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Access Data Types Copyright © 2006 Patrick McDermott College of Alameda

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Presentation on theme: "Access Data Types Copyright © 2006 Patrick McDermott College of Alameda"— Presentation transcript:

1 Access Data Types Copyright © 2006 Patrick McDermott College of Alameda pmcdermott@peralta.edu

2 It’s Only Words Most business applications have more text than numbers Text –Up to 255 “alphanumeric”: letters, numbers, spaces and punctuation –“Special Characters”: not letter or number –!@#$%^&*()-=+><|\][{};:’” Memo [up to ~65,000] –Use for sentences and paragraphs: Notes, Comments

3 Numbers Long Integer: Whole Number –Counting Number Plus or Minus 2,147,483,647 (~2 billion) –Too many bils in Bill’s fortune Double-Precision Floating-Point –Range: Big enough 10 308 You can enumerate all the atoms in the Universe. –Precision: at least 15 decimal digits Just enough for $Trillion to the cent. –But NOT enough for a 16-digit Credit Card Number $1,234,567,890,123.45 Decimal ± $792,281,625,142,643,375,935,439,503.35 ± 79,228,162,514,264,337,593,543,950,335

4 Number versus Character Sort As numbers, one & two & three are binary 1 and 10 and 11. As text, 1 & 2 & 3 are ASCII characters 49 & 50 & 51. Numbers sort by value. Text sorts character by character. You can be richer than Bill Gates! As text, $9 is greater than $80,000,000,000! So, just keep $9, and sort net worth as text!

5 Yes/No Logical: true or false. –Checkbox –“Yes” or “No” –“On” or “Off” –We might not have beauty, but we do have truth. –Actually 0 and -1 a.k.a. “Boolean”, switch, flag

6 Attachments Like an Email Attachment Just about Anything Can attach Several files

7 Currency $9,999.99 Varies by country For U.S., U.S. Dollar

8 Dates A Lilian Date 1 is January 1, 1900 36,525 is 12/31/1999 40,544 is 1/1/2011 Fractions for Time –.5 is Noon;.25 is 6:00 A. M. Format depends on your Windows Settings –Forget the Y2K stuff already!


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