Concatenating strings

Recommended Posts

Having issues concatenating strings.  

function SQL_ADD_TEST(string SER_NO, string FIRST_HIGH, string FIRST_LOW, string SECOND_HIGH, string SECOND_LOW, string THIRD_HIGH, string THIRD_LOW)
   local dbase = db.Open("Daq351")
   local executeSTR = Format("insert into app01 (serialnumber, firsthigh, firstlow, secondhigh, secondlow, thirdhigh, thirdlow) values ('%s', '%s','%s','%s','%s','%s','%s')",SER_NO, FIRST_HIGH, FIRST_LOW, SECOND_HIGH, SECOND_LOW, THIRD_HIGH, THIRD_LOW)
   local inserts = db.Execute(dbase,executeSTR)
return inserts

when trying to output to console with ? executeSTR, i get NaN.

I've also tried "insert into...." + value1 + ", " + value2 " but get an error saying it expected a number (in general, i can get the actual error again).

if I hard code the sql, this sequence works fine.


thanks in advance, gene

Link to comment
Share on other sites

OK, three problems:

1) "local" is the wrong declaration.  You want "private".  "local" is for class declarations and never used inside a function.
2) while you remembered to declare all your function parameters as strings, you forgot to declare executeSTR as a string.  So you need:

private string executeSTR = format(...)

This is why you get NaN().  DAQFactory is trying to convert your insert string into a number so it can store it in executeSTR.

3) I typically do not recommend constantly opening and closing a database.  Just open it once at startup and leave it open.  Close it only if you lose connectivity (which is rare).

Two notes:

1) db.execute() doesn't return anything so "inserts" will never have anything
2) I typically prefer to build up my SQL strings over several lines, if only to make it clearer.  So:

private string executeSTR = "INSERT INTO app01 (serialnumber, firsthigh, firstlow, secondhigh, secondlow, thirdhigh, thirdlow) values ("
executeSTR += ER_NO 
executeSTR += ",'" + FIRST_HIGH + "'"
executeSTR += ",'" +FIRST_LOW+ "'"
executeSTR += ",'" +SECOND_HIGH+ "'"
executeSTR += ",'" +SECOND_LOW+ "'"
executeSTR += ",'" +THIRD_HIGH+ "'"
executeSTR += ",'" +THIRD_LOW + "'"
executeSTR += ")"


Link to comment
Share on other sites

Just another suggestion: wrap your DB calls in a function.  So, for example at a minimum (each function is a sequence):

function dbOpen(string dbsource)
   global dbase =
function dbExecute(string sql)
   db.execute(dbase, sql)
function dbQueryToClass(string sql)
   private ret = db.queryToClass(dbase,sql)

Then, instead of calling, db.execute() and db.queryToClass(), call the above functions.  I gave the minimum that they'd do, but you can then add error handling and debugging code to the above to further enhance it.  

The best solution however is to create a class:

class CDataBase
   local handle = 0
   function Open(string dbsource)
      handle =

   function Execute(string sql)
      db.execute(handle, sql)

   function QueryToClass(string sql)
      private ret = db.queryToClass(handle,sql)

Then instantiate a single instance in startup:

global dbase = new(CDataBase)

and call into it like this:"mydatasource")


dbase.Execute("INSERT INTO mytable (field1) values (3.423)")

Again, this allows you to eventually add features (like error handling and debugging code) as needed and encapsulates it into a single object.


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.