmd1 +"'),1)";
cmd.CommandType = CommandType.Text;
cmd.ExecuteNonQuery();
So my problem is that the column CODINCI is a column number of (9) and not a VARCHAR and can not be changed because is already have data, so when I use the code of the example, Oracle return an error saying Invalid number (of course).
With the help of a friend I tried to put with the cast like this cmd.CommandText = "INSERT INTO DEMOINCI (CODINCI, CODCLI) VALUES (" + "CAST(" + cmd1 + "AS NUMBER), 'TEST')"; and it works but only if I comment the line cmd.ExecuteNonQuery();, so the commit never happend and of course there is no insert in the database.
¿It is so difficult to store a result of an SQL into a variable and then call it back on a statement?, on Oracle Forms you create a cursor like cursor=CVAL SELECT SECNUM.NEXTVAL VAL FROM DUAL and that it you can then use the VAL result into all other queries of the same form an retrieving with the :VAL option.
Thanks for all the help.

Answer 1

I just had to do something similar for my C# class, using SQL Server. The primary key for a "Customers" table was an auto-incrementing integer. After inserting a new customer I had to retrieve and display the primary key:
string selectStatement = "SELECT IDENT_CURRENT('Customers') from Customers";
SqlCommand selectCommand = new SqlCommand(selectStatement, connection);
int customerID = Convert.ToInt32(selectCommand,ExecuteScalar());
The ExecuteScalar() method of selectCommand returned the first column of the first row of the dataset, which in this case was the key of the new Customers record, as an object. Convert.ToInt32() converted the key to an integer.
Once you store SECNUM.NEXTVAL as an integer, you can use it to create a Parameter for the Command object.
HTH.