Databases

Learning Outcomes LO1 Apply validation to database fields. LO2 Define verification. LO3 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. If data is entered incorrectly then integrity is lost. Validation checks are therefore carried out to check the data entered into the system is reasonable for the field.

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 Check Digit- bar code readers in supermarkets use check digits Format Check- national, insurance number, car registration Length Check- telephone number Lookup Check- Postcodes can be looked up to see if they exist Presence- application for a bank account must have a surname Range- concert may be allowed 4 tickets Type- persons name restricted so that no numbers are accepted

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

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 Task pupils to write what each is after explanation along with examples! INTERNET RESEARCH TASK Barcode: Scanning the data replaces typing. You can then edit the scanned data, accept it by hitting the enter key, or whatever else you deem appropriate. This is the classic case of keyless data entry. Magnetic strips: are built into many plastic cards such as debit or credit cards and personal identity cards. The magnetic strip on the back of the card can hold the personal details of the card owner and, with the necessary PIN, will allow access to secure information, eg bank account details. Data stored on the strip is scanned and input into a computer system by a magnetic stripe reader. OCR: It is a technology that recognises and captures alphanumeric characters on a computer at high speed. It reduces the data entry time and increases its accuracy when compared to the use of manual data entry operators. EXAMPLE office of national statistics may use OCR to scan questionnaires and then store the data. OMR: recognises marks on paper for instance when you do multiple choice tests the computer marks them. RFID: There are a lot of interesting ways to use RFID products in the medical field. However now that the tags, themselves, can be made small; pharmaceuticals, lab samples, wristbands and other medical equipment can be tracked and traced, and data entry can be automated. Thus, RFID products in the medical field are aiding in the elimination of medical mistakes. A smart card: typically a type of chip card, is a plastic card that contains an embedded computer chip–either a memory or microprocessor type–that stores and transacts data.

Hierarchical databases A hierarchical model is sometimes useful when making an inventory. Some parts of stick items may always belong to others. Looked at flatfile database and how to validation and verification of data works in a database. Now look at two other data models Hierarchical and then relational next week. Most data handling situations are not like this and the majority use the relational model.

Plenary 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