Data Capture Forms What are they?

Example 1

Example 2

Example 3

So what is a Data Capture Form? What are the main features of a Data Capture Form? Can you remember from the last 3 examples? Title Instructions to user (to fill in & return details) Boxes to fill in Starred sections that must be filled in Combo boxes (for on line forms with drop down boxes)

So why use a Data Capture Form? Why can’t people just hand over their details on lined paper? How does a DCF help to reduce errors when creating a database?

The Folkestone Academy Student Database The school holds a lot of data about you on a student database. What fields of data does the school have about you? Under the Data Protection Act you have a right to check your details once a year, hence the data forms that are sent out in the 1 st term. This form is ‘out of date’ for modern lives… Re-design an on-line parent/student application form to join the school…. Add , mobile phone and other relevant details Consider the data type to be entered… Alphabetic, Memo, Numeric, Alpha-numeric Date, Object (picture)

Checking for errors… There are TWO main ways in which you can check a database for errors…. V a l i d a t i o n Verification

Where you Look for errors on screen or on printed work! Either you can do it or pass it over to someone else! Proof read! Verification is also where you are asked to enter details TWICE into a computer…e.g. passwords or your address on the Internet!

Verification Computer says no….

Validation This is where the SOFTWARE checks for errors as you type in data into the database. Validation doesn’t guarantee accuracy only reasonable answers are given… E.g. a % mark is between 0 and 100, validation cannot tell whether a test result should be 9.9% or 99%?

Types of Validation checks…. Range Check Sets an upper and lower boundary for the data. Data must lie between these two values Type Check Checks that the data is the correct type e.g. numeric, date, Boolean, currency Presence Check Also called existence checks or required fields. The computer will insist that a value is entered for that field. Length Check A single character has a length of 1. The system may be set to limit the number of characters that can be entered into any field. E.g. a postcode with a space takes a maximum of 8 characters. Picture Check Also known as a Format Check. Some data entries may be a combination of numbers and letters and may have a correct order e.g. postcode CV54 2RT. The first two entries are letters, the next three are numbers and the final two are letters so the check would be: LLNNNLL Check Digit A check digit is calculated using a set of numbers and then added to the end of them. This digit is then used to check that the full code has not been corrupted in any way when it is transmitted or input. Check digits are commonly found in ISBN numbers and on barcodes. Don’t panic By the end of this coursework you will be very familiar with these types of validation checks!

Range check Range checks make sure that numerical data falls between pre-determined limits (i.e. within a certain range of numbers). For example, that the age of a pensioner who is a member of a pension scheme and who is 81 is not entered as 18. This is done by setting a bottom limit on the age range. Range checks are not infallible. In the example of the pension scheme data, if the age of the pensioner had been 96 and it had been entered as 69, the mistake would not have been detected by a range check.

Type check type checks make sure that the correct type of character has been entered e.g. that a number has not been entered where a letter should have been or that a letter have not been entered where a number should have been. E.g to reject hell0…. 1o1 Both misuse zero and o’s!

Presence check Presence checks ensure that data that must be entered is entered. For example, the pension scheme would need a pensioner’s National Insurance number. If that was not entered the presence check would detect this and notify whoever was entering the data.

Length Checks Certain types of data are always the same length. For example, a National Insurance number will have 2 letters, followed by 6 numbers, followed by 1 letter (e.g. YY232425A). A length check will identify any NI numbers that have more or fewer characters.

Check Digit When large numbers are entered into a data system there is always a chance of error. To help to overcome this problem an additional number is often added to the end of the original number. This number is a check digit, and is calculated from the other numbers in the original number.

Check Digit Check digits are often found on barcodes. When the barcode is scanned, the computer automatically removes the end number and uses the rest of the numbers to calculate what the check digit should be. If the result is the same, then the number has been entered correctly.

Check Digit The first number (4) is the check digit. Starting from the left, the next number (7) is multiplied by 11, the second (8) by 10, and so on. Check digit There are 11 digits

Check Digit The total is then found: 7 x x x x x x x x x x x 1 = is then divided by 11 (there are 11 numbers). 315 ÷ 11 = 28 with a remainder of 7.

Check Digit The remainder is then deducted from 11 and the result should equal the check digit (11 – 7 = 4). As the check digit is 4, the barcode has been entered correctly. Check digit

Common types of error are Transcription errors – these usually occur when people entering data misread what they are entering (e.g. mistaking 5 for S or O for 0). Transposition errors – these occur when people entering data get characters out of order or back to front (e.g. 619 instead of 916 or ‘form’ instead of ‘from’).

Go to your worksheet…. FieldExampleRange CheckType CheckPresence CheckLength CheckPicture CheckCheck Digit TitleMr, Mrs, Miss SurnameJones, Bloggs PostcodeCV54 9TE Telephone Number Date of Birth12/09/86 ISBN Number GenderMale, Female Price£19.99 Student Number1435

The answers… FieldExampleRange Check Type CheckPresence CheckLength CheckPicture CheckCheck Digit TitleMr, Mrs, Miss Yes SurnameJones, Bloggs Yes PostcodeCV54 9TE Yes Telephone Number Yes Date of Birth12/09/86 Yes ISBN Number Yes GenderMale, Female Yes Price£19.99 Yes Student Number1435 Yes