Drew Wutka
DWUTKA at Marlow.com
Mon Feb 19 11:08:10 CST 2007
Yes, I'm listening...been sick since last Wednesday...just coughed and sneezed in envelope for ya, what's your mailing address? <grin> All this binding early/late of Excel, haven't ya all figured out how to use ADO to modify excel files? Admittedly, it doesn't do formatting, but for data transfers it rocks! Drew -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of JWColby Sent: Friday, February 16, 2007 9:39 AM To: 'Access Developers discussion and problem solving' Subject: Re: [AccessD] Missing references It is quantifiable. I have a class for timing things and you can do late binding vs. early binding in a loop a million times to measure the effects of each. Essentially binding requires the compiler to look up the object in an object table to obtain the pointer to the object as well as the parameters, their types, the return type if any etc. Early binding does that at compile time, once. Late binding does the exact same thing at run time, every time the object is resolved. The question is, how often is it done? For example, if you have a global reference to a word object, at runtime the object has to be resolved, but since it is a global variable, it is only resolved once, and so the hit is a once-off affair. Now take the example of a reference to a word object in the header of a class module. Now this has to be done once, every time the class loads, for each instance of the class loading. Now take the example of a reference to a cell in a spreadsheet dimensioned in a method of a class. The object has to be resolved every time the function is called. That may be once, or it may be hundreds or thousands of times. Notice that in ALL cases, the object is resolved ONCE for each dimension statement. The difference between these three examples is the LOCATION of the dimension statement. It is actually possible in VBA to dimension an object down in code, so you could literally dimension an object inside of a loop. Generally speaking that would be a disaster using late binding. Actually dimensioning a variable of any kind down in the middle of code is considered bad practice anyway. DREW are you listening? Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. Bad Practice. <HUGE grin> John W. Colby Colby Consulting www.ColbyConsulting.com -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of artful at rogers.com Sent: Friday, February 16, 2007 10:21 AM To: Access Developers discussion and problem solving Subject: Re: [AccessD] Missing references Is this verifiable, Jim? I haven't ever used late-binding, which I admit has caused various installation issues, but I am curious. Is this a thumbnail calculation or can you supply concrete arithmetical evidence? A. ----- Original Message ---- From: Jim Dettman <jimdettman at verizon.net> To: Access Developers discussion and problem solving <accessd at databaseadvisors.com> Sent: Friday, February 16, 2007 9:49:44 AM Subject: Re: [AccessD] Missing references Bryan, One thing you didn't mention is the performance hit; late binding costs you 10-15% for every operation perform. Jim. -- AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com -- AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com