Databases Learning Outcomes LO 1 Apply validation to

Databases

Learning Outcomes LO 1 Apply validation to database fields. LO 2 Define verification. LO 3 Research possible ways to enter data by machine

Starter Task 1: Why do we do validation checks? Task 2: You have a customer orders database, think of at least 5 fields that this database would have and what the validation check for each field would be and why.

Quick Recap Validation checks Check Digit the last one or two digits in a code are used to check the other digits are correct Format check The data may have to conform to a particular pattern Length Check The data must be in certain limits Lookup Check Some fields may be looked up to see if they are from an allowed range. Presence Check Makes sure the important information has been included Range Check A number must fall within certain limits Type Check The data type may be restricted

Verification Validation cannot make sure data that you enter is correct, it can only check that it is sensible, reasonable and allowable. Methods: v. Checking data onscreen in comparison to the original documents. v. Entering v. Printing the data twice. out a copy of the data and comparing it to the original paper document.

Its quicker to enter data by machine, there are numerous ways data can be automated. � Barcodes � Magnetic Strips � OCR (optical character recognition) � OMR (optical mark recognition) � RFID (radio frequency identification) � Smart Cards

Hierarchical databases A hierarchical model is sometimes useful when making an inventory. Some parts of stick items may always belong to others. Most data handling situations are not like this and the majority use the relational model.

Plenary 1) 2) 3) 4) What is the difference between verification and Validation, give examples? Name 3 data entry procedures and describe them. What is a flat file database? What is a hierarchical database