Help with Concatenation - How To Store, Link, Edit, and Display Images and OLE Objects in Microsoft Access Databases


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Help with Concatenation

Darren McMartin

2 years ago

The code from the video is:
S = ImagesFolder
S = S & EmployeePicture

Being a Math teacher, I'm a little confused with the above code. I know it works.

The second line says S = itself plus employeepicture. Looking at it mathematically, which is probably wrong, it is like saying 5 = 5 + 1.

I can understand if the above code was written as:
F = ImagesFolder
S = F & EmployeePicture

I'm just interested why the code above works.

	Richard Rost @Reply 2 years ago
It's concatenation not math. It's adding strings together. Your example of: `5 = 5 + 1` is using basic arithmetic, and is incorrect. Instead let's use algebra as an example: `X = 1 X = X + 4` And now of course your answer would be five. It's the same thing with strings: `N = "Rick" N = N & " Rost"` And now of course the string would be equal to "Rick Rost".

	Richard Rost @Reply 2 years ago
Essentially you can keep adding to a string much like you can change the value of a variable with subsequent calls.

Kevin Yip @Reply

2 years ago

S is a variable, meaning its value can be changed, unlike a constant like 5. The equal sign "=" is an operator symbol here, not an equation indicator. The "operation" here is assigning a value. S=S & A means S is being assigned the value of S & A. 5 = 5 is a mathematically correct equation, but it is syntactically incorrect in coding, because you can't assign any value to a constant, even the same value as itself.

	Darren McMartin OP @Reply 2 years ago
Thanks Richard and Kevin. When I used to write computer code, decades ago, I remember using count = count + 1 in a loop.

	Richard Rost @Reply 2 years ago
That's actually one of the things I like better about a language like C. The symbol to set a value equal to something is different from the symbol to check for equivalences. X = 5 Would set X to a value of 5, but X == 5 Tests to see if X is equal to 5.

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