Method to collect session variables

[coleresources]

I've been using a codepage that I redirect users to when they login in order to set session variables. I've been using the sql_lookup() function to set several variables which I've been told is not the best practice and slows down the login process due to the fact that the function is opening and closing the connection to the database each time I am doing the lookup. I am trying to change my methodology but I'm doing something wrong.

I'm using this script. I receive the error "function sequence error while getting result set data column 'FirstName'. Any help is appreciated.

dim conn as SQL::Connection
dim args as SQL::Arguments
dim sql as C
dim rs as SQL::ResultSet

args.set("userid",session.userid)
sql = "SELECT * FROM Users where users_id = :userid"


conn.Open("::name::MYDS")

conn.Execute(sql,args)
rs = conn.ResultSet

dim session.firstname as C=rs.data("FirstName")
dim session.lastname as C=rs.data("LastName")
dim session.id as N=rs.data("users_id")
dim session.bldrcode as C=rs.data("bldrcode")
dim session.fullname as C=alltrim(session.firstname) + " " + alltrim(session.lastname)

conn.FreeResult()

[pcaspa]

Re: Method to collect session variables

Hi,

Have you tried specifying the field you want rather than using "Select * ". (That's what I usually do)

(Good tip, I'm now going to replace SQL_Lookup in my login processing page)

Cheers

[Clipper87]

Re: Method to collect session variables

see this thread http://msgboard.alphasoftware.com/al...l=1#post661830

[Garry Flanigan]

Re: Method to collect session variables

Josh,
You have not closed the connection (not that this is your problem, as Frank has indicated):

conn.close()

conn.freeResult() does not close the connection.
Also, I do not think that every call of sql_lookup() opens and closes the connection!! I am interested to know where you got that info from.

[DaveF]

Re: Method to collect session variables

Hi Josh,

Like Peter mentioned, it is also more efficient to only specify the fields that you want. For example:

sql = "SELECT FirstName, LastName, users_id, bldrcode FROM Users where users_id = :userid"

You need to first position the result set to the first row before calling the "Data" method. You need to check the result of "NextRow" to make sure there is at least one row. "NextRow" will return .T. if you are positioned on a valid row and .F. if not. I have experienced interimittent problems using the debugger when there is only one row in the record set. It does not always return .T. when there is only one row. The example below is a way to counter this problem:

conn.Execute(sql,args)
rs = conn.ResultSet
rs.NextRow()

if .not. eval_valid("rs.data(1)")
' Show Error
exit function
end if

dim session.firstname as C=rs.data("FirstName")
dim session.lastname as C=rs.data("LastName")
dim session.id as N=rs.data("users_id")
dim session.bldrcode as C=rs.data("bldrcode")
dim session.fullname as C=alltrim(session.firstname) + " " + alltrim(session.lastname)

conn.Close()

[Peter.Greulich]

Re: Method to collect session variables

Also, I do not think that every call of sql_lookup() opens and closes the connection!!

Hhmm.. Why wouldn't it close the connection? If that is the only code in a script or function, do you believe that Alpha would just leave the connection open "forever"? That wouldn't make sense.

[Lenny Forziati]

Re: Method to collect session variables

sql_lookup() takes either a string containing a connection string or an open sql::connection as the first argument.

If you supply a connection string, sql_lookup() opens and the closes a connection.

If you supply an sql::connection, that connection is used directly and is neither opened nor closed by sql_lookup(). This allows you to open a connection externally and reuse it across sql_lookup() calls.

[DaveF]

Re: Method to collect session variables

I think I mentioned that sql_lookup opens and closes the connection because Josh was using a connection string and not an open connection object. He was also calling sql_lookup 10 or more times to get one field at a time so I recommended opening the connection and using SQL::Connection::Execute instead.

[coleresources]

Re: Method to collect session variables

Thank you all for your responses. Dave, can you tell me if this looks correct now? I am receiving the same error. It works in the interactive window when I hard set the session variable but I get a function sequence error when running it progromatically.

dim conn as SQL::Connection
dim rs as SQL::ResultSet
dim args as SQL::Arguments
dim sql as c

args.set("userid",session.userid)
sql = "SELECT FirstName, LastName, users_id, bldrcode FROM Users where users_id = :userid"
conn.Open("::name::MYDS")
conn.Execute(sql,args)
rs = conn.ResultSet
rs.NextRow()

if .not. eval_valid("rs.data(1)")
' Show Error
exit function
end if

dim session.firstname as C=rs.data("FirstName")
dim session.lastname as C=rs.data("LastName")
dim session.id as N=rs.data("users_id")
dim session.bldrcode as C=rs.data("bldrcode")
dim session.fullname as C=alltrim(session.firstname) + " " + alltrim(session.lastname)

[DaveF]

Re: Method to collect session variables

So in the debugger you can step through the code and it executes the rs.data("FirstName") correctly and sets session.firstname correctly to the value of the first name? How about if you remove the dim and just do the following?

session.firstname = rs.data("FirstName")

[pcaspa]

Re: Method to collect session variables

As a result of this thread I replaced about 20 SQL_Lookup()s in one of my login processing pages with code basically the same as yours. Except as DaveF suggested without the Dim. Login performance improved significantly (no surprise). I did get the same error as you when I had a syntax error in the SQL.

Maybe try and simplify and see if you can get only the FirstName field from the users table.

[Garry Flanigan]

Re: Method to collect session variables

Peter,

Hhmm.. Why wouldn't it close the connection? If that is the only code in a script or function, do you believe that Alpha would just leave the connection open "forever"? That wouldn't make sense.

If sql_lookup is using "c as a pointer to an open connection" (see http://wiki.alphasoftware.com/~alpha...ookup+Function) why would it be opening and closing? If you don't close() a connection then yes I believe it will remain open, otherwise, why have the close() function?
My habit is to open connection, do sql lookups, close connection.

As Lenny says

If you supply an sql::connection, that connection is used directly and is neither opened nor closed by sql_lookup(). This allows you to open a connection externally and reuse it across sql_lookup() calls.

[pcaspa]

Re: Method to collect session variables

Hi,

I was supplying a connection string for each SQL_Lookup so I assume it would open and close each time. As the file grew that became silly so I changed it as above. Yes if you used an SQL::Connection for SQL_Lookup then that would probably be fine, not that I have tried that.

I'm still learning

Cheers

[Peter.Greulich]

Re: Method to collect session variables

Garry

If you pass in an open connection pointer as Lenny says, I understand it does stay open. Funny thing is, I have never been able to get that method to work for me. Which is why I have always explicitly opened the connection in the lookup as in this method:

Dim args as SQL::Arguments


conn = "::Name::System"
table = "Defaults"
result = "DefValue"
filter = "DefId = " + vDefaultID


GetValue= sql_lookup(conn,table,filter,result,args)

[DaveF]

Re: Method to collect session variables

I just tried it with a pointer to an open connection object and it left the connection open as expected.

dim cn as sql::Connection
dim result as l
dim value as c 
result = cn.Open("::Name::My Database")

value = sql_lookup(cn, "Users", "UserId = 'Test'", "UserId")
cn.Close()

However, if you pass a connection string, I would expect sql_lookup to open a second connection to the database and then close it:

dim cn as sql::Connection
dim result as l
dim value as c 
result = cn.Open("::Name::My Database")

value = sql_lookup("::Name::My Database", "Users", "UserId = 'Test'", "UserId")
cn.Close()