Unit 18- D1

Common Errors

Accidental Deletion of Fields

Often, when using a database, it’s only all too easy to accidentally delete data. The most obvious way to avoid this would be to make certain that there are back-ups of the data, so not matter what, you won’t lose it completely. However, it’s still very annoying when information is deleted and it takes both time and effort to re-type or reload the data. To prevent any deletion whatsoever, the best thing to do would be to set or customize the database (ROM) so only the designer can manipulate it, therefore anyone using the database will only be able to view it and run no risk of the common error.  

Incorrect Data Types

This issue occurs when an unmatched data type is used. For example, if a database is used to keep record of the number of stock a business has, it will go wrong if instead of inserting a numerical value (the data type) the clerk inputs a text value, like ‘ten’ instead of ‘10.’

To avoid this, the database can be programed to inform the user with use of an ‘error code’ message, like the irritating red asterisks on online e-mail forms where you’ve used the wrong characters for a password or something of the sort.

An additional help would be options like a drop down menu, this would minimize the issue of incorrect data.

Renaming Incorrectly

Re-naming something or someone incorrectly on a database can be a huge mistake, especially in the case of a bank as big as Barclay’s. This is more than often human error, of a crackly phone so the information is misheard. Unfortunately, unless the glitch is spotted it won’t mend by itself, so the clearest way to avoid this sort of problem would be to double check the information someone is giving you. This is why people who work in administration often ‘parrot’ your information back to you, your name and how it’s spelt and so on.     

Validation

Validation in computers is similar to when real people verify and it’s the process of ‘checking’ the data. When a user inputs information into a database, it’s more than often that he or she will type in something that doesn’t quite make sense of match (human error). It would therefore be the job of the computer to ‘validate’ the information and make sure that it’s correct. After that, it’s the persons turn to verify that data, so it’s almost like a two way system.

For example, social networks like Facebook hone ‘limits checks’ which wards off possible users if they are under the age of 18. Likewise, the database developer would put a restriction on number value insertions, to reduce the risk of over paying for an item.  

Null Values

A null value basically equals ‘nothing there’ and is a blank space in a data sheet.  This is a problem as the database will then not be able to function properly as it doesn’t understand the commands. A condition will often have the ‘true’ ‘false’ or ‘null’ option, if the database hasn’t been set to understand the option of a null value’ it won’t work, like registering for ‘Hotmail’ and missing out some of the information it needs on the form sheet. It stops the potential user from carrying on.